Originally Posted by Turner_Brown
I saw this on the Wyeast website:
Secondary Fermentation Temperatures:
• Ales: Same as primary fermentation (higher temperatures will increase diacetyl reduction rates)
So...If I take it out of the swamp cooler (wort temp <65) after primary and rack it to the secondary where temps will stay close to 72-75....
"Higher temperatures will INCREASE diacetyl REDUCTION rates" (this confuses me)
I am interpreting that statement in this way:
Higher temperatures will result in less diacetyl in the final product
Is this correct?
Yes, although it isn't necessary to do the entire primary fermentation at a higher temp just to deal with diacetyl. Those who worry about it (mostly those who lager) use whats called a diacetyl rest. What this involves is raising fermentation temps to, oh 65F+(depending on yeast) for a short time. Yeast will naturally clean up the diacetyl at the end of fermentation, the higher temps accelerate this action.
A for secondary temps, I'm a big fan of cold conditioning both ales and lagers. If you have fridge space, throw the batches in there once they're in secondary. On the whole, I don't think temps during secondary ale fermentations are nearly as important. You wouldn't ruin your beer leaving it in secondary at a 70-75+ teperature.