People may wonder, "What's the point of brewing NA beer", but as in my case, health and other factors often come into play. Diabetics, recovering alcoholics, dieters, folks on medication, and plain old teetotalers can benefit from this information. If I may step briefly upon my soapbox, I'll propose that taking a break from alcohol without having to take a break from good beer is a worthwhile pursuit. One unexpected benefit from cutting (way) down on my beer drinking: my palate has drastically sensitized to many flavor subtleties I've obviously been missing in the past, and I certainly enjoy the occasional beer moreso as a result. I take my limitation as a challenge to find new means to beer appreciation. I think most of you would agree that homebrewing is not the pursuit of the ultimate *buzz* but rather the pursuit of the ultimate *beer*. But I know too that many of you ARE in it simply for the buzz; you may hit the Page-Down key at this point.
First, let me point out a great patent search engine at
http://patent.womplex.ibm.com/
It has over two million patents in its database, is fully seachable with simple or complex search strings, and you can even purchase a copy of the complete patent online for a nominal fee. You could also take the patent number to your local library which should have a complete copy and a copy machine. Anyhow, I used this search engine to search for patents relating to non- and low-alcohol brewing, in an effort to explore the range of methods that have been developed/disclosed for non- and low-alcohol brewing. The list of techniques presented here is in all likelihood neither complete nor comprehensive, but from what I have researched I'd say it covers a great percentage of the methods in use. Many "low-alcohol" techniques are easily adapted by the homebrewer; "no-alcohol" methods are typically much more difficult at "our" level.
I'll use the term "NA" to mean both non-alcoholic and low- or reduced-alcohol brewing or processing. Legally, alcohol content below 0.5% by volume is considered "non-alcoholic". Interestingly, I recently saw a report on the 'net by a university (Pittsburgh? can't remember) claiming that many fruit juices such as regular orange juice can contain close to 0.5% alcohol as a result of natural fermentation of the fruit sugars by wild yeast. It certainly *isn't* just for breakfast anymore...
1) Simply create a very low-gravity hopped wort and drink it without fermenting it. This techniques has appeared on the HBD in the past. Cara-pils seems to be a favorite base malt due to its high dextrin content and minimal sweetness; it can supposedly be primed and bottled since the cara-pils reportedly won't ferment (much). Gravities of around 1.010 to 1.020 are used, and roasted or crystal malts can be added to enhance character. This is truly "non-alcoholic" (but not if primed), but is it beer?
I tried this method a couple of times, with barely passable results. There are complex reactions that take place in a fermentation which contribute significantly to what we think of as beer character, and eliminating fermentation can result in only an approximation of "beer". However, it's easy and it's worth a try, and as I said, adding specialty grains can help greatly in producing a tasty beer-like drink. I found that acidifying the wort, either during or after the boil and chilling, to about 4.5 pH (close to a fermented beer's pH) helps drastically improve the flavor (though it adds a bit of tartness). Also, go easy on the hop levels. Hop bitterness is very harsh and grassy prior to fermentation (taste your next bitter wort for a convincing demonstration). I wonder if CO2 scrubbing of this wort might modify the hop character somewhat, and whether fining would help reduce hop phenols & tannins. Acidification definitely helps. Also, because of the low malt content, there probably isn't enough residual protein to give decent heading, though heading agents could perhaps be used to compensate.
Extract brewers can use this method, though the presence of fermentable sugars in extract leaves the risk of unwanted bacterial or wild yeast fermentation and/or spoilage.
Commercial examples of this method are sold in various places around the world as "malta", and Pappa Charlie has a recipe in his second book.
