Diacetyl Rest temperature and duration

[user 225792]

My lagers (Munich Helles and Oktoberfest) are fully attenuated, racked and started into a diacetyl rest with temperature set at 67 degrees F (given a 2 degree swing). My temp sensors are attached to the side of carboy and insulated on the outside in order to get truer readings. Due to a few different factors, I could only get my fermentation chamber warm enough to get the beer up to 63 degrees F for a period of about 1.5 days. I have had the temp controller set at 67 for 5 days now, but only reached that 63 degree mark for 1.5 days in the middle of those 5 days. Question: is 63 degrees @ 1.5 days enough for a successful diacetyl rest?

I have a new heating source arriving today (carboy heaters). Should I extend the diacetyl rest period after bringing the beer temp up to around 65-67 degrees, or should I move on to ramp down for lagering temps?

 

[BucksIPA]

you would want to bring it up to 65 the last couple days as the yeast are still in the last phase of production. They would re consume the diacetyl. Bringing the temp up to the upper range of the yeast range will reduce the diacetyl the quickest, but getting up to 65 isnt required. Bring the yeast up to 63 for a day or 2 longer will result in the reduction of diacetyl as well. The colder it is the longer it takes to balance flavors. Holding around 60 for a week or 2 at the end of fermentation, then lagering for 60 days works just fine

 

[user 225792]

Perfect. Great intel! I received the carboy heating pads, and the temps came up nicely and are balanced around 65 now. I will let it go two days at that temp, then ramp down to 35. Thanks much!

 

[dmtaylor]

Diacetyl rest is optional. You might find you didn't need it anyway. Only way to know for sure is taste. Does it taste buttery? If not, you could skip the d rest.

Temperature doesn't matter that much. The difference between 61, 63, 65 F just isn't all that important. More important is the temperature rise, which is to keep the yeast eating.......

One more crucial point: Yeast eats diacetyl. But you racked and then initiated the d rest. You should have done the d rest before racking. For future reference.

 

[user 225792]

Some good advice there, Dave. Thank you. I did taste it beforehand, and there was a slight buttery taste. For the record, I actually racked some yeast into the clean carboy specifically for d-rest.