A Silk Purse from a Sow's Ear

or How to Make pLambics for Fun and Profit

by Jeremy Bergsman

Worts of Wisdom meeting March 29, 1995

Making a p(seudo)lambic is just like making any other beer except that it is completely different.


This talk and these note are based solely on my own research and do not reflect any practical experience on my part, which is to say, I haven't yet tried to do this.


The grist consists of 60% pale malt, preferably pilsener malt, and 40% unmalted wheat, with some people claiming that soft white wheat is better than hard red wheat. The important reason for the use of unmalted wheat will be explained below, under mashing and again under fermentation. Enough to achieve an OG of 1.045-55 should be used.
The hops used need to be devoid of any aroma or flavor. They are chiefly used for their antibacterial properties which apparently survive oxidation. Large amounts of hops are used, typically 3-6 ounces per 5 gallon batch. I think it is safest to stick with noble types (Hallertauer, Saaz, Tettenang, etc.). Anyone wishing to try this should ask me, I have a good collection of (formerly) good hops aging in paper bags in my kitchen. The hops are boiled the entire time, ensuring that no flavor is passed on.
Use fairly soft water. The Hetch-hetchy water most people have around here is good.
Here is where things get wacky. Real lambic makers innoculate their wort by allowing it to cool overnight in shallow, open vessels in front of open windows in dirty breweries. This can only be done (as far as anyone knows) in one part of the world. Elsewhere people make plambics. The p can stand for pseudo or pure strain since this is the approach that must be taken when your air does not carry the right stuff. For example, here is a list of microorganisms that Mike Sharp put into one batch of pLambic that he made last year: As you can see, he has obtained his bugs from bottles of lambic (Cantillon), national culture collections (NRRL and ATCC), and elsewhere.

The bugs used generally fall into four genera: Saccharomyces, Kloeckera, Brettanomyces, and Pediococcus. Other types are also found in real Lambics but these are not considered to be as important. Saccaromyces is the genus that includes bread and beer yeast, S. cerevisiae, which is the major species of Sacc. found in Lambics. The genus Kloeckera (a yeast) has one major species involved in Lambic fermentation, K. apiculata. Brettanomyces (I will abbreviate this Brett.) is represented by three species, B. lambicus, B. bruxellensis, and B. clausenii (hard to obtain but Frank Boon thinks it is more important than the others). The Brettanomyces yeasts contribute a lot of the uniquely lambic flavors to these beers, the so-called "horsey" or "mousy" flavors. Pediococcus (Pedio.) is a genus containing a few lactic acid generating species of bacteria, most importantly P. cerevisiae.

Wort Production:

The fermentation is where the lambic characteristics are generated. In order to have a successful fermentation where several different types of microorganisms are going to do their things over a two year period, the wort composition is very important. There are three unusual features of the wort compared to other beer worts: 1) high starch content, 2) high amino acid content, and 3) high levels of hop antibacterial agents. The first two are important to provide the proper growing conditions for the Brett. Why this is will be explained below. The high antibacterial levels control the growth of both wanted and unwanted bacteria.

The high starch content is provided by the use of unmalted wheat, which contains a lot of undigested starch, and by the use of an unusual mashing technique. Sometimes called the turbid mash, this can be thought of as a badly done decoction mash. In the mash there is a solid portion (the grain) and a liquid portion. There are also two key types of players, the biological polymers (starches and proteins) and the enzymes. The enzymes are associated with the liquid portion of the mash and the starches and proteins are associated with the solid portion. In a decoction mash the solid portion is removed, heated (aiding solubilization of its components), and added back, sparing the heat-sensitive enzymes from damage. In the turbid mash essentially the opposite pattern is followed: the liquid portion is drawn off, heated, and returned to the mash. This severely limits the degradation of the starches. Extra hot sparge water may be used to extract extra starch and tannins.

When the mash is complete, the sweet wort produced is boiled a very long time (3-6 hours). This breaks down the proteins, releasing amino acids into the wort. During this long boil the hops are releasing their antibacterial agents into the wort.


