Brett Sour (3/9/14)

My latest sour beer uses the same quick-souring technique as my last two sours, sometimes known as sour-worting (a variation on sour-mashing). I mash the beer normally, but rather than boiling the wort after mashing, I cool it to 112˚F, add 1/4 lb of crushed 2-row barley, and maintain that temperature for 3-7 days. During this time, the native lactobacillus present on the barley produce lactic acid. The temperature inhibits the growth of spoilage bacteria and yeasts. After souring, I boil the beer normally, with a modicum of hops. The boil kills virtually all bacteria, so from this point onwards, the beer is no longer spontaneously fermented. I pitch a pure-culture strain of yeast and ferment according to that yeast's needs.

The only tricky part about this whole shuffle is keeping the beer at 112˚F for most of a week. I've gone through a few very kludgy solutions to this problem, including placing a keg in a (somewhat) temperature-controlled water bath. My current system is a bit more manageable, consisting of a lamp, a temperature controller, and an unpowered refrigerator. The temperature controller tells the lamp when to turn on and off, and the refrigerator provides insulation. It's basically an incubator. I can maintain my desired temperature (in this case, 112˚F) to within 2˚F for as long as I want.

For this particular sour, I decided to use Brettanomyces as the only alcoholic fermenter. Brettanomyces ("Brett") is an entirely different species from brewer's/baker's yeast. For most brewers and winemakers, it's a scourge to be eradicated, but it also produces characteristic and sought-after flavors in Belgian and American sour beers.

I used a strain of Brett (White Labs Brett Brux Trois) isolated from a bottle of Drie Fonteinen lambic. It has gained something of a following among some American brewers for use in 100% Brett beers. It is markedly less funky (barnyardy, smoky, spicy) than most strains of Brett. Instead, it produces tropical fruit aromas with just a hint of funk.

The grains in this beer (2-row, English medium crystal, flaked barley) would, with a normal ale yeast, produce a fairly typical American pale ale. However, the combination of lactic bacteria and Brett overwhelms the flavor of the malts. The hops are even less distinguishable.

Brewed 3/9/14.

3/16/14: Boiled with 0.3 oz of Columbus. Added Brett Trois. Fermented at 72F.

3/20/14: Medium-high acidity, fruity, slightly savory aroma. Low bitterness. Overall my best sour yet.

Kegged 4/6/14: More Brett aroma. Balanced and fruity.