By Jim Liddil
For me, the purpose of this article is to organize and present some of the various information and scientific research on how lambic is made in Belgium, and how you can make beer in the style of lambic at home. The information I will present in this article is a condensation of material from various sources. These include research papers and dissertations from Belgium, articles written by various other authors, “Lambic” by Guinard, personal accounts from people who have been to lambic breweries, postings from the internet Lambic Digest and my own personal experiences. I hope to provide accurate information that will aid you in your attempts to make lambic-style beer.
First off, I will do my best to refrain from using the word lambic to describe any beer made outside Belgium. Lambic is only made in a small area outside Brussels, even though one American craft brewer might have you thinking otherwise. In my discussion of making similar beer by the homebrewer I prefer to use the term lambic-style. On the internet lambic Digest one sees the term plambic being used, which is short for pseudo-lambic. Again with the point being that real, true lambic is only made in Belgium and nowhere else. If you find this view extreme I hope that reading this article and some of the other writings cited here will help change your mind.
I will not delve deeply into the history of lambic here as it has been covered adequately elsewhere (1,2,3). Suffice it to say that lambic is probably one of the oldest styles of beer still made today. The problem now is that lambic brewing is in danger of ceasing to exist. This is due to the changing European economic market, changes in consumer preferences, and the artisanal nature of lambic brewing. It will be a sad day when beers like Cantillon are no longer available.
I live for lambic some would say. In preparing this article I seemed to spend all my spare time reading and re-reading and taking notes from the various technical publications, articles and books I have on the subject of lambic. Being a scientist in real life I have tried to do a complete analysis of all aspects of the process of lambic production. From wort production to fermentation to blending and bottling. My goal has been to try to decipher the lambic brewing process and what aspects may or may not be important to the homebrewer trying to make a similar style beer.
Lambic is made by what many consider an anachronistic process. The grist is made up of 30-40% raw unmalted wheat with the remainder being malted barley. The mashing process is carried out using a technique called turbid mashing. Unlike decoction mashing the liquid portion of the mash is removed and boiled, leading to poor conversion and large amounts of unconverted starch ending up in the finished wort. Whereas most brewers want the freshest hops, lambic brewers use hops that have been stored in the open for 2-3 years. The wort itself is not inoculated with a pure strain of yeast. Instead the brewer allows the wort to cool overnight in open cool ships. This way any microorganism in the brewery can get into the wort and grow. These organisms include various bacteria and wild yeast. And finally, the beer is fermented not in stainless steel but in oak casks for upwards of 3 or more years before bottling. So as you can see lambic is not your ordinary beer.
These are the essential defining characteristics of real lambic. Again, as homebrewers we do not have to follow tradition to the letter. We do not live in Belgium and most of us have not been making beer by this method for hundreds of years. But also remember that these points only define lambic in the broadest sense. They do not provide insight into the nuances involved in obtaining a product of the character and flavor profile of a Cantillon Rose de Gambrinus or a Boon vintage dated Mariage Parfait.
I have always felt this quotation by Michael Jackson really describes how I feel about lambic beer. “The lambic family are not everybody’s glass of beer, but no one with a keen interest in alcoholic drink would find them anything less than fascinating. In their “wildness” and unpredictability, these are exciting brews. At their best, they are the meeting point between beer and wine. At their worst, they offer a taste of history.”(2)
Quite often people are quite shocked by the extreme flavor profile of lambic or my attempts at recreating the style. Too often people immediately dismiss the beer as undrinkable and infected without really “tasting” the beer. Of course this reaction is not unlike the that of a hard-core Budweiser drinker tasting a beer like Chimay for the first time.
Making a lambic-style beer at home can be as simple as boiling up some extract with hops and adding a few yeast and bacteria cultures. Or one can go to extremes using traditional turbid mashing schedules, spontaneous fermentation and aging in oak casks. As a homebrewer you have many choices available. But based on my experience do not expect to have a product of similar character to any of the real lambics in a few weeks or even months. It will take years!
Using the various resources at my disposal I have a very
general idea how lambic is made in Belgium. Remember
lambic making is an artisanal craft and the brewers are
somewhat secretive about giving exact details of how they do
things. Most Belgian brewers seem to be willing to “make
up” an answer rather than give none at all. And because it
is a craft, there is a great deal of experiential knowledge
involved which one can not learn by simply following a
recipe. So remember this information is only very general
and should not be taken as the gospel truth.
Making lambic-style ale requires a great deal of patience.
Most homebrewers who want to make such a beer think that
because they can make a regular ale in a few weeks that
they should also be able to make a lambic like beer in the
same period of time or maybe a little longer. Many brewers
expect that within a few months they will have a product
that is ready to bottle and that after that it will be ready
to drink in another few weeks. I have seen this view
expressed on the internet and also in the recipes I have
seen from the AHA National Homebrew Competition.
Unfortunately the recipe section of “Lambic” (2) does
little to dispel this belief. Real lambic is not made in a
few weeks or months. It takes years for it to become the
complex product you find in the bottle. There is no magic
formula for “instant” lambic-style ale. The microorganisms
used in the fermentation grow very slowly and are equally
slow at producing the flavor profile that gives a product
that has depth of character.
Do not think that a few months is enough time to make such a beer. I feel you need to wait at least a year before you even consider bottling the beer or adding fruit to it. If you are not prepared to wait this long then I suggest you do not try in the first place. This may seem like an extreme view, and it is, but lambic-style beer making is not something I take lightly. You must be prepared to fail even after investing a great deal of time and effort in the production of such a beer. Don’t “imagine” the beer developing a pellicle, ropiness or Brettanomyces character. Either it will or it will not. There is very little you can really do to change what ultimately happens in the fermentation vessel.
You can use traditional mashing techniques, use all the right ingredients and add all kinds of wild yeast and bacteria, ferment in a cask for years and still end up with a totally disappointing product. Do not say you were not warned. Your beer may end up so acidic you will want to use it for cleaning calcium deposits off of your brew kettle or it may be so mild that it barely passes as infected beer. And even after bottling, the beer can undergo large changes in flavor. So be prepared for a large amount of uncertainty all along the way.
Give up any notion that you are going to make a product like Boon or Cantillon even with a great deal of experience. You cannot buy a kit or follow some recipe in a homebrew shop catalog and end up with a well balanced, complex product. Your beer is not going to develop Brettanomyces character, nor will it develop the proper acidity in a few weeks. It will not develop a melange of flavor after two weeks in the bottle. Am I making myself clear? The path to the Holy Grail may take a lifetime. Now having said all this I still feel that with a bit of effort and patience anyone can produce a reasonable lambic-style ale in the home setting.
Having spoken to Dr. Guinard I realize the he felt the recipe section could not possibly do justice to this style of beer. Also he was working within the constraints of what was considered practical for the average homebrewer. I think most brewers who have tried to make pure culture lambic-style beer will agree that the times he suggests for fermentation and bottle conditioning are far too short to achieve a product with a character truly similar to the real thing. He suggests that a few weeks of fermentation and a few weeks of bottle conditioning are all that is required to achieve a beer with lambic-like flavor. As stated, myself and others would largely disagree with this assertion. At the same time I think he and Brewers Publications realized that few homebrewers would even think about buying a book that had recipes that suggested the beer be allowed to ferment for a year or two and then undergo bottle conditioning for another year or more.
But of course those of us who have pursued this type of brewing have found this book to be an invaluable resource and an excellent stepping stone. Using it as a guide we have been able to locate other sources of information and do testing on our own. We have found that the traditional fermentation and aging process is indeed necessary to achieve a truly characterful beer. We have learned an appreciation for the craft of lambic brewing and the fact that it is a dying art. I highly recommend “Lambic” (2) to anyone considering making pure culture lambic-style beer. Just keep in mind that you are better off getting the beer started and then forgetting about it for a year or two. Great beer is not something that can be rushed.
These days more and more homebrew shops are supplying flaked or rolled wheat. These forms of wheat can also quite often be found at a natural foods or cooperative market. These types of stores also usually carry raw wheat of either the hard or soft varieties.
If one chooses to use raw wheat there are a couple of different mashing techniques one can choose to follow. The easiest method is to pregelatinize the wheat as described by Guinard (2). After this is done the whole mash is combined and either a single step or multiple step mash followed. Alternatively the wheat can be combined with the malt directly and then mashed using a single or multiple step mashing procedure. The final and most time consuming procedure involves what is called the turbid mash method. In this method the crushed raw wheat and malt are combined and a portion of the liquid is removed and boiled to raise the temperature of the mash to each mash temperature point. In the mashing section various schedules will be described in more detail.
(set up a table format for mash schedules)
A word about crushing raw wheat is in order. Because it has not been malted and kilned it is not friable. Raw wheat has a tendency to be squished rather than crushed. This makes it hard to mill even with a roller mill. Running the wheat through a roller mill multiple times will help reduce it to fairly small particles. If you have a Corona-type mill this is one place where it may have an advantage over one of the various roller-type mills available. Wheat has no husk so grinding it up to a fine powder is not a problem.
A final note concerns the use of wheat flour. A few individuals have reported replacing the wheat fraction of the grist with whole wheat flour. They reported no problems with a stuck mash or slow run off. Of course as they say, your mileage may vary. Whether or not this will work for you will depend on your mashing and lautering setup as well as your level of experience. If you are feeling adventurous give it a try.
