How and when do I do a diacityl rest

[LarryC]

I have a Stone Levitation clone fermenting now and according the the Can You Brew It podcast I should do a diacityl rest. I've poked around a bit on this topic but can't find the definitive answer. How and when do you do it?

Thanks!

 

[Brew-Jay]

I am curious to year what others post. I do it by letting the beer sit for a few days near the top of the yeast's recommended temp after it is done with vigorous fermentation. That just allows the yeast still in solution to clean up behind their brothers and sisters.

 

[Brewskii]

As you probably know, the idea is to let the yeast get active towards the end of the fermentation to reduce/metabolize any off products made in the early stages of the growth phase.
My belief is the yeast will do this at the upper reaches of their recommended temp range or a little higher as the simple carbs are depleted.

Usually 4 days at low range temp, then free rise to ambient.

 

[LarryC]

So this brew was done with White Labs WLP007 at 67°. It's bee three days of vigorous fermentation but it has now slowed to a bubble every minute or so. I have bumped up the temp to 69° and the White Labs site says 65° to 70° so I guess I'm towards the top end.

Normally I would just leave it at that temp for the rest of my fermentation time (usually 2 weeks but sometimes 3). I have a fermentation chamber so maintaining the temperature isn't an issue. Should I hold it at 69° or ???

By the way, I'll be dropping in some hops over the weekend for an Amarillo dry hop. Does that matter much (temperature wise)?

 

[Brewskii]

So this brew was done with White Labs WLP007 at 67°. It's bee three days of vigorous fermentation but it has now slowed to a bubble every minute or so. I have bumped up the temp to 69° and the White Labs site says 65° to 70° so I guess I'm towards the top end.

Normally I would just leave it at that temp for the rest of my fermentation time (usually 2 weeks but sometimes 3). I have a fermentation chamber so maintaining the temperature isn't an issue. Should I hold it at 69° or ???

By the way, I'll be dropping in some hops over the weekend for an Amarillo dry hop. Does that matter much (temperature wise)?

My opinion;

D rest is about metabolizing. After you reach FG -like in 10 days or so -keeping the brew that warm is going to keep aging from really happening. Aging is more of a physical maturation by settling. For that you need cooler temps.

If you have temp control I would push your temps out a bit. D-rest at the max or higher and ferment on the cold side of the range. After the first few days of fermenting you are a very little risk of producing esters.

After d rest and you reach FG. Cold crash it. Like 65F.

 

[BigFloyd]

So this brew was done with White Labs WLP007 at 67°. It's bee three days of vigorous fermentation but it has now slowed to a bubble every minute or so. I have bumped up the temp to 69° and the White Labs site says 65° to 70° so I guess I'm towards the top end.

Normally I would just leave it at that temp for the rest of my fermentation time (usually 2 weeks but sometimes 3). I have a fermentation chamber so maintaining the temperature isn't an issue. Should I hold it at 69° or ???

By the way, I'll be dropping in some hops over the weekend for an Amarillo dry hop. Does that matter much (temperature wise)?

You're fine with a "d-rest" in the 69-70*F range while it finishes up. I typically step-up all of my ferments anyway, even the ones using yeasts that aren't known to be big diacetyl producers. Unless I'm specifically looking for some fruity ester character, I pitch a few degrees lower than the low end of optimal, ferment a the low end of optimal for 3-5 days then let it slowly come up over the next week or so to finish near the high end of optimal. I like the results.

You're good with dry hopping at the current temp. Amarillo.......yum.

 

[02fx4dude]

I've only done about 10 batches of lagers. My understanding from my reading here is the d-rest should be done when the beer is most of the way fermented but has not completed. I usually can tell when fermentation slows and check gravity. When gravity is around 1.018 I raise the temp to upper 60's for the d-rest.

Here's a site someone else pointed me to, check the section on maturation of the beer. It covers a few different schedules, hopefully doesn't leave you more confused.

http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers#Maturation_of_the_beer

 

[LarryC]

Thanks for the replies all, I guess I'm on the right path. I did have one hiccup with this brew - the controller on my fermentation chamber shut off during the beginning of the fermentation and the temp got up to 70°. I'm not sure how long it was there, maybe a few hours before I noticed. Then I brought it back down to 67° over 5 or 6 hours. Hopefully the yeasties will clean all the byproducts up and it will be one tasty ale.

 

[MindenMan]

I always use ESB 1968 for my yeast. In higher temperatures in the 72 F+ range, this yeast really needs a d-rest. In some beers a little fruit is welcome, but never butter. I ferment at 62-64 for 5 or 6 days, depending on how busy the airlock is and what the current gravity is. I will then raise the temperature by 1 degree a day until I hit 70, and leave it until I have time to bottle. My beer is much cleaner tasting as well as being very clear too.