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
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,
Brandon
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.)
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.