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Author Topic: diacetyl rest  (Read 2693 times)

Offline bassriverbrewer

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diacetyl rest
« on: December 05, 2010, 11:35:17 am »
Whats the best time to do a diacetyl rest?  Is it when fermentation is winding down or after signs of fermentation has stopped?
I made a munich Dunkel with wlp 838 and after 10 days the krausen subsided and activity is very slow in the fermenter. There is still a thin layer of clean foam on the whole surface and the airlock bubbles every five seconds.  I'm planning on racking this into a secondary and putting in the fride to lager for three to four weeks

Offline chezteth

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Re: diacetyl rest
« Reply #1 on: December 05, 2010, 02:11:02 pm »
You want to do the diacetyl rest when the fermentation is winding down but not completely done.  I would do a diacetyl rest before transferring to the secondary fermenter.  Warm the fermenter to the mid to high 60's and keep at that temp for 2-3 days.  After the diacetyl rest is complete then transfer to secondary and lager.

Happy Brewing,

Offline tom

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Re: diacetyl rest
« Reply #2 on: December 05, 2010, 02:26:37 pm »
Technically when the fermentation is 2/3 done. Although all lager yeasts don't reqiure one.
(If your attenuation is going to be ~75%, then 2/3 of 75% = 50% , so when the gravity reaches 50% of the o.g.)
Brew on

Offline James Lorden

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Re: diacetyl rest
« Reply #3 on: December 05, 2010, 03:02:03 pm »
I shoot for about 1.5 degrees Plato above final gravity (6 gravity points).  You can calculate your expected final gravity by doing a fast ferment test.  Kai advocates this all the time, you can do search for the method.
James Lorden
Beer Drinker Beer Maker & Beer Judge