The simplest approach to making lambic-style ale is to use extract, either dry or liquid. Since you want and need extra amino acids and dextrins in the wort to support the long fermentation you should consider using an extract meant for making wheat beer. These are typically made from 60-70% malted wheat and are readily available in liquid and dried form. You can also blend the wheat extract with malted barley extract to achieve a 30-40% wheat content. You might also consider buying some 100% wheat extract and blending it with malt extract at the more traditional 30-40% range. The 1994 AHA Homebrewer of the Year brewed his lambic-style beer using the wheat based extract produced by Briess. So do not despair thinking that you can only make lambic-style beers if you are an all grain based brewer. You should get the freshest extract possible and carry out the boil for a full hour to maximize the extraction of the hop antiseptic compounds and to precipitate the excess proteins in the extract. The main problems with extracts as a whole are that they generally produce beers darker than equivalent all grain beers and the extracts themselves may be somewhat nutrient deficient (5,6).
If you are an all grain brewer you have a number of options available. You can choose to use malted, flaked or raw wheat in your mash as well as performing various mash routines. Probably the simplest mash consists of 30-40% malted wheat with the remainder being made up of 2 row pils or lager malt. This can then be mashed using a single step infusion mash in the 150-155 F (65-68 C) range. This will produce a reasonable dextrinous wort that is also very light in color. Or you could also modify the mash schedule using a step mash or decoction mash of the type outlined by Warner(7). Such a mash technique helps break down the excess wheat proteins and provides the extra amino acids needed by the various yeast and bacteria. One problem, though, with an intensive mash schedule is that it can lead to too much break down of the dextrins in the grist and thus too little carry over into the wort.
The more traditional lambic mash uses unmalted wheat, and as with malted wheat you have a number of options available depending on how traditional you want to be. If you are concerned about having to take time to gelatinize the wheat or do not want to deal with raw, ungelatinized wheat directly in the mash, then you can choose to use flaked wheat. Flaked wheat, also sometimes called rolled wheat, has already been gelatinized for you. All you have to do is add it to the grist and carry out whatever mash schedule you feel is appropriate. Generally flaked wheat can be found at homebrew shops or at your local natural foods' market or co-op.
Raw wheat, in the most traditional method it is not pre-gelatinized before being added to the mash. Because of this, a very time consuming form of mashing is carried out and will be discussed in more detail later. The easier route is to grind the raw wheat and then gelatinize it before adding it to the mash. This is accomplished by adding water to the wheat at the rate of 1.5-2 quarts per lb. along with 10% of the malted barley. The mixture is heated to the 150 F (65 C) range and allowed to stand for 15-30 minutes. This allows the enzymes in the malt to act on the wheat starch and aid in their hydration. After the temperature rest the whole mixture is heated to boiling with constant stirring. Feel free to add water as the mixture begins to thicken. Be sure not to heat it too fast or stop stirring, otherwise you will have a big gummy burnt mess. After it has boiled for 15 minutes you can then add it to the main mash and continue with the mashing schedule. Add the boiled wheat to the main mash slowly with stirring so as not to raise the temperature of the mash too quickly or unevenly. When using this method the author prefers to have the mash at 100 F (37 C) and then add the boiled wheat, slowly. The temperature will settle in the 120-130 F (49-54 C) range depending on the volume. Then begin to heat the entire mash slowly to the various step temperatures. A fast method involves resting at 130 F (54 C) or so for 15 minutes then raising the temperature to 145 F (63 C) and holding for 15 minutes and then raising to 152 F (67 C) and holding for another 30 minutes, followed by mash out and sparging.
The most time consuming and labor intensive method of mashing involves what is called turbid mashing. This type of mashing involves removing the liquid portion of the mash, boiling it and then reintroducing it to the whole mash. This is somewhat like the reverse of decoction mashing in which the grain portion is removed and boiled. A good explanation of this whole mashing process has been provided by Guinard,(2) with further details provided Lodahl (3). Keep in mind that lambic brewers all have their own individual methods of turbid mashing and some do not use turbid mashing at all.
The goal of the turbid mashing procedure is to break down the larger proteins of the raw wheat and malt into free amino acids and produce a wort high in dextrins and starches. A traditional turbid mash is carried out by mashing in and then removing the liquid portion and boiling it and at the same time adding boiling water back to the mash to raise the temperature. This procedure of removing the turbid liquid, boiling it and adding boiling water to the mash is carried out a number of times until the mash reaches a temperature at which the addition of the boiled turbid runnings raises it to saccharification temperature. After a 2 hour saccharification the wort is run off and the grains sparged with close to boiling water. Again this whole procedure helps break down the ungelatinized raw wheat giving one a wort high in amino acids, dextrins and starches. The whole process is followed by a 4 to 5 hour boil to reduce the large volume of liquid and precipitate the excess proteins and burst any starch granules.
A simplified turbid mashing method was proposed by Frank Boon (8). He suggested mashing in at around 86 F (30 C) using as little as 0.5 quart of water per pound of grist. The mash should then be stirred and the milky wort should be run off and boiled for a few minutes. In the mean time fresh water should be added to the grist and a step mash performed of your choosing. After reaching the 140 F (60 C) range the boiled milky wort is added back to the mash to raise the temperature to the saccharification range. Then the mash should be allowed to rest and undergo saccharification. After this the wort should be run off and the grain sparged. This produces a large volume of liquid and is one of the reasons for the suggested 5 hour boil.
The sparging of a lambic mash is typically carried out with water that is hotter than 165 F (74 C) usually closer to 190 F (88 C). This aids in extracting dextrins and unconverted starches from the mash. This procedure also extracts tannins from the malt as well, but these are precipitated out or broken down over the long fermentation cycle and do not contribute to astringency in any large part. The use of hotter than normal sparge water is particularly important if one follows a true turbid mash type schedule due to the poor conversion. In normal beer production one does not want all of these various components extracted into the wort but in lambic brewing they are needed to support the long fermentation process and will ultimately be utilized by the yeast and bacteria. Without these usually undesirable products the lambic organisms may not thrive and produce a beer with the right flavor characteristics.
Whether or not a turbid mash is required to achieve optimal flavor in a lambic is a matter of debate. There are some lambic brewers who do not use this method. But two of the more traditional brewers, Boon and Cantillon do use it.
Be aware that you will probably not get complete starch
conversion in a mash with raw wheat regardless of how
rigorous a mash schedule you use. But this is not a
problem since you want a certain amount of unconverted
starch to carry over into the wort to provide a substrate
for the microorganisms to feed upon late in the
fermentation and maturation.
Turbid Mashing for the Homebrewer
The following is a conversion of the Cantillon turbid mash
schedule to homebrew scale.(3) Based on the information
presented in the article from Brewing Techniques, the
Cantillon Brewery gets approximately 33-34 pts/lb/gallon.
The grist is composed of 34% Raw Wheat and 66% Malted Barley. A number of assumptions have been made in scaling down this mash schedule. It is assumed the we want to end up with a wort with an original gravity of approximately 1.048. It was also assumed that a yield of 30 points/pound/gallon would be obtainable using this method. As will be seen this assumption was not valid for this mash schedule carried out using the equipment and methods described. Your own individual results may vary.
The recipe was designed to provide 5 gallons of wort with an original gravity of 1.048. If we assume that we can get 30 points/pound/gallon then we need a total of 240 points.
We will assume one pound of grain yields 30 points. We want a 1.048 OG wort of 5 gallons. This is 48 points X 5 gallons = 240 points total. 240 points/30 points/lbs of grain = 8 lbs of grain.
For 5 gallons you will need 240 pts total. 240 pts/30 pts/lb/gallon = 8 lbs of grain Based on this calculation we will need 8 lbs. of grain. For a further explanation of mash calculations see reference (9).
The grist is 66% malt and 34% raw wheat. The barley malt fraction is 66% of 8 lbs which is 8 lbs X 66% = 5.3 lbs malt. 8 lbs total minus 5.3 lbs of barley malt equals 2.7 lbs of raw wheat.
The Cantillon schedule calls for mashing in 1300 kg grain/850L water (2860 lbs/900 qt) = 3.2 lbs/qt or 0.3 quarts of water/pound. We have 8 lbs of grain X 0.3 quarts = 2.4 quarts of water. In all of the following steps the temperature and water additions were taken directly from the Cantillon schedule as published and scaled accordingly.
1.) In kettle #1 add water at 144 F(62 C) to the crushed grain to achieve a temperature of 113 F (45 C) (about 2.4 quarts of water). Mix grain and water thoroughly and allow to rest at 113 F for 10 minutes. This amount of water is enough to just wet all the grain and flour. The mash needs to be stirred very well to make sure all the grain is wetted and no clumps of flour are present. Total time for this step is about 20 minutes, with the temperature rest included.
2.) Next, add enough boiling water (212 F)(100 C) to the mash to bring the temperature to 136 F (58 C). Do this over the course of 5 minutes making sure to mix thoroughly. Allow the mash to rest for 5 minutes at this temperature. Remove about a quart of liquid from the mash and add to kettle #2 and heat to 176 F (80 C). It will take about 3.5 quarts of water to raise the temperature to 136 F and you will end up with a very soupy mash with plenty of excess liquid. The liquid taken off should have the appearance of milk. Once heated it will clear up and large particles of hot break will form.
3.) Add more water at 212 F (100 C) to the mash over the course of 10 minutes to bring the temperature to 150 F (65 C), again with constant mixing. It will take about 5 quarts of water to achieve this temperature. Allow the mash to rest for 30 minutes at 150 F (65 C). At this point the mash will be very soupy and the liquid much less milky in appearance.
4.) Next remove 4 quarts of liquid from kettle #1 and add to kettle #2. Continue to heat kettle #2 at 176 F (80 C). The liquid removed from kettle #1 will be very cloudy but not quite as milky as the liquid previously removed.
