Diacetyl rest

[docpd]

I haven't done too many true lagers so my question is: in the opinion of the Borg, what is the optimal duration and temperature for the diacetyl rest? I didn't do it at all on my prior lagers but the fermenting temp on this one is a bit colder (45 degrees) so I think it would be advisable this time.

[swenocha]

I usually just do room temp for about 3 days. Why that temp and time? Dunno. Probably because EricG told me to do it. I probably should research that more fully, but it's worked well for my lagers so far (well, except for that first o-fest... it had some metallic off-flavors and wasn't pleasant)...

[mashani]

I've always done it as 3-4 days. Seems to be enough.

[BigPapaG]

It's interesting that it is called a Diacetyl Rest when in fact, it is the increased activity caused by warming the yeast that allows them to consume the diacetyl... It should be called a Diacetyl Reduction LOL!

I like to do mine after primary is done, usually by raising the temp about 10 degrees F, and hold it for three days. Room temp is ok too since primary is complete and the higher temp should not contribute to additional off flavors.

Some people advise waiting until overall fermentation is complete or just about complete but I prefer to do it a bit earlier... I think it gets the flavor out of the beer sooner which might be better... YMMV.

The rise in temp after primary also helps to drop a few gravity points usually...

Then, it's cooldown time for the lagering phase.

[FedoraDave]

I usually ferment at the recommended temp until the gravity is 75% done (in other words, if my OG is 1.060, then my projected FG is 1.015, so we're talking maybe 1.022 or so). Then I raise the temp by about 10 degrees for three days, and then lower it back down to what it was initially. Then bottle, keep it at room temp for 3 weeks, and then back into the fridge at fermentation temps for 3 or 4 weeks. And then I crash it in the mid-30s indefinitely. I've still got some Pearly Pils that I brewed on Labor Day and bottled at the end of Sept. It's been sitting in the fridge at 34 for a long time, and it's clear, crisp, and delicious.

Sure hope the judges agree with me.

[russki]

Once they get within a few points of projected FG, I usually give my lagers a week at 60-65F to ensure full attenuation. Then they go down to 32-34F for a couple weeks before bottling or kegging (not true lagering; more of an extended cold crash), then carb for 3 weeks at room temp if bottling, and back to almost freezing indefinitely.

[Crazy Climber]

I ferment lagers at 50 for 2 weeks, then raise the temp to 60 for two days for the D-rest.
Then, rack to secondary and lower back down by 4 degrees per day, until it's as low as I can get it (40-ish)...then leave it there for a few weeks.
YMMV.

[docpd]

Thanks for all the great responses.

[FedoraDave]

And, as usual, you asked ten homebrewers a question and got 17 answers.

You'll find the method that works best for you, Doc. All of these answers seem to be pretty similar; just individual tweaks to the basic outline, which is probably what you expected, given your experience. No doubt you get the idea, and you'll be tailoring it to the docpd brew house.

[packerduf]

I generally wait until I'm down to about two or three burps per minute in the airlock, then rack to a secondary for the diacetyl rest. I'd rather be a tad early to ensure a new blanket of CO2 forms over the beer. I raise the temp ten degrees for two or three days. Then I'll return it to my temp-controlled fridge and decrease the temp two degrees per day until I reach 33 degrees. Then I lager at that temp for about two months (depending on recipe/ABV). I don't bottle, just keg.

[Kealia]

Late to the party, but count me in the same boat as most here. Before fermentation is over I raise to about 65/68 for 3-5 days.

[Trollby]

Well I am really late to the party but between holiday's and on road for Search Warrants I have had very little time for my brew stuff.

I take a more Laid back approach:

16-21days 48-52*F
3days 60-62*F
Back to 48-52*F for a week or so then Bottle.

I like to maintain the 48-52*F for the life of the beer after bottling too