2) Produce a low-gravity wort and ferment it, resulting in a low-alcohol "real" beer. This has been covered several times in the various publications, most recently by Kirk Fleming in the April 1997 Brew Your Own ("BYO") magazine (an earlier BYO article on NA brewing is available on-line at The Brewery). I just kegged a low-alcohol porter that is remarkably good (considering!) and comes in at 2% ABV. Here are some thoughts on this method:
With a regular brew, you start a wort at, say 1.050 gravity and finish at, say, 1.015. When your beer is done fermenting, what do you have? The change in gravity is due to the conversion of sugars to alcohol, CO2, water, and other yeast by-products. If the entire contents of the wort were fermented into alcohol, the final gravity would be less than 1.000 due to the presence of alcohol (SG ~ 0.78). So the final gravity being greater than 1.000 indicates that other "stuff" is left over. This stuff is mostly unfermentable sugars ("dextrins") and proteins. These contribute to "body" and "mouthfeel", along with head formation and other characteristics.
If you can make a wort with little fermentable sugar but with the "normal" amount of residual "stuff", you should conceivably get pretty close to "real beer" without all the alcohol. One snag is that other yeast by-products, for example esters, are often desirable and would only be present in low amounts due to the minimized yeast acitivity. Also remember that alcohol itself is a significant part of the beer's flavor character, so a 100% perfect "fake" is perhaps not even possible. Is it really "beer" if there isn't any alcohol?
I mashed my porter with a single infusion at 160F (71C). At this temperature, beta-amylase (which produces simple fermentable sugars) is quickly denatured, leaving alpha amylase (which produces complex, unfermentable sugars) to attack the starch. I used "pale ale" malt as a base (and "normal" amounts of roasted and crystal malts); doing a single high-temp mash with regular "pale" malt (e.g., pils) might encourage serious protein haze unless a protein-degradation rest were done (see the last month's worth of HBD's for discussion of that topic).
Extract brewers can experiment with different brands of extract in order to find one which results in high final gravity; Laaglander is reputed to be such a beast. Ray Daniels' excellent book "Designing Great beers" has a table of various extract brands along with measured attenuation levels (page 15). This might be a good place to start your research.
Back to my porter. I ended up with a 1.030 OG and a 1.014 FG, for an apparent attenuation of 53% (compare to typical attenuations of 65% to 70%), and now I have a brew with satisfying fullness and flavor with less than half the alcohol as regular homebrew (and about 100 calories per 12 ounces). However, one other "stuff" thing that was noticibly weak was "maltiness". This should perhaps come as no surprise based on the reduced volume of base malt used (in order to achieve the low OG). Maltiness arises in large part from melanoidins, which can in turn arise from mash and kettle reactions (simple sugars + amino acids + heat) as well as the malting process itself. I used 2 lb munich malt and 3 lb pale ale malt, hoping that the realtively high melanoidin content of the munich malt would boost maltiness; it may have, but just not enough. Next time I'll try 100% munich, or I may even pressure-cook some of the first-runnings wort to enhance melanoidin production (a "pseudo-decoction"). The no-sparge brewing method might be of some help too (see HBD's from around Christmas). The use of 100% munich malt may require a protein rest in a pale beer; haze wouldn't necessarily be a problem in the porter although other benefits of a protein rest with this malt might be desirable. The trick is to avoid beta amylase activity as much as possible.
One final note on this method. I used Wyeast Irish Ale, noted for its low attenutation, to further discourage full fermentation. Dave Burley has recently noted deClerck's assertion that *all* yeast will 100% ferment all fermentables given the right conditions, so whether yeast selection is really a factor in controlling attenuation can perhaps be questioned.
3) Brew a normal-strength beer, monitor the gravity, and stop fermentation when a target amount of alcohol is produced. Some of the flavor benefits of fermentation are thus obtained. Fermentation can be halted (or at least drastically slowed) by filtering out the yeast (1 to 5 micron pore size). You almost have to keg this beer, since yeast must be present to bottle-condition, and this obviously would resume the fermentation ("glass grenade" time!). Chemical pasteurization is another possible alternative, though finding a suitable "yeasticide" is an issue. Heat pasteuration is possibly an option, and that provides a nice segue to another popular alcohol-reduction technique, which is to...