5.) Add more 212 F (100 C)water to kettle #1 to bring the temperature to 162 F (72 C) and allow to remain at 162 F for 20 minutes. Again it will take about 5 quarts of water to reach the rest temperature. The mash should be very thin and soupy with a great deal of small particulate matter in the liquid portion of the mash.
6.) After the 20 minute rest the liquid in kettle #1 is run off and brought to a boil in a 3rd kettle (#3). Enough of the liquid in kettle #2, at 176 F, is added back to the mash in kettle #1 to bring the mash to a temperature of ~167 F (75 C). The mash is allowed to rest at 167 F for 20 minutes. Any liquid left in kettle #2 can be added to the previously collected run off in kettle #3. It will take most all the liquid in kettle #2 (~1.25 gallons) to raise the temp of the mash to 167 F.
7.) After 20 minutes the wort in kettle #1 is recirculated to clarify it and the sparging with 185 F (85 C) water is begun. Sparge until run off gravity has dropped to less than 1.008 and boil it with the previous run off from kettle #1. Boil the wort, now in kettle #3, until the volume is reduced to ~ 5 gallons.
8.) As the wort begins to boil it is hopped with approximately 4 ounces of aged hops as described in the Hops section. With all the water additions and sparging you will end up with about 9 gallons of wort. Total boiling time to reduce this volume to 5 gallons will depend on what kind of setup you have. At the beginning of the boil the wort will be cloudy and full of large flocculent break material. As the boil proceeds the wort should clarify as the proteins continue to coagulated and the starch is solubilized.
After boiling, the wort can be cooled using your method of choice. This method of mashing does not seem to yield the large amount of break that a typical all malt infusion mash will yield. But as stated earlier your results may vary depending on your equipment and technique.
Using this method yielded a wort with an OG of 1.040. This is ~ 25 pts/lbs/gal. Thus the mash efficiency was not as high as that obtained at Cantillon. The yield could probably be improved by extending the times for the various rest steps. Also it may be a good idea to heat the liquid withdrawn from kettle #1 each time at a very slow rate. To play it safe you may want to start out with a larger grain bill based on the more conservative yield of 25 pts/lb of grain.
The homebrewer has a couple of options with respect to obtaining and using aged hops. The brewer can buy hops and leave them out at room temperature for a year or two to age and lose bitterness. This requires planning and is not convenient for the beginning lambic-style ale brewer. Alternatively you or a friend may have some old hops that you just could not part with but have never used. If these are old enough they may serve the purpose. New hops can be purchased and heated at low temperatures (<200 F) on a cookie sheet for 4-5 hours. This procedure can also be used for any hops you may have around and want to use. Typically you want to heat the hops until all the aroma has been driven off from the hops. Be aware that the smell may not be one that others find pleasant. This author finds that leaving hops in the Arizona summer sun for a week or two seems to do a very good job of aging them. If you have a total aversion to "ruining" perfectly good hops you may be able to find hops at a reduced price at the end of the year from your local homebrew shop or one of the many homebrew mail order supply companies. Many times natural foods or cooperative stores have hops in the herb department. These are usually well aged and devoid of aroma with well oxidized lupulin glands.
Whether you use whole or pellet hops does not seem to matter as long as they are well aged. They can be used both alone and together depending on what you have on hand. Crushing the pellets into powder will help to enhance the oxidation process. As the hops age they take on a very pale green to yellow color and lose all aroma and the lupulin in whole hops turns from yellow to orange-brown. During the aging process the hops go through a stage of smelling rancid and cheesy. This smell is unpleasant so it is best to leave them in a well-ventilated area. You may want to put the hops into a container with a fine mesh cover of some sort. Then every once in a while you can mix the hops to enhance oxidation.
In spontaneously fermented lambic there is a succession of growth of the various organisms as described in Lambic and elsewhere (2, 10, 11, 12, 13). With pure culture lambic one has numerous options regarding when and how to add the various microorganism. These range from simply adding all the cultures right after cooling, to adding each organism separately at various times to mimic the spontaneous fermentation growth cycle.
The whole process is further complicated by the decision of what size inoculum to use. Should one try to duplicate the traditional method where the initial number of cells/ml wort is very small or should one use larger cell numbers to ensure proper growth of these microorganisms? There is not a simple answer to these questions and again many techniques have been and need to be tried.
The Brettanomyces and Pediococcus are slow growing microorganisms requiring special environmental conditions to grow. Even under the best conditions traditional lambic brewers have problems with some cask not fermenting properly because the various organisms fail to thrive or grow too much (14). (See Table "Variability of Fermentation") The same thing can happen to those trying to make lambic-style beers using pure cultures. If the environmental conditions are not correct to start with or change too quickly, one or more of the microorganisms may fail to grow or grow too much and the resulting beer will lack the proper balance of flavors. Of course there are not any definite answers as to how to ensure the balanced growth of all the organisms either.
A number of individuals have tried varying the starter size as well as the addition schedule. Because lambic-style ales take so long to develop the results so far are not conclusive. One thing is known, and that is that you need to have healthy cultures to start with and you need to provide them with the proper environment with all the necessary nutrients for growth. These goals can be achieved by buying fresh cultures and using fresh extracts or all-grain wort.
Temperature control is not as crucial in lambic brewing as with other styles of brewing, but one should still try to avoid extreme temperatures and fluctuations. A temperature that is too high or low may lead to too little or too much growth of one or more of the various microorganisms. In Belgium the temperature of the lambic cask rarely exceeds 77 F (25 C). Those who have been to Belgium have noted that it is generally pretty cool most of the year. It has been noted by one person that even in April the Boon Brewery was cold. At the same time do not get too concerned about the temperature since it may be hard to find an ideal temperature environment for the 1-2 years it will be fermenting. Overall you may be better off having your beer too cold than too warm. It is speculated that cold temperatures will help prevent over acidification of the beer by the yeast and bacteria. At the same time this will allow the other flavor characteristics to develop.
The truly dedicated brewer might consider having a fermentation area with both heating and cooling. Then by checking the weather reports for Brussels, Belgium each day via the internet he could make temperature adjustments and have his beer ferment at close to the same temperature as the real thing.
As a homebrewer you have many options available to you. You can use real whole fruit, fruit juice or fruit extracts or a combination of these. From the information I have gathered it appears that approximately 2 lb. of fruit/gallon of beer is the amount used by a number of the lambic brewers in Belgium. (See Table) You might think any fruit would work, but this does not seem to be the case. You really should use a strong flavored, tart fruit such as sour cherry or raspberry or possibly blackberry. Less intense fruits simply do not have the flavor to stand up to the flavor of lambic- style beer and refermentation. Of course there are exceptions to this general view. As stated before some lambic brewers have gone to using almost any fruit under the sun. They are able to get a highly flavored product through the use of fruit juices and syrups. They also add sugar to the beer, blend it with very young lambic, force carbonate and pasteurize. Of course then they end up with a product which many feel is very far removed from traditional lambic.
In order to emulate what traditional lambic brewers do you should use plenty of real fruit, of the best quality you can find. Again based on the information gathered you will want to let the lambic-style beer stay on the fruit for 3-6 months. The lambic- style ale you use should be at least one year old and should show some potential of being a nice beer without adding fruit. You are not going to make a silk purse out of a sow's ear. You will not magically transform a so-so gueuze-style lambic into a Cantillon Rose de Gambrinus clone simply by adding fruit!
If you are going to add fruit to a beer rack the beer into a larger vessels such as a 8 gallon plastic fermenter. This will allow for the extra volume from the fruit as well as provide head space as fermentation begins again. Let it settle for a few days and then add the fruit. Add the fruit carefully to avoid splashing and excess aeration of the beer that may lead to acetobacter contamination and growth. Alternatively you can rack the beer onto the fruit. You can use fresh, frozen or canned fruit. You may want to crush the fruit prior to addition. You may also want to look into the fruit puree products that are available. Refer to the supplier list (Oregon Fruit Products). If the beer has developed the right mix of Pediococcus and Brettanomyces then the conditions in the beer should prevent growth of any unwelcome microorganisms that may be present on the fruit. If you are going to use fresh fruit make sure it is clean and free of molds and dirt. Whether you crush the fruit or not will probably have little effect as the various microorganisms should be able to break it down after a few months.
After the beer has fermented on the fruit for the required time rack the beer off the sediment into another vessel. Then allow it to settle for a few weeks. Doing this lets any large pieces of material that may have been racked over to settle prior to bottling. When ready to bottle rack the beer yet again and follow the bottling instructions for a standard gueuze style beer.
Brewer Fruit Amount (lb/gal) Boon (8) Kriek 1.67 Framboise 1.67 Mariage Parfait (all) 2.0 Cantillon (15) Kriek 2.0 Lindemans (16) Kriek 1.7 Framboise 3.8 Peche 3.4When making lambic-style beer with fruit, it is difficult to make a product that has good lambic-like qualities along with balanced fruit flavor. As already stated many lambic breweries now add fruit juice and pasteurize their products and this gives them a sweet, fruity product. This is not the kind of balance many of us are trying to achieve. For many of us an ideal product is something like a Hanssens Kriek or a Boon 1986 Mariage Parfait Framboise. These are products with an assertive lambic quality and an excellent fruit flavor, without being toothache sweet.
The question among homebrewers has always been how does one make such a product? Of course you must start with a good base lambic-style beer and use plenty of fruit. But even then many of us have failed at our attempts to reach Nirvana. Opinions vary on how one might achieve a good fruit lambic-style beer. Do not use a beer that is excessively acidic or "hard" as the base. If you need to, blend it with some younger "softer" beer. Fruits like raspberries contribute their own acidity to the beer. Starting with a too acid beer just seems to make matters worse. Ferment the beer with fruit at cool temperatures to slow the growth of microorganisms yet allow the beer to extract the flavors from the fruit. Cool being something in the range of 60 F or less.
