Author Topic: diacetyl rest  (Read 1448 times)

Offline DW

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diacetyl rest
« on: December 06, 2014, 05:01:59 PM »
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? 

Offline denny

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Re: diacetyl rest
« Reply #1 on: December 06, 2014, 05:29:52 PM »
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.
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Offline Wort-H.O.G.

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Re: diacetyl rest
« Reply #2 on: December 06, 2014, 07:55:43 PM »
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.
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Offline brewinhard

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Re: diacetyl rest
« Reply #3 on: December 07, 2014, 12:29:22 AM »
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). 

Offline hopfenundmalz

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Re: diacetyl rest
« Reply #4 on: December 07, 2014, 12:46:13 PM »
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.
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Offline ynotbrusum

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Re: diacetyl rest
« Reply #5 on: December 07, 2014, 12:53:42 PM »
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!
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Offline Wort-H.O.G.

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Re: diacetyl rest
« Reply #6 on: December 07, 2014, 01:06:37 PM »
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.


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Offline ynotbrusum

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Re: diacetyl rest
« Reply #7 on: December 07, 2014, 04:00:31 PM »
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.
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Offline HoosierBrew

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Re: diacetyl rest
« Reply #8 on: December 07, 2014, 04:06:28 PM »
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 !
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Offline ynotbrusum

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Re: diacetyl rest
« Reply #9 on: December 07, 2014, 04:11:18 PM »
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.
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Offline hopfenundmalz

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Re: diacetyl rest
« Reply #10 on: December 07, 2014, 04:17:24 PM »
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 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.
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Offline Wort-H.O.G.

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Re: diacetyl rest
« Reply #11 on: December 07, 2014, 04:25:49 PM »
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.

drink a redhook, and there you go.
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Offline erockrph

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Re: diacetyl rest
« Reply #12 on: December 07, 2014, 04:37:45 PM »
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.

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.
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Offline Stevie

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Re: diacetyl rest
« Reply #13 on: December 07, 2014, 04:44:14 PM »
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.

Offline morticaixavier

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Re: diacetyl rest
« Reply #14 on: December 07, 2014, 04:47:20 PM »
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.

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.
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