Temp control - when / how to let fermenter warm up so yeast can finish

[N4teTheGreat]

Hi All,

If this is better off in the beginner forum, feel free to redirect. I'm still working on nailing my process and as such my previous attempt had a bit of banana, not really what you want from a stout.

I'm currently brewing an IPA and have had it sitting a cooler full of water and wrapped in a towel (along with ice, if needed) with a fan blowing on it during the day. Ambient in my apartment rarely drops below 70 and this time of year sometimes hits 73 - 75 but my swap cooler has kept the external thermometer on the fermentor around 65 for the most part.

It's been two weeks now and it appears that fermentation is more or less complete, so I'd like to let the fermentor warm up a bit to help the yeast wrap things up. Question is, how do I do that without things getting TOO warm given the ambient temp in my place. Should I just remove the towel and leave it sitting in room temp water or should I remove the fermentor from the water bath entirely? Thanks in advance for any and all advice, and yes I know I need to take a gravity reading soon to see where things are at.

Yeast Safale-05
OG 1.066

-- Nathan

 

[william_shakes_beer]

With a swamp cooler, precise temperature control that you are describing can be an issue. If you need to add heat, you can drop in an aquarium heater that will cycle around the temperature you set.

I think most people that raise temp towards the end of fermentation have a ferm chamber with mechanical heating and cooling. And, FYI, I have a ferm chamber with mechanical heating and cooling, and I always set my temp at the desired temp and let it ride for the entire ferment. But that's just me.

 

[balrog]

At two weeks, you're pretty much past the point in time where most folks would let the temp free rise. The bulk of the sugars are fermented within a few days to a week. Some folks measure, some just assume, and let the free temp rise start after 4-5 days. This is more important with lager yeasts of course, as those typically need a diacetyl rest, than with your SA05 ale yeast. Also, some English yeasts benefit from temp rise near the end to coax them into continuing fermenting rather than floccing out. But at this point you can just pull the fermentor to ambient temp as the temperature-critical portion of the yeast cycle (lag, growth & ferment bulk of sugars) has likely ended.

 

[Yooper]

My method is rustic, but all I do is stop putting frozen water bottles in the water bath in the cooler when I want to allow the temperature to use. I don't let it get as high as 75, but once fermentation slows down I stop actively keeping the temp as low.

What happens is that the temperature will go up a couple of degrees just as the fermentation is winding down and ending- exactly what I want. I do this at about day 5-7 or so.

 

[helibrewer]

Once the krausen has fallen, I reset my controller to 70 (from 66-68 depending). If it's a high gravity ale, I will go as high as 72-74 after high krausen.

 

[petrolSpice]

I let the bulk of the fermentation occur at 66F. Once the krausen is almost gone (just a thin layer left), I'll start raising the temp 1-2F per day until I get to 72F. I'll dry hop during this time if the recipe calls for it.

 

[seabass07]

Usually between 7-10 days into fermentation for me. After the krausen falls and it's pretty much to fg, I do a diacetyl rest. 2-4 days at 72f depending on the beer. Seems to be the sweet spot for my beer.

 

[Cellardwellerbrewer]

View attachment ImageUploadedByHome Brew1472749300.855783.jpg

I'm in the process of doing this for the first time. I'm on day 4 of fermentation. This morning it was at 66f, ambient around 80f.
I only put a 12oz ice bottle in this time. S-04 yeast, krausen starting to drop.
It's a oatmeal stout

 

[N4teTheGreat]

Thanks All,

I think nature may have unintentionally helped me out here as things did get a little warmer after the first 5 or 6 days, though I don't think the fermentor ever hit 70. I'll likely let it sit in the fermentor for another week to help things clear up (I also have no room to cold crash) take a few readings to confirm nothing got stuck and then bottle.