Based on some limited experimentation it seems that sweetening a fruit beer that is overly sour helps bring out the fruit. The problem is as long as there are live microorganisms in the beer, they will ferment any sugar you add to the beer either before or at bottling. It has been suggested that one traditional lambic brewer adds unfermentable sugar in the form of saccharin to the beer at bottling so it retains its fruit character without being pasteurized. Saccharin works well when added to lambic in the glass to counter the acidity. If you choose to try saccharin dissolve it in a small amount water and add it to a glass of beer using an eyedropper to see how you like it. Many people find a little saccharin goes a long way. And some find the sweetness from saccharin too "chemical" in nature. So test it before you decide to add it to 5 gallons of precious beer.
Another option is to sterile filter (0.2 micron) the beer prior to the addition of fruit (whole, syrup or extract). Allow the filtered beer to extract the fruit flavor, if using whole fruit, for a few weeks. Fine the beer (if using whole fruit) and then add sugar as needed and keg it and/or counter pressure fill bottles. Using this method you can achieve a product that has a balance of qualities you enjoy. This is a far from traditional method. But after all this is not Belgium and we are homebrewers so we can do whatever we want. Please remember not to call it lambic.
Let's start with the standard food grade high density polyethylene (HDPE) container. These come in a variety of sizes ranging from 5 gallon buckets up to drums of 15 gallons or more. These vessels have the advantage of being inexpensive, light weight and practically unbreakable. Also HDPE is somewhat permeable to oxygen and other gases. This will provide for a slow and continuous gas exchange during the lengthy fermentation and may aid in the growth of the Brettanomyces and subsequent flavor development and maturation. This is purely speculation based on the fact that wood is also gas permeable and is the traditional material used for lambic fermentation.
A possible disadvantage of HDPE is that it is a plastic and being such is relatively soft and the surface can become scratched. The scratches in the surface may then harbor the wild yeast and bacteria from the fermentation process. Some people feel that a plastic vessel once scratched can never be adequately cleaned and sanitized. This theory has never been proven but is considered part of homebrewing folklore. Thus once a plastic vessel is used for making lambic-style beers you may not want to use it for anything else. As stated previously if a vessel is cleaned and sanitized properly there is no reason to be concerned about cross contamination.
Another type of plastic container commonly used by homebrewers is the 5 gallon water bottle made of polycarbonate (PC) plastic. PC is harder and more rigid than HDPE and has about twice the gas permeability for both oxygen and carbon dioxide(17). As mentioned for HDPE this gas permeability may be of some advantage in the long term aging of lambic-style beers. PC being a plastic has the same perceived disadvantage as HDPE in that it can be scratched and thus harbor bacteria and wild yeast. PC has the advantage of being able to withstand boiling water without melting unlike HDPE. This allows one to thoroughly sanitize such a container since the whole vessel can be heated to a temperature that will kill all bacteria and yeast. This can be done using boiling water or an autoclave. Remember, be very careful when pouring boiling water into a container to avoid personal injury. PC is a clear plastic that allows observation of the fermentation process over time. This quality seems to be important for those first time lambic- style ale brewers who worry whether or not their beer is developing a pellicle or ropiness.
If one is careful to keep their plastic brewing vessels clean to start with then the more drastic measures such as boiling water or full strength bleach are not really necessary. A good general guideline is to always clean a vessel when you are done using it and then rinse it with a sanitizer before putting it away. For further information on cleaning and sanitizing materials please refer to these references (18,19).
Glass is generally considered by homebrewers to be the best material for fermenting beer for a number of reasons. It is very inert, easily cleaned, inexpensive and does not allow gas diffusion to occur. Also the clarity of glass allows one to observe the fermentation process and the various stages a lambic-style beer goes through over the course of time. Glass carboys of five to 7 gallon capacity will work just fine for producing lambic-style ales. Remember glass is fragile and large pieces of broken glass can inflict serious injury.
The impermeability of glass to gas diffusion is not likely to be as important in lambic- style beer production as it is for other types of beer. As stated before the traditional oak cask is far from absolutely gas impermeable. Also the fact that glass does not allow gas diffusion is made moot by the fact that studies show that in a vessel the majority of gas diffusion occurs through the closure and its sealing surface (i.e. stopper or lid), not the vessel walls (Personal Communication, Nalgene Technical Services).
Another material used by brewers is stainless steel, which has the advantages of inertness, strength and ease of cleaning. It is relatively expensive and completely opaque. Even if one has an extra pot or keg to ferment in, one must remember that it will have fermenting beer in it for a year or more and thus not usable for other purposes.
The advantage of an oak cask over other vessels is that it provides a microenvironment where the various yeast and bacteria can grow. This is due to the porous nature of the wood, which provides nooks and crannies for the microorganisms to inhabit.(20) The permeability allows the slow diffusion of air into the fermenting wort and this may further aid the growth of the microorganisms as well as flavor development. After a cask has been used for a number of batches it will become, one hopes, infected with the right microflora further aiding in the production of a more authentic product.
It also seems that as a cask is used for many years the various flavors from previous batches of beer as well as those from the yeast and bacteria build up in the wood and further add to the complex flavor profile of each successive fermentation. It is felt by some that even old oak adds a certain minor astringent note to the lambic from the remaining tannins that are slowly leached from the wood.
The homebrewer has to consider a number of things before obtaining an oak barrel. One has to consider the size, the type of oak (American or European), where to put it and whether to get a new or used one. First let's look at the type of oak barrel to buy. Regardless of whether you choose to buy a barrel made of American or European oak, make sure it is a wine barrel that is uncoated. Do not buy a whiskey barrel as they are charred on the inside and really only meant for making whiskey. Do you really want that burnt wood flavor in your lambic-style beer? Your best bet is to buy the barrel from a cooperage rather than through a homebrew supplier. That way you can get specifically what you want and also save some money.
It is generally felt that European oak is superior to American oak. This is based on the fact that American oak trees and European oak trees are different species (21). This leads to them having different profiles of the various compounds that are extracted during the fermentation process. The grain structure and thus porosity of the two species is also different. It is felt that American oak is too "oaky" as compared to European oak. There is some truth to this, but in the past few years things have changed (22). Part of the problem with too much "oakiness" in American barrels has to do with the way the wood is dried and aged. European cooperages have traditionally aged their wood for at least 2 years before it is used to make barrels. During this drying and aging process many of the oaky compounds are volatilized from the wood.
American cooperages on the other hand quite often oven dry the wood in a matter of days and then used it to make barrels. This leads to an over abundance of oak character left in the wood. Some cooperages still use this method for their less expensive barrels. Others have started to follow European practice and are aging their wood for extended periods. Unfortunately most of the cooperages in America that age their oak dont make barrels in any size less than 200 L. If you are looking for a barrel of 5-15 gallons you will probably have to do some calling around to see if you can find a barrel in stock made of aged wood. Small barrels are not kept in stock by many cooperages because demand is relatively small. Also it is no surprise that many of the cooperages are in California due to the large wine industry there.
Another factor to consider is the cost of European vs. American oak. The majority of European oak barrels come out of France and currently the franc is pretty weak. An investigation of prices for barrels revealed that most European barrels cost almost twice as much as equivalent American barrels. If cost is no object and you are in the market for a new wine barrel then of course go ahead and buy a barrel of European origin.
If you choose to buy an American barrel make sure it is a wine barrel. Again try to find one that is made from air dried wood, preferably of a year old or more. Also get the barrel with a medium "toast". This is a process where the insides of the staves of the barrels have been lightly browned but not charred as with a whiskey barrel. This is done to barrels that are destined for red wine production since it further reduces the tannins and oakiness of the wood. Since a barrel is a major investment ask to speak to a cooper about how to prepare the barrel. Ask what will be done if the barrel fails to hold water when you fill it. Will they exchange it for a new one? Most cooperages have people on staff willing to discuss how to prepare a barrel and are willing to provide an exchange for a leaky barrel. If you buy a barrel from reputable cooperage leaking should not be a problem anyway. Barrels come in a range of sizes starting at around 3 gallons and going up to 50 gallons or more. Typically though, European barrels do not come in sizes smaller than 25 liters.
If you choose to buy a barrel remember that it is going to have liquid in it for a year or more. It will need to be in an environment that does not freeze or exceed 80 F (27 C) as these are the general extremes in temperature encountered in Belgium. A barrel full of beer is going to weigh 8.3 lb./gallon of liquid plus the weight of the barrel. If you choose to buy a 10 gallon or larger cask think about the logistics of filling and storing it ahead of time. Due to the weight you may need a hoist or a few strong friends to lift it. Also be sure you have the brewing capacity to fill the barrel. It is not a good idea to partially fill the barrel. This may lead to drying of the staves and leakage.
The price of a barrel does not increase linearly with size. Typically a 10 gallon one is only about $20-30 more than a 5 gallon size. This holds true whether you buy American or European. Most of the cooperages selling American oak barrels designate the size by the gallon capacity whereas the dealers of European barrels designate size by the liter. This is just another point to consider when investigating a purchase.
