Importance of temp Control after Krausen has dropped?

[desabat]

How important is it to keep yeast in their recommended temp range once initial fermentation has completed? Can I for example take my Hefe out of the fridge after the first week to make room for a new beer and leave it at room temp (80s) until its finished without any off flavors?

I want to be able to brew every week but can only fit two fermenters plus conditioning bottles in my chest freezer so i have to either make room by moving fermenters out of the fridge once the krausen has settled at about a week or so or find recipes that ferment nicely at temps of 80-90s.

 

[SatanPrinceOfDarkness]

I've certainly read that temperature is less important once primary is finished. That said, heating it might activate. Moving it might activate. And 80s is pretty high. Also, if this is a good idea at all, it will depend on the yeast. A lager yeast is more likely to cause issues than an ale yeast.

If you do it, you want to keep the temperature change as slow as possible. Maybe a water bath would help. The water out of my tap is about 55F right now but ambient temperature is 70F. I was able to keep a wheat ale in the mid sixties by switching the water 2x a day (utility sink in basement).

Maybe transferring to secondary while it's still cold would help so there's less yeast to activate.

I've found it difficult to find perfectly clear instructions on post-primary fermentation/conditioning. It really does depend on the recipe and the yeast.

You could try siphoning off a gallon into a Carlo Rossi jug, letting that warm up (or stay cool), and compare them at the end. Post results

 

[m00ps]

Temp control isnt as important farther into fermentation. Its common to let most yeast warm up near the end to finish. But the 80s may be pushing it for most non-Belgian yeasts. I keep my thermostat at 68 to not have to worry about batches after they are out of the fridge

 

[gbing]

Ales such as heffs are a little more tolerant of higher temps, and that particular style is noted for its prominent esters, however, depending on how much lower the temp is in your chest freezer...you may see a decline in activity for a few days as the yeast conditions to the new ambient temperature.
80's are a little high, and you may find that the ester production may go overboard, an extended period in the fermenter should clear that up.
If you need to make the space in your freezer, you could always try a swamp cooler.
That's something I've never had to deal with, I live in a more northerly area, so even at the peak of summer, it's still cool enough in my unfinished basement to maintain ideal temps. And in the winter I just move my rig upstairs to a closet....
Hope that helps, let me know how it works out!

 

[peterj]

Yeah that's totally fine to take it out and warm it up after most of the fermentation is done. All of the off flavors and fusel alcohols will be produced in the lag phase and the initial vigorous part of fermentation. 1 week and a dropped krausen should be plenty of time.

If you're warming it up, you don't need to do it gradually, you can just move right out of the fridge. Obviously you wouldn't do this with a lager. And I wouldn't leave the beer in the 80s for too long because beers age faster at higher temps. Try to package a week or two after you take it out of the fridge.

I'm not sure what the other poster means by "activate" the yeast. The yeast should still be active at this point and they should stay active until they have fermented all of the sugar they possibly can and cleaned up byproducts of fermentation. So "activating" them is not a concern. The temp rise should actually help to achieve full attenuation and clean up.

And no reason to transfer to a secondary if you don't need one.

 

[k1ngl1ves]

Everything peterj said...

 

[SatanPrinceOfDarkness]

Yeah that's totally fine to take it out and warm it up after most of the fermentation is done. All of the off flavors and fusel alcohols will be produced in the lag phase and the initial vigorous part of fermentation. 1 week and a dropped krausen should be plenty of time.

If you're warming it up, you don't need to do it gradually, you can just move right out of the fridge. Obviously you wouldn't do this with a lager. And I wouldn't leave the beer in the 80s for too long because beers age faster at higher temps. Try to package a week or two after you take it out of the fridge.

I'm not sure what the other poster means by "activate" the yeast. The yeast should still be active at this point and they should stay active until they have fermented all of the sugar they possibly can and cleaned up byproducts of fermentation. So "activating" them is not a concern. The temp rise should actually help to achieve full attenuation and clean up.

And no reason to transfer to a secondary if you don't need one.

On activating the yeast - my understanding is that yeast begin to go dormant as they run out of easily accessible food sources. As mentioned here. My thinking is that doing anything to activate them increases the likelihood that they will come active and produce off flavors do to the stress of the high heat they would be in. Raising the temp and agitating a fermentor are both things we do to activate a stuck fermentation, so I see no reason why it couldn't wake up some sleepy yeasties.

Personally I think raising the temps of most beers to over 80F at any time is one of those things that is not a great idea, but might not really do much damage.

 

[peterj]

On activating the yeast - my understanding is that yeast begin to go dormant as they run out of easily accessible food sources. As mentioned here. My thinking is that doing anything to activate them increases the likelihood that they will come active and produce off flavors do to the stress of the high heat they would be in. Raising the temp and agitating a fermentor are both things we do to activate a stuck fermentation, so I see no reason why it couldn't wake up some sleepy yeasties.

Personally I think raising the temps of most beers to over 80F at any time is one of those things that is not a great idea, but might not really do much damage.

Maybe some of the yeast begin to go dormant, but a lot of yeast is still active at this point and for a while after fermentation has died down. We rely on the yeast that is left in suspension to get back to work as soon as we add more food (priming sugar) in order to bottle carbonate.

As long as your fermentation hasn't stalled, pretty much all of the available food sources will probably be depleted after a week in most beers. The yeast can't just be "reactivated" if there is no food source for them to be active on. And any amount of sugar that's left after this point is not going to be nearly enough to create any noticeable flavors even if the beer is sitting in the 80s.

This is also why you can warm your bottles up to whatever temperature to bottle carbonate. Because the small amount of priming sugar being fermented is not enough to allow the yeast to produce a noticeable amount of off flavors.

 

[Clonefan94]

My first homebrew was fermented too high, probably 75ish degrees or so. (before i knew about temp control, so didn't bother with taking exact temps, room was at 70,) I would have to look at my notes from years ago, but I believe it was US-05

Anyways, that beer was definitely full of hot of fermentation flavors, so I know exactly what that tastes like. Where I'll admit, I don't ever get a beer up to 80, I usually take most of my Ales off temp control about 5 days in, depending on airlock activity. They probably get up to the mid 70s at the most, but definitely above 70. I have never noticed any off flavors from doing this.

You'd probably be pretty amazed at the thermal mass of 5 gallons of wort and how long it actually takes it to get to room temperature by just being left out. I mean it doesn't take days to come up, but it definitely doesn't become 80 degrees in 10 minutes if it's been in the mid to low 60s. So even if you do have some active yeast still going, the main bulk of fermentation is probably past, and it's more of a gradual climb to that temp than you think. I'd have to think, after a week, the warmer temps might finish any leftover fermentation quicker, but I doubt it would do any harm.

My only caution on this though, would be to make sure and leave everything sealed up until you are ready to make your transfer. If you start popping the lid and exposing to oxygen, at 80 degrees, I think you could be ripe to start growing mold if you were opening the fermenter up at all.