The fermentation is the most complicated part of understanding lambics, and is probably the most important variable in making good plambics. The lambic wort is "pitched" with very small numbers of lots of different bugs. The fermentation that follows is a result of the mixture that inoculates the wort, the composition of the wort, and symbioses between the various bugs.

Things begin with enteric bacteria and K. apiculata. These consume all the glucose in the wort, produce ethanol, and lower the pH, all tending to prevent further bacterial growth. The K. apiculata also secrete enzymes that break down proteins, releasing amino acids. The death and autolysis of the early-growing bacteria releases important "vitamins" for the late-growing Brett. When the glucose has run out Saccharomyces species begin to become dominant, as they can utilize some of the more complex sugars (maltose especially) that remain. Within 3-4 months the beer has now attenuated to the ~75% level of a normal beer. The unusual length of this stage is the result of the small inoculum, the lack of glucose to get the Saccharomyces started, and factors secreted by various early players that inhibit its growth.

The stage is now set for the real fun: Brett. and Pedio. These will have the most notable impact on the flavor of a lambic. Brett has not been seen yet in the fermentation because it is a slow grower and requires a lot of vitamins and amino acids. Now that autolysing organisms are offering up their bodies and they are given time to work, they will start to grow and produce their unusual flavors. Brett. derive their food from the starches mentioned earlier. They secrete an enzyme that breaks down starch and releases fermentable sugars. Brett. and other oxidative yeasts form a "pellicle" or crust on top of the fermenting beer, which protects the rest of it from oxygen. This important for Pedio. which will give a smooth, complex sourness to the beer, because it prefers an anaerobic environment. It is also important to prevent the growth of acetic acid-producing bacteria.

A Recipe:

This comes from Mike Sharp. It seems to make 28 gallons.

mashed in at 130F (160F strike water)
Raised temp to 158F
Started sparging with 180F water Collected ~35 gallons total in two containers
Started heating; added 2 cans M&F wheat to up gravity a bit
Started boil (yeah, takes a long time to heat this much!)
Added hops
Put on cover, removed from heat, cooled overnight in garage OG 12.7 degrees brix
siphoned to 10 & 15 gallon casks and a 3 gallon carboy
Pitched with the bugs listed above.

Drinking Lambics


Commercial Examples:

Don't mistake fruit beers for lambics. There are a lot of fruit beers that are not lambic (notable example: Sam Adams Cranberry Lambic). Lambics must be "spontaneously fermented," and should be from Payottenland. One set of beers that are easy to mistake for lambics is the excellent line from the Belgian brewer Leifmans (e.g. Goudenband). These are oud bruins and as such have sour and unusual yeast flavors, and some have fruit.
These lambics are by far the most easily found in the US. They are also the least traditional. They are pasteurized and sweetened at bottling, and the fruit versions seem to use some kind of fruit syrup as the flavors are strong and strange. They are reportedly blended with traditionally fermented beer to tone down the flavors that make a lambic a lambic.
Belle Vue, Mort Subite,Timmerman's:
Also fairly non-traditional makers, Timmermans has the patent on the banana lambic.
A highly respected lambic brewer. Their beers tend more to the acetic (vinegar) rather than lactic sourness. They make a beer they call Rose de Gambrinus which has raspberry, cherry, and vanilla flavors. Not distributed in California.
Another respected brewer, Frank Boon started off as a blender, buying other maker's worts and doing the fermenting and blending himself. Boon's beers are probably the most accessable of the quality lambics. Distributed by California Vineyards in California (415-595-1768).
Considered by many to blend the finest lambics, these are not imported to the US.
There are many other small makers and blenders but these are essentially never seen in the US.

Another Place to Buy Bugs

In addition to the suggestions in the Lambic FAQ, there is a nice company called Head Start Brewing Cultures. (615) 372-8511, ban5845@tntech.edu

Jeremy Bergsman