Another source of barrels is previously used ones. Many wineries in the US use 200 or 225 Liter European barrels and you can pick them up for around $50 used. This requires you live near a winery and that you have the brewing capacity to fill it and the storage space. Many wineries only use the barrels for 3-4 years before selling them. The trend toward using barrels for a shorter time has come about due to the decreasing use of sulfites and the increased risk of Brettanomyces infection this can bring about. Thus you can get a barrel in really good shape for an excellent price. Unfortunately finding used barrels of smaller sizes is not so easy. Wineries and cooperages that deal in used barrels usually do not have anything other than 200- 225L sizes. It seems wineries do use the smaller sizes to keep wine in that is used to make up the ullage in the big casks. But they use these small casks until they are ready to be used as fire wood. So if you find someone with a used 5 or 10 gallon barrel for sale that is in good shape consider yourself lucky. Another source of used barrels maybe home wine makers who might be getting rid of a used cask. Finally note there is a company that is reconditioning the larger used barrels and downsizing them to 30 gallons. (See Barrel Supplier List)
Some people warn that any beer made in an American Oak barrel will taste like an oak branch. They also feel that it will take numerous batches of beer to extract all the oakiness from the wood. You will have to make a personal decision regarding American vs. European Oak. Regardless of what you buy you want the majority of the oak character removed from it prior to using it. The quality of a European barrel is not necessarily twice as good as an American one either. Any barrel, if well cared for will last for decades. To reduce the chances of oak beer you will want to buy either a used barrel or a new one that is made from air dried wood with a medium toast interior.
Regardless of the source any new barrel is going to have a certain degree of oak character that will be imparted to the beer. This is particularly true in the making of lambic-style beer, where the wort stays in the barrel for a long period of time. During this time period a great amount of chemical compounds can be extracted out of the wood. So it is suggested that you chemically strip the barrel. When you first get the barrel you will need to swell it with water to make it liquid tight. It is at this stage when you find out if the barrel is of good quality or not. At first you will need to top up the barrel daily as the wood swells and absorbs water. It may leak some at first, but should stop after 3-5 days. Once a good quality barrel has been swelled it should show no further signs of leakage unless damaged.
To maximize the amount of oak compounds leached out of the wood change the water in the barrel every three days for two weeks. This also ensures no mold will grow in it. If you live in an area that has high humidity you may want to add metabisulfite from the start at the rate of 200 PPM. After two weeks of soaking start the chemical stripping process to really remove the oakiness. This is done by adding sodium carbonate (washing soda) to the cask at the rate of 1/2 ounce/gallon and letting it soak for a week. Then drain the cask, rinse it well and repeat the process. To maximize the extraction repeat this process for 4 to 6 weeks. At this point the water in the barrel should be clear when drained as compared to the tan liquid when you start the process. Next neutralize any residual sodium carbonate by adding citric acid to the cask full of water to drop the pH to 3 and let it set for a few days. Then rinse it well and fill it with metabisulfite solution to inhibit mold growth until you can brew and fill it with wort.
Following this stripping procedure can help you reduce the chances of having multiple batches of oaky beer. If you get the right barrel and are careful to strip it thoroughly there is no reason not to use a barrel of American origin. Besides, even a European barrel will need to be stripped to some extent to reduce the oakiness that is present in any new unused barrel.
So now you have a barrel and it has been full of beer for a year or two and you want to bottle the beer. What do you do with the barrel once it is empty? First you should never leave a barrel that has held liquid empty for any period of time as it will dry out and shrink. This may lead to leakage that will not ever stop. Sometimes a leak can be stopped by hammering the steel bands of the barrel closer to the center. You will be better off if this can be avoided.
Since lambic-style beer takes so long to ferment and age, when you bottle is not very critical. You will be better off if you coordinate when you will empty the cask for bottling to a time when you can brew a new batch to fill the cask up again immediately. For example, the day you are brewing you can transfer the contents of the barrel to a carboy(s) or other holding vessel leaving as much of the lees behind as possible. This will allow the beer a chance to settle until you are ready to bottle anyway. Then you can rinse the cask out with water and have it all ready to fill when your wort is cooled. This way there is no chance of the cask drying out and all the microflora in the wood remain intact and happy. If you must empty the barrel and cannot fill it immediately, rinse it with water and burn a sulfur candle in it and bung it up tightly or fill it with metabisulfite solution. Then when you have time to brew rinse the cask well and fill it with wort.
A barrel is a major investment and can be ruined if it gets moldy on the inside. Thus it is important to keep it filled up close to the top at all times. This requires making up the ullage at regular intervals depending on the dryness of where you live. Also as previously stated, when there is not beer in the cask keep it filled with metabisulfite solution. Do not use bleach or iodophor as these would likely taint the wood and kill all microflora present in the wood.
The outside of the cask also requires regular attention. Again depending on where you live the outer surface may develop mold over time. You can spray the outside of the cask with metabisulfite at regular intervals or whenever you see signs of mold developing. Some people use a 200 PPM bleach solution or 25 PPM iodophor. These are probably OK to use as long as you do not saturate the wood with them. Others favor applying linseed oil to the outside of the cask. The important thing is to keep an eye on your barrels and treat mold and mildew infections when they develop. This is all part of taking care of a barrel so that it will last for years. It would be a shame to have a cask well infected with Brettanomyces and Pediococcus, ruined by mold.
Those of us in the US rarely have the luxury of being able to mix young and old lambic. So we have to make due with what works for our other brewing, that is using priming sugar of some sort. Of course if you do happen to have lambic-type ales of various ages fermenting then of course go ahead and try to blend and bottle them and see what you end up with. Gueuze, being refermented in the bottle is many times fairly highly carbonated, though there are examples that are nearly flat. This is part of the "Art" and variability of the process.
The problem with conditioning a beer in the bottle that has been fermenting so long is that the number of viable carbon dioxide producing organism may be very low. If this is the case the beer may not become carbonated or only very lightly. To combat this problem you may want to prepare a fresh starter of Brettanomyces and/or Saccharomyces at the time of bottling. Then you want to prime with enough sugar to end up with a fairly carbonated product.(2.5-3 volumes CO2) Using a cup of corn sugar can lead to adequate carbonation after as little as two months. Other times there may be little carbonation after two years. It would not seem to be a good idea to add Saccharomyces at the time of bottling since they do not survive through the lambic fermentation process.(12) But those of us who have looked at what is in the sediment of a recent Boon lambic have discovered that the only yeast generally recoverable is indeed non-cyloheximide resistant yeast, most likely Saccharomyces. Boon fines his old lambic before adding the young beer and in the early stage of the ferment Saccharomyces is the dominant strain. Limited testing indicates that this yeast is indeed acid and alcohol tolerant.
As with other aspects of this type of brewing, and with all homebrewing for that matter, you have a great deal of latitude with bottling. There are some things you should keep in mind though when you are considering transferring your beer from the fermentation vessel to bottles or other serving containers. If the beer has been fermenting for a year or longer the viability of the microorganisms in the beer may be low and/or may be predominantly bacteria and not yeast. If the viability of the yeast is low and you choose to bottle the beer unblended with corn sugar then you may get little carbonation of the product. If the predominant microorganisms present are bacteria then they will utilize the sugar before any yeast and again you will get little carbonation. This is because the predominant bacteria in an older lambic-style ale will most likely be of the homofermentative variety.(i.e. Pediococcus) As described elsewhere, homofermentative bacteria do not produce gas as they metabolize sugars. Again you can possibly combat this problem by adding a fresh starter of Brettanomyces along with a heterofermentative lactobaccilus. Apparently there is a symbiosis between the yeast and bacteria that can aid in carbonation.
You can choose to put your beer into bottles using other traditional techniques or standard homebrewer methods. You can also put your beer into kegs or other containers that can be artificially carbonated, such as PET bottles using a Carbonater (TM) or TAP-CAP(TM). You can also naturally condition your beer in a keg and then serve it using CO2. The choice is up to you and you need to make some decisions regarding what you ultimately want to achieve.
Lets start with bottling, as it is still the traditional technique used by lambic brewers in Belgium. As stated before, as long as beer is fermenting in a vessel it is called lambic. When it is bottled and refermented it becomes gueuze or one of the fruit flavored derivatives. Of course we are not making real lambic, gueuze, Framboise or Kriek since our product does not meet all of the qualifications of an authentic product. To make a gueuze-like product the beer needs to be put into bottles and refermented in a fashion not unlike standard homebrewing practice.
If the beer is fairly old and has a thick pellicle of yeast on the top and a large layer of yeast at the bottom of the vessel then you may want to consider racking the beer. Transfer the beer to another vessel, being careful to leave as much of the top and bottom layers behind as possible. Then you can let this beer settle for a week or so prior to bottling. This technique allows you to minimize the amount of sludge carried over into the bottles. Of course you do not want a completely yeast free product as it will then fail to referment in the bottle after priming. As stated before one can run into problems with lack of viable microorganisms in the beer. In a best case scenario the beer will still have adequate numbers of viable yeast even after settling. In that case you simply transfer the beer once again to a bottling vessel and add corn sugar (enough to reach 2.5- 3 volumes CO2). Bottle it and wait for it to condition. Sounds simple, but unfortunately lambic-style beer making does not always lend itself to simplicity, especially when you are trying to make a product with good flavor complexity.
At the Boon Brewery things are done a little bit differently. Frank Boon has a slightly different view of the world and wants a more consistent product that has good keeping qualities and a good appearance. To this end Boon gueuze is made by blending old beer that has fermented at least two years with very young beer that has only been fermenting a few weeks. They are blended at a ratio of 95:5 respectively. Boon also clarifies the old beer prior to blending. This gives a bottled product that is reasonably clear and does not develop ropiness. The blending technique requires that you use your hydrometer to determine the extract in the old and young beer and then mix them accordingly. (7,9). Then you bottle the mixture and hope for the best. This technique requires that you have more than one batch of lambic-style beer going at a time.
