i waded through the several hours of the brewing network's interview with chad yakobson (http://thebrewingnetwork.com/shows/866
) yesterday and jotted down some notes that i thought might be helpful to those of us out there interested in brett fermentations. these are my notes and, as such, they might not be totally correct. any mistakes are mine.
many thanks to chad for doing such excellent research on brett (and making fantastic beers at crooked stave--go to the tasting room if you get a chance. it's amazing). i would welcome any additions or corrections.
here's my summary:
-for some of his sours, he used a no boil sourworting, wherein he used acid malt to get the ph down to 4.5 for the mash (to limit other bacteria) and then pitched the lacto culture for a week. to kill the lacto, he heated to 185f for 15 min.
-all brett fermentation temps: knock out temp 68 f, then rise to 72-74. brett doesn't seem to respond to temp with esters the same way as sacc. aromatic compounds are a result of precursor chemicals found in the wort, which the brett converts (for example butryic acid becomes ethyl butrate--the pineapple aroma).
-similarly, brett doesn't respond to the sugars created by mash temps ranges in the same way as sacc. we all know that brett can eat long-chain sugars, but not more than it likes to eat short ones. to reduce the time in the fermenter, reduce the dextrinous sugars. mash low, no crystal. depend on the beta glucans in rye, wheat, oats for body. instead of residual sugars and glycerol produced by the sacc.
[side note: -brett doesn't produce glycerols, though this gets me thinking that selecting high glycerol yielding yeast such as saison strains would be a good move for mixed culture fermentation.]
-don't bottle brett beers until they hit 1.008 at least. they will continue to ferment and can result in overcarbonation. pressure seems to stimulate some added fermentation. bottled bretts are likely to ferment down to 1.004 or lower.
-for starters, use a standard 1.048 OG wort and let go for at least 7-8 days. his research documents that brett fermentation tends two happen in two bursts, an initial immediate and then another several days later. the different species and strains behave differently in this regard. brett b. trois/drei in particular is a slow but super-attenuative (more than others).
-if you want to store yeast, do it at room temp. bretts cultures that were been refrigerated were not viable over the long term.
-as for pitching rates, in the interview, i believe he suggested standard ale rates, though i've read him suggest on hbt 2x10^6 cells/ml per degree plato, which (in my understanding) is considerably higher.