A Silk Purse from a Sow's Ear

or How to Make pLambics for Fun and Profit

Worts of Wisdom meeting March 29, 1995

Disclaimer:

Ingredients:

Grist:

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.

Hops:

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.

Water:

Use fairly soft water. The Hetch-hetchy water most people have around here is good.

Bugs:

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:

• Kloeckera apiculata
• Cantillon Pediococcus isolate
• Cantillon Brettanomyces isolate
• Pediococcus cerevisiae (ATCC 25248)
• Brettanomyces sp. (NRRL Y-1411)
• Brettanomyces sp. (NRRL Y-1412)
• Brettanomyces sp. (NRRL Y-1441)
• lactic acid generating bacilli #1 (untyped)
• lactic acid generating bacilli #2 (untyped)
• Saccharomyces globosus
• Pilsner Urquel 'D'
• Larkin (top fermenting ale yeast)
• Pasteur Champagne
• Lambic Girardin ala kilo (from keg of 6week old lambic)

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 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.

Fermentation:

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:

• lots-o deionized water
• 32lbs pale malt (domestic stuff, nothing fancy)
• 21lbs red wheat flakes
• 9grams gypsum (CaSO4)
• 9grams epsom (MgSO4)
• 1.25lbs old hops (various varieties)