Using the fresh starter approach can still cause problems if there is a large amount of bacteria in the beer at bottling. They may consume the sugar before the yeast and thus little or no carbonation will develop. To alleviate this problem one can remove the bacteria by filtering the beer prior to bottling at the 0.2 micron level. Then all you need to do is add fresh yeast and sugar. Alternatively you can prime with DME since it contains more than glucose, the only sugar that the bacteria can utilize. The bacteria will consume the glucose and then the Brettanomyces will consume the remaining sugars and dextrins and carbonation will develop. Or at least that is how it should work in theory.
One can use the blending approach, but instead of using young lambic you can use a standard ale that has been very lightly hopped, if at all. You can measure the gravity of the standard ale and the lambic-style ale and then blend in the right ratio to give you enough extract to achieve carbonation. As with the other techniques you can add a fresh starter of Brettanomyces to aid in adequate carbonation.
Homebrewers have at their disposal another source of dextrins to use for priming in the form of maltodextrin powder. This powder contains little glucose and maltose and will eventually be hydrolyzed into fermentable sugars by the Brettanomyces cellular enzymes. Standard priming rates can be used for maltodextrin since it will ultimately become primarily fermentable sugars given enough time.
One could use any combination of the above when bottling. There is a great deal of experimentation left to be done in this area of lambic-style ale brewing. Keep in mind that lambic microorganisms grow slowly and it may take months or even years for the product to reach equilibrium. Lambic, unlike most other beers, continues to change for the better with age, quite often becoming more complex and less harsh. The key to lambic ale brewing is to be patient and go ahead and start other lambic ales and allow them to age. In a few years you may be rewarded with a very nice complex product and then again you might not. The important thing to keep in mind is that as a lambic-style ale referments in the bottle chemical reactions are occurring that lead to various flavor changes. These reactions occur at a fairly slow rate, since many of them are catalyzed by enzymes from Brettanomyces. Remember Brettanomyces grow slowly and never reach very high concentrations in the fermenting beer or in the bottle. This is one of the reasons why it takes lambic ales so long to ferment and for proper flavor development to occur in the bottle. Be patient!
Brewers in Belgium have a distinct advantage when it comes to bottling their beer and achieving the right flavor. A typical lambic brewery has many casks with lambic in them from which the brewer can choose. This allows the brewer to achieve the right flavor complexity and balance in his product. If a barrel contains lambic that is too hard it can be blended with softer lambic to achieve the right flavor. The typical homebrewer does not have this option available to him or her. Usually a brewer has one five gallon batch going which is then bottled. Depending on many factors the single batch may end up being too hard or too soft in character. As a brewer you have a number of options. You can brew lambic-style beer on a regular basis and thus over time (years !) have enough lambic on hand to allow you to blend. The other approach is to ferment a 5 or 10 gallon batch in one gallon bottles and hope the resulting beers all differ in character to some extent.
Quite often none of these approaches is practical for a homebrewer. But I will remind you that making lambic-style beers is not about being practical or making beer in the easiest manner. One must make a decision based on what he wants to achieve when making this type of beer and how many sacrifices one is willing to make in order to achieve a product that has any of the flavor and complexity of the real thing. The choice is up to you.
The enterobacteria that have been found to be present in lambic beer include Enterobacter cloacea, Klebsiella pneumoniae, Escherichia coli, Hafnia alvei, Enterobacter aerogenes and Citrobacter freundii. These are gram-negative straight rods which are motile with the exception of Klebsiella. There can also be non-motile variants of the other species. They all are able to ferment glucose with some producing gas while others do not. Most of them grow quite well in the presence of air and are also able to ferment lactose. These bacteria follow either a butanediol fermentation pathway or a mixed acid pathway. This leads to large amounts of lactic (~1500 ppm), acetic (~600 ppm) and succinic (~275 ppm) acids along with 2,3 butanediol (~2000 ppm) being formed in the first month of the fermentation (10, 23). They can reach levels of 1 X 108 cells /ml during the first 30-40 days of the fermentation. After this period the decrease in pH and the increase in alcohol caused by yeasts of the Saccharomyces species causes them to die off.
The various by products from the growth of the enterobacteria can lead to various flavors described as celery-like, parsnip-like, mushroom-like, smoky or mouldy (10). These flavors are not removed by the fermentation process. The various acid products described previously also have an impact on the beer flavor contributing to the acidic taste of the final product. In fact the majority of acetic acid found in lambic beer originates in the first month and is the byproduct of enterobacterial growth.
Typically enteric bacteria are considered pathogenic (disease-causing) in humans. They are often considered the cause of various forms of food poisoning. This is indeed the case, with Salmonella being cause of the vast majority of cases (24). The enteric bacteria found in lambic are generally not considered pathogenic in people other than those who have immune systems that have been compromised in some way (i.e AIDS or immunosuppresive chemotherapy).
Research has shown that the kitchens of many peoples homes harbor more enteric bacteria than their bathrooms. (24) These bacteria include all those found in lambic along with Salmonella. Meats, vegetables and kitchen sponges or wash cloths have all been found to be highly contaminated, with the later having particularly high bacterial counts. This makes the kitchen an ideal environment for allowing the introduction of enteric bacteria into ones wort.
Discussions among homebrewers about making lambic-style beers have also avoided the subject of enteric bacteria. This has been due to the fear of food poisoning and the associated side effects. Again research would indicate that anyone who brews in their kitchen does indeed end up with some amount of enteric bacteria in there beer. The growth of the brewing yeast and the subsequent reduction in pH and increase in alcohol kill the bacteria off before they can cause off flavors or other problems in the majority of cases.
It can be argued that without enteric bacterial growth and the subsequent depletion of glucose and production of metabolic byproducts lambic would probably not have the depth of flavor and complexity that it does. Because homebrewers have been "afraid" of enteric bacteria they are missing an integral part of the production process. Studies indicate that the enteric bacteria have a profound effect on the subsequent growth and flavor development in real lambic. In order to achieve the same flavor profile it would seem important to have this initial growth of these bacteria.
In order to allow the wort to become infected with enteric bacteria a reasonable approach would be to leave the fermenter open near a kitchen sink for an hour or two after the wort has cooled. Then the brewer should wait an additional 24 hours before adding any yeast. This will allow the enteric bacteria to gain a foothold and begin to grow and multiply to a level that allows them to produce a significant amount of metabolic byproducts and deplete the glucose. After 24 hours the addition of a small amount of yeast will ultimately lead to the enteric bacteria being killed off. Again because the yeast will produce alcohol and lower the pH of the wort to a level at which the bacteria can no longer survive.
Brettanomyces have the ability to form acetic acid from glucose under aerobic conditions. Thus when they grow on calcium carbonate agar there is a visible zone of clearing around the colonies. They demonstrate a negative Pasteur effect. That is they demonstrate a higher production of alcohol under aerobic conditions as opposed Saccharomyces which show decreased alcohol production under aerobic conditions (27). Brettanomyces also have cellular dextrinases that allow them to utilize dextrose polymers larger than the typical trisaccharides that can be utilized by Saccharomyces. A culture of Brettanomyces has a characteristic acetic, earthy, horsey aroma. These yeast grow much more slowly than do Saccharomyces brewing strains. Also they are resistant to cycloheximide unlike most normal brewing yeasts. Brewers classify Brettanomyces as "wild" yeast and typically do all they can to avoid them. In normal brewing these yeasts will lead to various off flavors described as phenolic, smoky and goaty. In lambic beer these are desired characteristics.
Another aspect of Brettanomyces is their ability to enzymatically catalyze the formation of esters from the corresponding alcohol and acid. Thus ethyl alcohol and acetic acid can be combined to from ethyl acetate and lactic acid and ethanol can be combined to form ethyl lactate. These are two of the primary esters found in lambic beer (28, 29).
Any type of Saccharomyces can be used for the primary fermentation of a lambic- style beer, since it will contribute little if anything to the overall flavor profile of the finished product. One can find any number of articles and books on how to culture these yeast and maintain them in the home brewery. (25, 26, 30, 31, 32)
It is the other organisms involved which are more difficult to culture and maintain without some experience and knowledge of how they grow. The yeast of the Brettanomyces species bruxellensis and lambicus and the bacteria Pediococcus damnosus are microorganisms that require very specialized nutrients and environmental conditions. It should be noted that unless you are going to brew lambic-style beers more than once or twice a year you may be better off buying new cultures each time rather than trying to maintain them in a home environment. If you do feel the need to maintain the cultures at home then you should become very familiar with the culturing of normal brewing yeast first.
Both Brettanomyces and Pediococcus produce acids as normal
metabolic by- products and because of this they need to be
maintained on media which can help neutralize it.
Otherwise, the acid will lead to a large drop in pH and the
organisms will die. The most readily available food grade
acid neutralizing agent is calcium carbonate (CaCO3), also
called precipitated chalk. A concentration of 2% (2 g/100
ml) in the growth media or agar will provide adequate
buffering capacity. Calcium carbonate is essentially
insoluble though and this can present problems if it is used
in making wort agar. To prevent the CaCO3 from falling out
of solution before the agar solidifies, cool the wort-agar
solution to 113-122 F (45-50 C), with constant swirling,
prior to pouring it into the tubes or dishes. When CaCO3 is
used in liquid media one can gently swirl the media with
the culture growing in it once or twice a day to help
prevent any stratification of the acid in the solution and
aid the neutralization of it with the CaCO3. As the lambic
organisms grow in the liquid media the acid produced will
react with the CaCO3 causing it to be solubilized over time.
Even when a culture reaches maximum confluence there may
still be some CaCO3 unneutralized, but this is not anything
to worry about as the acid produced by the growth in the
main wort will dissolve it in time.
