Primary Lager Fermentation Temperature Question

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Jan 19, 2009
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So im doing my first AG lager and after deciding to switch to a new yeast strain i had a question.
On the package it said fermentation temp should be 51-75F. But ideal is 51-59F. Right now i have it sitting at around 65F, and its been fermenting for about a day. Should i move it into a cold water bath, or should i just leave it. What difference will it make if i ferment at a colder temp, and what difference will it make if i leave it where it is?


Well-Known Member
Jun 6, 2007
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Well, disregarding what Fermentis says, lagers are best fermented cold (at or below 55°F). Most are good around 50°F, but some can go into the 40s without problems.

The ideal way to have done it would have been to pitch 2 packets (hydrated) at about 45°F and let it warm up to 50°F. But the question isn't what should you have done, it's what to do now.

I wouldn't pitch another packet. You're already fermenting and it won't do any good. I've heard lots of stories about "fruity" lagers when using many dry strains and fermenting them warm like yours is, so you might end up with a fruity lager. Most of these fruity esters are produced early in fermentation, so there may be no way to prevent it now. Plus if you crash it down to 50°F, you might shock the yeast and get a lower attenuation than you want.

I'd lower it by 5°F today, 5 tomorrow, and 5 the next day. That way you won't shock the yeast and you might reduce a little ester production. Then when it's about 3/4 done fermenting, warm it back up (you can warm up quickly) to the 60's for a couple days so the yeast can clean up diacetyl and other compounds. (A low yeast pitch rate and initially warm fermentation temps can also contribute to diacetyl production.) Then slowly lower to near lagering temps (5°F per day), rack to secondary, and lager.

If it's a medium-gravity to higher gravity lager (say, anything over 1.045), I'd lager it for like 6 weeks to try to clean it up a bit. In any case, it should still be a drinkable beer and may turn out better than predicted.


May 14, 2013
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Hey Guys...I have brewed many ale extract kits but attempting my first lager yikes! I have a temp controlled frig. With ales I can ice it down to 75 or so and pitch ale yeast which is also at that temp.

Have a World Wide Lager and liquid smack pack Wyeast. I do not know how to do a starter , I normally pitch my yeast right in the carboy. With this lager I could not cool down to 56 with ice so had to put in frig for night without yeast to let it get colder. This morning she is at 56. I activated my yeast last night (too soon I think) so I had to put swollen pack back in my regular frig. (colder).

Question is...where to go from here. Do I put the swollen yeast pack in the same frig as brew , let it also get to 56 same as brew , and then pitch.

Or let the yeast get room temp like I normally do, and pitch in 56 degree brew.

Any thoughts would be appreciated I have to do this morning.