Brett Fermentation Temperature

Can't answer your specific questions, but East Coast Yeast recommends fermenting brett in the 60F - 74F range. Hope that helps a bit.

 

white labs specifies 70 to 85 for BBT.

 

I've just always done whatever the ambient temperature in my basement is (60 in dead of winter, 74'ish in summer). It saves space in my fermentation chamber for sacch. beers.

 

Everything will slow down the cooler it gets. I'm not sure about particular flavor effects of cooler temperatures but something to think about is that for many/most sour/brett beers they are aged in locations where the vessels are not kept at perfectly stable temperatures and the temperature swing over the course of a year is considered a useful part of the aging process. So I wouldn't worry about it. I'd probably rethink things if the beer always stays that cool but not if they stay around there for half the year or less.

 

I also put minimal effort into temp control IF I add brett post fermentation. If brett is the primary yeast, or is a component of my primary yeast I'll go with the best temp for the sach. yeast until primary is finished, then I keg the beer and stick it in the beer room in my garage for 6-9 months.

 

Chad Y from crooked stave has stated that he's found that his 100% Brett ferments aren't happy below 68.

Is your sour displaying a lack of sourness or lack of funk or both?

A friend of mine has some sours sitting in the low 60's. Some old, some young. In general i would say sourness and funk are gonna take very long to develop at those temps. Try your sour before this summer and then after.

 

Rodenbach controls at ~59F, but most breweries ferment/age their sours at least a few degrees warmer. Doubt that the flavors produced by the active microbes are appreciably different, but you may change the balance of which microbes are at work. Lower temperatures anecdotally reduce acetic acid production, but that shouldn't be an issue unless you are aging in a barrel anyway.