The Brettanomyces yeast can be grown on wort agar which
incorporates 2% CaCO3 as noted previously. The wort itself
should be of a gravity of approximately 1.040 and
preferably made from an all grain wort due to the possible
lack of nutrients in malt extract (5,6). Due to the
fastidious nature and acid production by Brettanomyces they
need to be transferred to new slant more often than do
Saccharomyces. It is recommended they be transferred to new
slants at least every 2 months. Longer intervals between
transfers may lead to cultures which are no longer viable.
Because of this frequent manipulation there is a greater
chance the yeasts themselves may become contaminated with
other yeast, mold or bacteria. Thus your sterile culture
technique needs to be very good and you need to pay
attention to details. If your culture does become
contaminated you can prepare a dilute suspension of the
yeast and streak it out on a petri dish which has wort agar
with 2% CaCO3 and also incorporates 10 ug/ml cycloheximide.
(Appropriate cautions inserted) As the colonies grow watch
for a zone of clearing around the individual colonies.
Agar prepared with calcium carbonate will be opaque and
white in color and as the Brettanomyces grow the acid they
produce will dissolve the calcium carbonate and create the
zone of clearing. Generally only non-Saccharomyces yeast
will grow on media with cycloheximide in it and those that
do grow and have zones of clearing around them are likely
to be Brettanomyces. You can then pick the colonies off
and re-culture them on cycloheximide-free media. This is by
no means a definite technique for the isolation and
characterization of Brettanomyces. Yeast such as Kloeckera
are also acid producers that will grow on cycloheximide
agar. If you have doubts at all then you may be better off
buying new cultures and/or locating a microbiologist who
will work for homebrew. The only absolute way to
characterize a culture is through extensive fermentation,
assimilation and morphological testing, dont believe it if
someone tells you otherwise.
Pediococcus is more difficult to grow and maintain than is
Brettanomyces due to its more complex nutritional and
environmental requirements. Pediococcus grows best in
liquid rather than solid media and this increases the
chances for unseen contamination. Unless you have access
to a 1000X power microscope and have culturing experience,
it is recommended that you do not try to maintain this
bacteria at home for any length of time. MRS (deMan,
Rogosa and Sharpe) broth is the preferred media for growing
and maintaining Pediococcus over long periods. It is a
defined media that is rather expensive but provides the
necessary nutrients and buffers for optimal growth over
extended periods. Prepare the media as indicated on the
package. Sometimes bacteria can lose their hop resistance
if grown in unhopped media for extended periods. Thus if
you are going to try to keep cultures going over a period
of time it is suggested you add iso-alpha acids to the media
using some type of hop extract. Use of whole or pellet hops
leads to particulate matter which causes the media to
become cloudy and less than ideal for visual monitoring of
growth. A suggested level is in the 15-25 IBU range. A
minimum suggested passage interval is every month. Allow
the culture to grow for a week at room temperature and then
it can be stored at 4 C. Another method for storing
Pediococcus is the use of stab cultures. MRS media is
prepared using 1.5 % agar and put into tubes. The tubes of
solidified media are inoculated by using a needle or
inoculation loop to stab the bacteria into it. The
bacterium is allowed to grow at room temperature for a week
or so until signs of growth can be seen. Then the tubes
can be stored at 4 C. Whether you use liquid or stab
cultures you need to keep the tube caps screwed down tight
to limit air diffusion into the cultures and prevent
desiccation. There is no need to worry about pressure
buildup since Pediococccus are not gas producers. The same
caveats apply to bacteria culturing as for lambic yeasts:
you need the proper equipment and good technique.
If you are going to get serious about culturing
microorganisms used for lambic-style beers then you might
consider buying or building a laminar flow hood of some
type. This will allow you to work in a nearly sterile
environment. Fungi Perfecti is one of several companies
that sell them or you can build your own. (33)
Due to the additional vitamin requirements of Pediococcus
you may want to add 10% apple or tomato juice to the wort
starter. Another alternative is to use 0.5% dried brewers
yeast. Yeast extract is even better due to its purity and
solubility, but it is expensive. Wort from a previous
brewing session with 0.5% yeast extract added works very
well. This gives a nice clear media in which one can
monitor the growth of the bacteria more easily. As the
bacterium reaches confluence a clear zone will develop at
the top of the liquid and the rest of the liquid will be
very cloudy due to the large amount of bacteria.
For other beers you want to pitch a large volume of yeast to
ensure a rapid fermentation and decrease the risk of
contamination by wild yeast and bacteria. Well,
lambic-style beers require you to throw caution to the wind.
Large starters of normal ale yeast, Brettanomyces and
Pediococcus are not required. If the yeast and bacteria
are healthy there is no reason they should not grow in the
wort using the small volumes as described previously.
Remember this beer will be in a vessel for a year or more
and the bacteria and yeast have plenty of time to grow.
Also as the acid producing strains grow they will kill off
any other organisms due to the lower than normal pH,
increase in alcohol and reduction in sugars that are
fermentable by other organisms. If you feel the need to
use larger starters to put yourself at ease then by all
means go ahead. Just remember the beer will still take a
year or so to develop the proper character.
Whether you choose to culture your own lambic microorganisms
or buy them, you will need to propagate them prior to
adding them to the wort. A wort of specific gravity 1.040
with 2% CaCO3 will work just fine for this purpose. You
may also want to add some hops, to achieve a range of 15-25
IBU. You should follow a scale up procedure for these
microorganisms so as to reduce the risk of other organisms
over growing the cultures. With lambic cultures one does
not have to make as large a starter as that used for normal
beer. Start with a volume of 1/4 ounce (~5 ml) and allow
the culture to reach confluence. When it has, add the
contents to a volume of 4 ounces (~100 ml) and allow it to
again reach confluence. At this point you can pitch or
scale up one more time to a volume of 1 pint (~450 ml).
Such procedures have also been outlined elsewhere (30, 31,
32). Be aware that Brettanomyces is a very slow grower as
compared to other yeast and generally does not develop a
large kraeusen head either. The starter should develop a
typical Brettanomyces aroma due to the various fermentation
byproducts. You should notice a distinctive acid aroma
along with aromas often described as horsey or mousey. The
starter will also develop an acidic, mousey, earthy taste
if the yeast is indeed Brettanomyces. As the yeast grows
the acid produced will cause the CaCO3 to dissolve and the
fine white precipitate from it will mostly disappear.
Because lambic-style beers are not widely brewed the
Brettanomyces yeast and Pediococcus bacteria are not always
available on the shelf at your neighborhood homebrew shop.
The other reason for limited availability is that these
cultures do not maintain viability for as long a period of
time as do more traditional brewing yeast. Both the
Brettanomyces and Pediococcus are acid producing organisms
and this causes them to literally kill themselves off when
stored for extended periods. Also the organisms are
extremely fastidious, meaning they have complex nutritional
and environmental requirements and cannot be maintained in
static storage for long periods.
Due to the additional vitamin requirements of Pediococcus you may want to add 10% apple or tomato juice to the wort starter. Another alternative is to use 0.5% dried brewers yeast. Yeast extract is even better due to its purity and solubility, but it is expensive. Wort from a previous brewing session with 0.5% yeast extract added works very well. This gives a nice clear media in which one can monitor the growth of the bacteria more easily. As the bacterium reaches confluence a clear zone will develop at the top of the liquid and the rest of the liquid will be very cloudy due to the large amount of bacteria.
For other beers you want to pitch a large volume of yeast to ensure a rapid fermentation and decrease the risk of contamination by wild yeast and bacteria. Well, lambic-style beers require you to throw caution to the wind. Large starters of normal ale yeast, Brettanomyces and Pediococcus are not required. If the yeast and bacteria are healthy there is no reason they should not grow in the wort using the small volumes as described previously. Remember this beer will be in a vessel for a year or more and the bacteria and yeast have plenty of time to grow. Also as the acid producing strains grow they will kill off any other organisms due to the lower than normal pH, increase in alcohol and reduction in sugars that are fermentable by other organisms. If you feel the need to use larger starters to put yourself at ease then by all means go ahead. Just remember the beer will still take a year or so to develop the proper character.
The following is a list of suppliers both retail and wholesale who are known to carry the cultures and/or the culturing equipment and supplies needed to grow and maintain these organisms. No endorsement is made for any particular company.
Advanced Brewers Scientific 3034 SE. 20th 2233 Sand Rd. Portland, OR 97202 Port Clinton, OH (503) 234-7503 (419) 732-2200e-mail firstname.lastname@example.org
409 Calle San Pablo #104
Camarillo, CA 93012
1 (800) 827-3983
They carry both Brettanomyces and Pediococcus and a line of culturing equipment and other supplies for the homebrewer wanting to do their own culturing.
P.O. Box 331058
Detroit, Michigan 48232
1 (800) 521-0851
They do not sell direct, but only through distributors. When you call request a catalog and the name of your local distributor. They are an excellent source of media and chemicals needed for the growth and isolation of both yeast and bacteria of all types. I have had no problems buying from my local distributor. Be prepared for sticker shock when you see the catalog though.
P.O. Box 7634
Olympia, WA 98507
Fungi Perfecti is a company that sells supplies and equipment for culturing mushrooms. Because cultivation of mushrooms requires sterile technique they sell a wide variety of laboratory supplies and equipment that are also useful to the homebrewer who does his or her own yeast culture. Note their catalog is not free but the price is deductible from the first order. They also have a page on the WWW.
