How Long Does Ferm Temp Matter

[Ridire]

Now that I have a fermentation chamber, is temperature crucial after krausen falls? I'm not talking about letting it get to 110 degrees or anything but can it just be left at a reasonable room temp after krausen without risk of off flavor?

 

[govner1]

I'm not sure if there is any specific data I can point to but as long as my wort is in primary I keep it at 64-68 for ales. I transfer to secondary once the krausen has completely fallen for dry hopping plus better clearing. Most often I maintain it at the same temp. Since I keg condition all my beers, once I've transferred to the keg I keep it at room temp 70/74 for at least two weeks before cold crashing in my kegerator.

 

[Yooper]

I've heard many times that fermentation temperature is important during active fermentation, but less so after fermentation slows or ends.

The thing is, I've heard it alot. But I've never once seen a study, data, empirical evidence, or an expert state that. It's more just common wisdom. That may be correct. But I've never seen it proven.

I keep my fermentation temperatures stable until the beer is packaged. That may not give you the answer you were looking for, but I know that's completely safe to do and gives me great results.

 

[davekippen]

I pull mine out after a week. After active fermentation the temp is much less critical. Like you said, dont let it get crazy, but mine goes from like a steady 64 (ferm chamber) to whatever room temp is, ~68 to ~75 probably for a couple of weeks. Then usually cold crash and keg after that. Or bottle, depending on the style.

 

[davekippen]

Mine is just another anecdotal example, Yooper! No science, but its worked for me. None of the noticeable off flavors from hot ferments with my process.

 

[Ridire]

Certainly the safest thing is to leave the temp control on until bottling day. I just ask because my chamber will only be big enough for one fermenter. I'm just wondering if is safe to pull one out of the chamber, after krausen has fallen, to put a freshly brewed batch in.

 

[RM-MN]

I think this article by Chris White of White labs has the answer you are looking for. In short, your off flavors develop early in the ferment, in the lag phase and the fast ferment phase. For these periods you need temperature control. Once the ferment slows, you can let your beer warm up without off flavors developing and it may even help your yeast get to the lower FG.

http://www.brewgeeks.com/the-life-cycle-of-yeast.html

 

[davekippen]

Thats a great article, thanks for sharing it!

 

[dmcman73]

I had the same exact question, glad I found this post! Mine had been in primary plastic bucket at a steady 65-68. After transferring it into my secondary glass carboy it had gone up to about 72 after a few days and I was getting nervous, I'm only two weeks in on fermentation (used liquid yeast).

Since it was brought up in this thread regarding waiting for the Krausen to fall before going into the secondary: Do you do it when it's starts to fall back or when it's completely gone, if that's possible. At one point during the first week of fermentation the krausen had reached up to my airlock in the 6.5 gallon bucket and when I opened it after 7 days to transfer to the secondary, it was at half of how high it had gotten. Is this good or should I've waited until it fell completely back into the brew? I did a hydrometer reading prior to transfer and it was coming along nicely and it had a really good taste to it.

 

[atreid]

Many people don't even secondary... So I'd let the krawsen completely fall off before I even think of secondary... IF you really want to.

For big beers or adding fruits, it's useful but these days I even throw the dry hops into the primary... Just let the yeast settle down a bit first if you go that way...

 

[jglazer]

I recently brewed a huge double IPA, the first week of fermentation was at ~64, then rose a few days to ~68, then I kegged and dry hopped it. I left the keg in room temps while dry hopping and the temp reached upwards of ~78 one day. I tasted it that day and I could taste a slight buttery taste that I did not taste before kegging. I then through it in the fridge, and tasted it once it was at lower temps (~40s) and it tasted amazing, no buttery off flavors.

Again there is not much data out there and I am sure some people have had problems with high tamps after initial fermentation has ended, but for me I've found that higher temps after initial fermentation can lead to some unintended flavors, but those slight flavor changes always disappear when the beer is cooled to serving temps. However, this was a double IPA and its totally possible the massive amounts of hops covered up any slight off flavors, but I couldn't tell.

Just one small example among millions of possible scenarios.