Top-fermenting yeasts that many folks use at this scale, such as champagne yeasts, all have their favorite temperature. Higher temp generally yields more esters or fusel production, but this is not always bad. Lower temp will typically just take a long time, sometimes exponentially longer, and too low (<15C) may make your yeast dormant.
I try to keep all my washes fermenting at 25C, although for a straight sugar wash I've pushed it up to low 30's for a speedy ferment. Many yeasts won't handle above 30, and 40 is a typical "kill temp".
While it's preferable to keep a constant temp throughout the entire ferment, I've found if I keep 25-30C in the primary with lots of O2 to get the ferment started and "breed" the yeast, I can put it in the secondary and leave it at 16-20C with no worries. Ferment chugs along happily.Statistics: Posted by RoboStill — Tue Mar 05, 2013 8:10 pm
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