HeadStart Brewing Cultures
256 Cherokee Rdg.
Athens, GA 30606
This company has Brettanomyces strains of various origins as well as Pediococcus and other yeast and bacteria for brewing non-traditional beers. They also have various culturing supplies and media.
319 1/2 Millburn Ave.
Millburn, NJ 07041
This is a homebrew shop that carries bottle caps and a capper that work with European champagne and lambic bottles.
The Yeast Culture Kit Company
They carry Brettanomyces and Pediococcus as well as all the necessary culturing supplies needed to grow these organisms and can also supply specialized growth media upon request.
Wyeast Labs and G.W. Kent sell wholesale only, but you can obtain their products through your local homebrew supplier. Wyeast sells a yeast that carries the designation #3278B (previously 3278 Brettanomyces Bruxellensis). G.W. Kent sells a strain of Brettanomyces and a strain of Pediococcus through their Yeast Lab division.
Regarding the Wyeast 3278B and its composition, the company sent the following letter to retailers:
Sept. 5, 1995
Dear Valued Customer,
re: 3278 Yeast
Please provide this notice to all customers of: Brewers Choice #3278B Yeast.
This name change reflects the fact that this yeast is a blend of yeasts and not 100% of one particular strain. The product has not changed; as many of you know, certain Belgian beer styles require more than one yeast to make a good beer. For several years we have produced this blend, because using 100% of one yeast would make an unpalatable beer. This item will remain available with a modified label as indicated.
We are sorry if this has caused any inconvenience. Please call or write use if you have any questions or comments.
Sincerely, Dave Logsdon.
Barrel Supplier List Note: The first four suppliers on this list carry barrels in smaller sizes (i.e., 5-7 gallons or the metric equivalent) The other suppliers may or may not have barrels smaller than 200 liters. Napa Fermentations carries both European and American Oak barrels. Independent Stave makes only American oak barrels. Both Demptos and Seguin Moreau carry only European oak barrels. This information is believed to be correct at the time of this writing. Typically a European oak barrel will cost twice as much as an American equivalent and the price you pay will also depend on the current exchange rate for foreign currency.
You will find that the cost of a barrel does not increase in a linear fashion with size (i.e. a 10 gallon barrels does not cost twice as much as a 5 gallon) So it pays to shop around and decide what your needs are really going to be.
If you are considering making really large batches you can pick up used 200-225 L barrels from wineries for around $50. Smaller sizes are nearly impossible to find used because wineries use them to hold wine for topping up the big casks and use them until they are ready to be used as fire wood.
Napa Fermentations (707) 255-6372
Demptos Napa Cooperage (707) 257-2628
Independent Stave Co. (417) 588-4151
Seguin Moreau Cooperage (707) 252-3408
Tonnellerie Vicard (707) 257-3582
Tonnellerie Radoux (415) 457-3955
Tonnellerie Francaise (707) 942-9301
Tonnellerie Mercier (804) 493-9186
Les Tonnelleries de Bourgogne (707) 257-3582
Stefanich (415) 665-1885
Stavin (415) 331-7849
Pradel Barrels (707) 944-8720
Mel Knox Barrel (415) 751-6806
Custom Cooperage (707) 996-8781
Cork Associates (707) 224-6000
Boswell Co. (415) 457-3955
Blue Grass Cooperage (415) 331-5734
Barrel Builders (707) 942-4291
Barrel Specialties (707) 553-9707
Specialize in reconditioning used barrels. They have 30 gallon barrels available and will ship.
Minimum order is one (1) 42 pound package of fruit. They do not except VISA or MC, payment must be in advance. They carry Strawberry, Red Raspberry, Blueberry, Marion Blackberry, Boysenberry, Bing Cherry, Purple Plum, Red Tart Cherry, Peach and Black Raspberry.
Variability of Fermentation SOFT HARD ROPY Alcohol (g/100 ml) 4.61 4.55 4.6 pH 3.9 3.4 3.5 Real Extract 1.018 1.015 1.019 Ethyl Acetate (ppm) 30.1 539.8 12.2 Propanol 9.2 8.7 5.0 Isobutanol 18.8 15.4 7.0 Butanol <0.1 <0.1 <0.1 Isoamyl Acetate <0.1 <0.1 <0.1 D-amyl Alcohol 15.6 11.4 9.0 Isoamyl Alcohol 57.9 53.1 39.5 Ethyl Lactate 21.9 140.3 79.0 Phenethyl Alcohol 45.8 38.1 64.0 Acetic Acid 766 3994 530.0 Lactic Acid 492 3677 13446All beers were from the same brewery. The "soft" and "hard" beers were both from the same batch of wort and were 9 months old. The "ropy" beer was 6 months old. Reference (14).
Figure on Page 75 in Lambic A discussion
This figure illustrates a number of important points with regard to the production of lambic beer. First of all it should be pointed out that the data represented here all came from one lambic brewery and was collected 20 years ago. It does not necessarily represent the fermentation process in all lambic breweries in Belgium. But it does provide some very good insight into what occurs in lambic over time. Remember that all the organisms that are present in lambic are introduced when the wort is cooled and transferred to the casks. No pure culture additions are made at anytime.
During the cooling process microorganisms enter the wort from the brewery environment. The view that they are blown in on the night air and that the Senne Valley is the only place in the world where a spontaneously fermented beer like lambic can be produced is a somewhat silly romantic notion that has been shown to be basically untrue. Dr Verachtert has written "...the special microclimate of the river Zenne accounts for the special mysterious microbial flora necessary for lambic brewing." Translated into scientific terms this means that the brewery environment has become a source of appropriate micro-organisms and that lambic can be brewed at other locations provided the brewer is prepared to enter a long period of trial and error. All the yeast and bacteria are already in the brewery and fall into the wort more than likely attached to dust and dirt particles. Insects, particularly flies and the occasional bird are also responsible for "inoculation" of the wort. Another source of microorganism is the pipes used to transfer the wort from the coolship to the mixing tank and from the tank to the fermentation casks. And finally the cask themselves harbor bacteria and yeast since they are never really sterilized between uses. Typically the only treatment barrels get is a good hot water rinse, a scrubbing with chains and then a sulfur candle is burned in them to inhibit molds.
By the second or third day the fermentation process is well underway with foam being produced by the metabolic activity of the enteric bacteria. These bacteria as stated before are primarily responsible for the acetic acid in lambic. As you can see the acetic acid reaches a constant level in a few weeks, showing no further increases. At the same time yeast of the species Kloeckera apiculata begin to grow as well. The combined metabolic activity of these microorganisms consumes most of the available glucose and free amino acids.
After about two weeks the Saccharomyces species begin to overgrow the wort. Their growth seems to be delayed partially because the enteric bacteria and Kloeckera apiculata have consumed most of the readily available nutrients. The enteric bacteria further hinder the growth of the Saccharomyces through some as yet unknown mechanism. Once the Saccharomyces begin to grow they produce ethanol and lower the pH of the wort and this leads to the enteric bacteria and Kloeckera being killed off. The Saccharomyces are responsible for the main alcoholic fermentation. They dominate for about 3-4 months and then their numbers begin to slowly decline. This decline is primarily due to the increase in acidity brought on by the growth of lactic acid bacteria and Brettanomyces yeasts. The Saccharomyces seem not to be able to survive the combination of ethanol, acetic and lactic acids.
At three to four months lactic acid bacteria of the species Pediococcus damnosus become the dominant microorganism in the wort. This increase in growth coincides with the increase in temperature that occurs at the onset of spring and summer. The increase in temperature is important, for otherwise the bacteria will not proliferate and the subsequent acid production will not occur. This proliferation of the lactic bacteria can be seen occurring with each summer the wort is in the cask.
At times the lactic bacteria reach very high levels and the wort will become "ropy". This is due to exopolysaccharides that the bacteria produce and causes the wort to become viscous and stringy. Though it is visually unappealing it is completely harmless. It seems that subsequent growth of Brettanomyces leads to the slime being broken down and disappearing. The lactic bacteria are an integral part of the lambic fermentation leading to the large amounts of lactic acid found in the beer.
After about seven to eight month the lactic acid bacteria have declined and yeast of the species Brettanomyces begin to take over. For the remainder of the fermentation period these are the dominant yeast found in the beer. They have the ability to hydrolyze dextrins and thus breakdown the remaining polysaccharides in the wort.
The Brettanomyces yeast are responsible for many of the chemicals found in the beer and the characteristic flavors and aromas they lead to. As already discussed these include ethyl lactate, ethyl acetate and the various organic acids such as caprylic, capric and caproic acid along with a number of other chemical compounds. It is the combination of these many compounds that add to the overall flavor complexity of a fine lambic.
As with the lactic bacteria the Brettanomyces yeast grow very slowly and never reach very high numbers. Also due to their ability to form branching structures they can float and form a pellicle on the top of the fermenting beer. It is felt that this film helps protect the beer from subsequent oxidation over the long fermentation period.
An important point indicated by the graph is that by 12 months the beer has come close to being at steady state. That is the levels of alcohol, acetic and lactic acid, and ethyl acetate have reached constant levels. After the first year what then occurs is that various other compounds are either produced or converted and any remaining polysaccharides are broken down. This a very slow process due to the fastidious nature of the microorganisms. The process is further inhibited by the unfavorable environmental conditions of very low pH and high alcohol that inhibit the enzymes of the yeast and bacteria. Once the beer is put into the bottle these changes and chemical reactions continue to occur but again at a very slow rate. This is why lambic beer takes so long to ferment and develop in the bottle. The take home message is to be patient and not try to rush things.
What really is it that makes a good lambic? Lambic, gueuze, fruit varieties Extract approach and all grain approach Discussion of Blending and its effect Who drinks lambic and why.
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