diacetyl rest

Not sure if my lager needs it or not.  It’s a bock that has fermented at 49-50 degrees, but if I taste that buttery diacetyl flavor I was gonna do a rest.  How and when do you do it?  Towards the end of fermentation, let the temp raise 10-15 degrees for several days?  Do you do when fermentation is complete or as it slows down?

I wait until fermentation seems complete, the pull a gravity sample.  If I taste d, I do a rest before racking the beer so there’s plenty of yeast left to clean up the diacetyl.

yep take gravity reading and if you’re about 55-60% attenuation, start ramping temp up. for me this is about 5 days at 48-50F, then let it rise to 65F and hold about 48 hours. when gravity is stable, start dropping 3-5F every 12 hours until 30-32F. some people will just skip the incremental temp reduction and cold crash- i’ve done this as well.

I like to start raising the temps slowly just as the krausen starts dropping back into the beer.  That lets me know that the fermentation is slowing down and the yeast could probably benefit from a few degrees temp increase.  I always do a diacetyl rest regardless if I need one or not (I don’t check to see if I need one first).  I figure either way warming up the beer and yeast towards the end of fermentation does not harm and can actually do some good (i.e. speed up diacetyl intake and increase attenuation).

The increased yeast activity in the D-rest also will scrub out sulfur, which is something of a benefit.

I never seemed to need the D-rest but have been doing it lately thinking that maybe my palate is not sensitive enough to pick up the flavor… But I I like buttered popcorn, so go figure!

As mentioned, the rest is more than just scrubbing diacetyl. All yeast I’m aware of produce a level of diacetyl. The amount produced and the amount detectable by an individual varies. Basically I see the rest as an accelerated lagering process when started at 5-6 days . Even if I didn’t taste or smell any diacetyl, the process of ramping temps up and resting allows the yeast to finish sooner and clean up- that can happen with lower temp and longer lagering schedules. I’m just one of the individuals who can detect very low levels of diacetyl, and so this schedule for lagers works for me.

Just curious - how do you perceive it to be?  I have heard from others that it is buttery tasting, or slick in the mouthfeel or even perceived as a bit of soap in the nose…is there a commercial example where it is prevalent to be able to know what I should be tasting or feeling?  I honestly think that I may be “blind” to it and wonder if there is a way to overcome the blind spot.  I am starting a BJCP class next week so I hope that I can make it through the various faults with enough sense to actually evaluate the beers to be judged.

I get the movie theater popcorn butter thing and the slick mouthfeel. I’m pretty sensitive to it, maybe not as much as some. If you lived closer to Indy I could take you to a brewpub that puts out a D-bomb on occasion !

I am sure that we will cover it in the class, so I guess I will have to wait for that session…IIRC some English ales are Diacetyl touched intentionally.  I will look into that.

I can taste diacetyl in most Sam Smiths beers. When judging I rely on the slick mouthfeel.

Some people are blind to it, I have a high threshold compared to many in the club. If you are blind to it, beyond the slick feel, not much you can do as it is like being color blind.

For some of my beers, I ask Mrs. R to taste for diacetyl as she is more sensitive to it.

drink a redhook, and there you go.

+1 - If you really want to taste it, it stands out the most in their pilsner. At least it did years ago when I had about 3 or 4 sips before dumping out the rest.

I can’t recall ever getting diacetyl from a red hook beer. Maybe it is an issue with their New Hampshire brewery. Do you get it from Widmer as well? I have tasted it in a kona beer once or twice.

go tot he store and get a bottle of imitation butter flavor in the spice aisle. this is diacetyl. you can then dose your beer of choice with tiny amounts and train your brain.

That’s a good idea.

red hook pilsner- loaded. haven’t had it in 2 years but cant imagine its changed.

In nyc and having a carlsberg Pilsner- diacetyl bomb if you want to know what it tastes like. My wife takes a sip and say"I don’t like it tastes buttery" and she knows nothing about diacetyl.

Edit: yep sent it back and got an allagash white… Much better.

For a Diacetyl you want to raise your temp just as your yeast growth starts to drop and when you are close to about 60% of your attenuation.

I’m one of those “lucky(?)” people who can perceive diacetyl in minute amounts.  While it does help with judging, it makes enjoying some beers sort of difficult!

When it’s in small amounts, it’s more of a “slick” or oily mouthfeel.  There really isn’t much of a taste there, but instead more of a texture if that makes sense.  In greater amounts, it has a bit of butter taste and in large amounts, it screams BUTTERSCOTCH at you.

Since some people simply can’t taste diacetyl, there are some funny looks sometimes when I say, “Ugggh, diacetyl!” and a friend of mine thinks I’m crazy!