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Diacetyl Question

Does wort ferment vigorously during a diacetyl rest ? Making a pilsner, had vigorous fermentation in the primary at 52 degrees. As fermentation came to a visible standstill, I proceeded to raise the temp to the mid 60’s. But is no visible increase in fermentation of diacetyl. Is this normal?

A diacetyl rest should not produce any additional signs of fermentation. If any, they would be very mild.


You may have warmed ot prematurely. Better to let it ferment longer at the lower temp. May get some off flavor

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IIRC a diacetyl rest is performed when you’ve reached 2/3 of your anticipated FG… yeah pretty difficult to measure at the Homebrew level. So, with that said you can raise temps the second you see a lack in ‘fermentation’ or… you can do a ‘quick’ lager fermentation where you start at 50° and after about 4 days of ACTUAL fermentation start ramping the temps up by 1-2° per day. Your off flavors are created quickly into fermentation (around 3 days) so by warming it up your yeast will start cleaning up the byproducts.


That makes sense. I’ll generally ferment 49° for 2 weeks then do as you say incrementally raise to about 60° leave it a couple days then incrementally down to cold crash. Takes time but I guess its all part of the lagering process. @bpoppp doesn’t offer how long the beer was fermenting do we are just speculating until we get more information

I ferment at 50° for a week then start ramping the temps up 1-2° per day. That usually puts me at around 65° at the 2 week mark. I’ll let it sit for 3 days then crash it down to 35-36°. Depending on what I have going on I’ll let it sit to clear. Might be a few days, might be a couple weeks if I have time.

Primary for 7 or 8 days then zip. OG around 1.079 pitched 2 Lallemand Diamond dry yeast after rehydrating. Hit it with 60 seconds of O2. Fermented at 52 ish. Started to raise temp for d rest but dropped back down per replies to my questions. Will let it ferment for another week or two then try the d rest again, then crash it. I appreciate the input. Any more thoughts?

Have you taken any hydrometer readings? I don’t understand why you would need two more weeks of fermentation if you are at or near terminal gravity.

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