Author Topic: Diacety Rest  (Read 4835 times)

Offline Beer Lover

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Diacety Rest
« on: June 20, 2015, 05:51:29 PM »
I have 2 lagers in primaries.  I will do a 48 hr Diacety Rest between the primary and secondary.  Do I leave the lager in the primary for the Diacety Rest or do I move it into the secondary for the Diacety Rest?

Thanks To All
Brews on Deck; Brown Ale and Pliny the Elder
Fermenting; Blonde Ale, Cream Ale and Smithwick Irish Red
In Bottles; Gave up bottling. Too much work.
Kegged; Bourbon County and Bourbon County Vanilla Rye

Offline twhitaker

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Re: Diacety Rest
« Reply #1 on: June 20, 2015, 08:06:36 PM »
Diactyl rests usually come after the secondary.
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Offline Scott Ickes

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Re: Diacety Rest
« Reply #2 on: June 20, 2015, 09:57:22 PM »
As quoted from John Palmer's book "How To Brew".

"Some brewers pitch their yeast when the wort is warmer and slowly lower the temperature of the whole fermenter gradually over the course of several days until they have reached the optimum temperature for their yeast strain. This method works, and works well, but tends to produce more diacetyl (a buttery-flavored ketone) than the previous method. As the temperature drops the yeast become less active and are less inclined to consume the diacetyl that they initially produced. The result is a buttery/butterscotch flavor in the lager, which is totally out of style. Some amount of diacetyl is considered good in other styles such as dark ales and stouts, but is considered a flaw in lagers. To remove any diacetyl that may be present after primary fermentation, a diacetyl rest may be used. This rest at the end of primary fermentation consists of raising the temperature of the beer to 55-60 °F for 24 - 48 hours before cooling it down for the lagering period. This makes the yeast more active and allows them to eat up the diacetyl before downshifting into lagering mode. Some yeast strains produce less diacetyl than others; a diacetyl rest is needed only if the pitching or fermentation conditions warrant it."

I would leave it in the primary for 48 hours, then rack it to secondary and lager it.
« Last Edit: June 20, 2015, 10:00:23 PM by Scott Ickes »
Kegs:
 Red IPA
 ESB
 Saison Solera
 Dubel (Aged in Malbec Wine Barrel
Aging:
 80 Shilling (In bourbon barrel)
Bottled
 Peppermint Patty Stout
 Wee Heavy

Scott Ickes
https://creativebrewing.wordpress.com

Offline Beer Lover

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Re: Diacetyl Rest
« Reply #3 on: June 21, 2015, 06:01:20 AM »
Thanks to Scott and twhitaker for replying. 
I agree Scott the diacetyl rest should be done in the primary.  That makes sense. 
I guess I should learn how to spell "diacetyl".
Brews on Deck; Brown Ale and Pliny the Elder
Fermenting; Blonde Ale, Cream Ale and Smithwick Irish Red
In Bottles; Gave up bottling. Too much work.
Kegged; Bourbon County and Bourbon County Vanilla Rye

Offline Scott Ickes

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Re: Diacety Rest
« Reply #4 on: June 21, 2015, 03:39:46 PM »
Based on everything that I've learned thus far, if you wait too long to perform your diacetyl rest, you actually miss your chance at it all together.
Kegs:
 Red IPA
 ESB
 Saison Solera
 Dubel (Aged in Malbec Wine Barrel
Aging:
 80 Shilling (In bourbon barrel)
Bottled
 Peppermint Patty Stout
 Wee Heavy

Scott Ickes
https://creativebrewing.wordpress.com

Offline jtoots

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Re: Diacety Rest
« Reply #5 on: June 22, 2015, 07:09:30 AM »
+1 for resting during primary.

Follow-up question in regards to the quote from Palmer.  The last lager I brewed, I chilled down about as far as I could go with my immersion chiller on a hot day (sub-70), then transferred to fermenter and pitched, then threw it in the chest freezer set for my goal fermentation temp (somewhere in the 50s I think? don't have my notes in front of me).  It took a few hours to get down as opposed to the "several days" Palmer mentions below.

Do you think this method risks diacetyl?  Better off pitching after getting down to temp with the chest freezer?


Offline Scott Ickes

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Re: Diacety Rest
« Reply #6 on: June 22, 2015, 09:18:09 PM »
+1 for resting during primary.

Follow-up question in regards to the quote from Palmer.  The last lager I brewed, I chilled down about as far as I could go with my immersion chiller on a hot day (sub-70), then transferred to fermenter and pitched, then threw it in the chest freezer set for my goal fermentation temp (somewhere in the 50s I think? don't have my notes in front of me).  It took a few hours to get down as opposed to the "several days" Palmer mentions below.

Do you think this method risks diacetyl?  Better off pitching after getting down to temp with the chest freezer?

My advice is to get it down to temperature and then pitch the yeast.  If you pitch the yeast at too warm of a temperature for a lager, then during the initial warmer fermentation temperatures, the yeast will produce more diacetyl and at the same time, they go through the primary much quicker.  Normally when fermenting a lager, you'll want to pitch at your fermentation temperature (let's say 50F), and then when your fermentation has dropped to about half of your original gravity, then you can start to slowly raise the temperature.  Let it slowly rise to say about 65F.  You should have enough sugars left for the yeast to have enough time to clean up any diacetyl that they originally created.  If you pitched to warm and had a lot of diacetyl, your yeast might run out of food and no longer be at their prime condition to effectively clean up all of the diacetyl.

This brings up the next question.

How will you know when your yeast have cleaned up all of the diacetyl?
The answer to this is actually quite simple.  Pull a small sample of beer from your fermenter and split it into two containers.  Refrigerate one sample and heat the other sample to 140F and hold it there for about an hour.  Cool the 140F sample down to the same temperature as the refrigerated sample then taste them both.  If they taste the same, then you've cleaned up all of the diacetyl and you can rack your beer out of your primary.  If you taste butter in the heated sample, then the yeast are still at work and need more time to finish the job.  Give it a few days more.
« Last Edit: June 22, 2015, 09:20:15 PM by Scott Ickes »
Kegs:
 Red IPA
 ESB
 Saison Solera
 Dubel (Aged in Malbec Wine Barrel
Aging:
 80 Shilling (In bourbon barrel)
Bottled
 Peppermint Patty Stout
 Wee Heavy

Scott Ickes
https://creativebrewing.wordpress.com

Offline jtoots

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Re: Diacety Rest
« Reply #7 on: June 23, 2015, 07:21:22 AM »
Great explanation Scott, thank you very much.

 

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