4) ...brew a normal-strength beer, then heat to evaporate the alcohol. Jack Schmidling wrote an article on this a while back (available on-line at The Brewery) and the method has been repeated in several other media. The idea is that since alcohol boils at about 175F (80C), and water boils at 212F (100C), the alcohol can be selectively removed while leaving the "rest" of the beer behind. The resulting product can be kegged or primed and bottled (add fresh yeast since you just killed the original colony!).
In HBD #1609, Maribeth Raines reports on her UV spectrophotometric assay analysis of alcohol content after applying this method to homebrew. The results she obtained indicated that in no case (including a half-hour of vigorous boiling!) did the alcohol reduce below 2% abv, calling into question the usefulness of this technique (though under controlled "lab" conditions she did have a brief success in achieving 0.5% abv -- please visit the HBD archive to see her full report). In addition, my own experience, as well as that of others having reported in the HBD in the past, is that other deleterious effects such as off-flavors, oxidation, and reduction of hop character can and do occur. If I'm only going to reduce to 2% abv, I'll stick with my low-gravity/160F mash schedule.
Why doesn't this method work well? Remember that water boils at 212F (at sea level), yet a pot of water at 212F will not just suddenly disappear -- it takes time. Same with alcohol -- it will take a long time to remove the majority of the alcohol. At the same time, evaporation of water will accelerate at 175F, so you lose water along with the alcohol. Over the period of time it takes to reduce the alcohol to very low levels, a lot of water will be lost as well. Certainly that can be made up with fresh water, but the point is that 15 minutes probably won't do it; according to Raines, it probably can't be done in the kitchen at all.
Another problem with this method is that it technically falls under the umbrella of "distillation", which is illegal, even though you're not collecting the evaporating alcohol (right?).
5) Brew a normal-strength beer, then freeze to separate the (frozen-ice) water & beer from the (still-liquid) alcohol. Again, The Brewery has an article detailing this approach. This method, like heating, is only partially successful at separating alcohol from beer, since much of the alcohol stays tied up with the ice in microbubbles and slush. Also, most of the "beer flavor" reportedly stays with the alcohol rather than the water. One solution is to heat the alcohol fraction and recombine the remaining "beer essence" with the leftover ice/water, but now you're back to the problems outlined above in #4.
This method is probably also illegal (deliberate concentration of alcohol).
6) Simple dilution of "normal" beer. You can probably imagine the results without even trying it...
One other interesting commercial method that seems to come up in several patents is often referred to as "cold-contact fermentation". Essentially, a wort is pitched with a huge concentration of yeast (40 million to as much as 135 million cells per ml) and holding it at near-freezing temperature. Apparently the yeast will metabolize some or all of the fermentables without producing much if any alcohol, or perhaps there's something else about the contact of this much yeast with the wort at low temperatures that gives the wort a desirable beer-like flavor or character. In any case, the wort is "cold-contacted" with the yeast as such for a brief 10 to 30 hours, then filtered, artificially carbonated, and packaged. Some patents refer to dilution to achieve 0.5% max abv, so it's hard to tell whether this method inherently *prevents* alcohol production or or simply reduces it.
Any of you yeast gurus have any information on what the biochemical details of the "cold contact fermentation" process are? Does this result in full fermentation without alcohol production? What's going on here?
I suppose the homebrewer could try this by racking wort from the kettle onto a full yeastcake (or three!) from a freshly-racked batch, fermenting for a spell (12-24 hours) in a refrigerator, then filtering and packaging (probably force-carbonating unless the beer is truly fermented out). If anyone has the equipment and inclination to try this, the information would be of great use to many of us. If the typical yeast cake is not an adequately high pitching rate for five gallons (for 100 million+ cells/ml), try it with only a gallon of wort.
Well, that about wraps up what I've found out about NA Brewing. As usual, comments are welcome, and any additions to this list would be worth posting too.