How critical is temp control AFTER active fermentation is over?

[TANSTAAFB]

I didn't read all responses - not enough time - but one thing you didn't mention in your post is raising the temperature at the end for the purposes of increasing attenuation. I apologize if this has already been discussed, as it's not exactly ground-breaking stuff, but it's such a damn useful (and in my opinion, important) technique that I figured I'd mention it anyways, just in case.

When I'm going for a really dry beer, I'll try to knock another few gravity points off by increasing the temp by 1-2°F per day, sometimes up to the low-mid 80's - and in rare and extreme cases, the high 80's and even low 90's! At this point, the yeast is really doing such a marginal amount of work that any off-flavors potentially produced will be absolutely negligible (most of the time, if timed right), and yet that added bit of dryness will noticeably enhance the character of the beer. Seems like a no-brainer to me if you're working with a style that benefits from high attenuation.

Then I'll often cold-condition it. And although I'm fairly sure it should at least have some small effects on flavor in addition to (and largely because of) the yeast dropping to the bottom and clearing the beer up, I'm not nearly as confident that it will have a noticeably positive effect as I am about raising temps to further dry out a beer. So I wouldn't mind seeing your conclusions.

I do this all the time with my Belgians. My dubbel showed signs of active fermentation for 14 days with a good pitch of 550 as I kept bumping the temps when it showed signs of slowing down! I always raise temps a little at the end of fermentation to allow the yeast to clean up, but it is still in a controlled environment.
I am talking about taking a beer that is 1-2 weeks under temp control and moving it into a room where the temps can swing considerably over the course of the day and even more over the course of 2-4 more weeks on the cake. I also bottle condition at room temp (in the same room I will be moving my fermenters to) and they carb quickly and come out clean...not concerned with moderate temperature fluctuation during bottle conditioning but during bulk conditioning.

 

[emjay]

I do this all the time with my Belgians. My dubbel showed signs of active fermentation for 14 days with a good pitch of 550 as I kept bumping the temps when it showed signs of slowing down! I always raise temps a little at the end of fermentation to allow the yeast to clean up, but it is still in a controlled environment.
I am talking about taking a beer that is 1-2 weeks under temp control and moving it into a room where the temps can swing considerably over the course of the day and even more over the course of 2-4 more weeks on the cake. I also bottle condition at room temp (in the same room I will be moving my fermenters to) and they carb quickly and come out clean...not concerned with moderate temperature fluctuation during bottle conditioning but during bulk conditioning.

Ah okay.

Well on the high end of temperature fluctuations, you can expect further attenuation and negligible off-flavors for the exact same reasons stated above. The yeast doesn't care if the temps were raised intentionally or not, and once you've reached the point where you would normally start raising temps, thermal shock is really no longer a concern at all in a typical homebrewer setup. If the temperature fluctuations are merely caused by uncontrolled ambient temp swings, then as long as you don't put it somewhere with extreme temperature changes like outdoors, or an un-insulated shed, the thermal mass of the beer in the fermentor will allow it to respond slowly enough to protect the yeast. The only exception to this for the vast majority of homebrewers is when the sudden drop in yeast activity near the end of active fermentation causes the expected drop in beer temps (and in particular, yeast core temps) and adding ambient drops in temperature to the already-quickly-cooling fermentor can shock/stun the yeast and make it go dormant simply as a result of how quickly the temp dropped - which can still happen even if the temperature it quickly dropped to is considered optimal for the strain.

But I'm pretty sure we're talking about a slightly later stage in the process of making beer. However, the implications of temperatures quickly dropping remain the same; the only difference is that the yeast are generally past the point of causing their own temperature drop. This means it's strictly ambient temperature that would need to be able to drop the temperature of the entire thermal mass of a fermentor, and as I mentioned, it's a fairly slow process - almost too slow to matter, unless you're leaving your fermenter outside (or somewhere with a similar temperature differential) in the middle of fairly cool weather. But few people would put their fermentor outside UNLESS they're using it as a form of temp control. Most people know it can be a bit extreme for simple storage, and if they stick a fermentor outside, there is almost always an extremely deliberate reason for doing so.

Regardless though, as I'm sure most people here know, uncontrolled cooling can sometimes result in unintentionally or prematurely causing the yeast to fall out of suspension.

So to answer the question posed in the title of the thread: it's really not that critical at all. Stunning the yeast by means of fluctuating temperature drops through strictly ambient means is extremely unlikely (unless it's consistently cold enough that eventually the beer will just cool to outside the yeast's functioning range... but that is easily anticipated and easy to avoid). The most you have to consider is whether you want to dry out your beer further, because if you don't want to, you should stick it in a fairly cool room, knowing that fluctuating to temps warmer than the primary fermentation temp will encourage the yeast to attenuate further, and that the uncontrolled coolness of the room is unlikely to stun the yeast unless you take further, intentional measures (lagering, cold-conditioning, etc). And if it IS a beer you intend to dry out first, then you don't even have THAT consideration to make!

 

[Sithdad]

I think what you are looking for can be found on pg 97 of the Yeast book. Here they talk about temperature control during fermentation. They say that most of the flavor profile is created during the first 72 hours of fermentation and that's when temperature control is most critical. They warn that rapid temperature swings and cause the yeast to release heat/cold stress proteins, which prevent the yeast from excreting flavor proteins. They go on to say that cold crashing the beer before the yeast have had a chance to finish up can cause the yeast to not fully attenuate and for off-flavor compounds not to be cleaned up.

They do suggest doing a something similar to a diacetyl rest, even for ales. After fermentation has completed allow the beer to warm up (4-10°F) will allow the yeast to speed up their metabolism and fully attenuate and to clean up, without the fear of stressing them and causing them to produce off-flavors.

After you've raised the temp and allowed the yeast to clean up you'd have to treat your fermentor like bottled beer. If you don't bottle it once it's finished you need to keep it cool to slow down the aging process.

 

[Hokie_Brewer]

subscribed.

I asked this same question a few weeks ago, and never got a definitive response. Interested to see your results

 

[winvarin]

After you've raised the temp and allowed the yeast to clean up you'd have to treat your fermentor like bottled beer. If you don't bottle it once it's finished you need to keep it cool to slow down the aging process.

Even bottled, I would be careful about getting the beer excessively hot (although I am not convinced upper 70s or even low 80s really qualifies as too hot).

In addition to the BBR episode mentioned earlier in this thread, there is an article in the march/april 2011 BYO outlining a storage condition experiment. Nothing is ever definitive in my book, and I tend to like my beers better that have been stored at room temp than those stored in the fridge. But the experiment seems to indicate that extended storage at high temperatures (garages and attics in the study) will have adverse effects on flavor and aroma.

That being said, I have a single carboy fermenting fridge myself. I routinely move beer that has finished active fermentation to an upstairs bathroom in order to make space for my next batch in the fridge. The upstairs room adjoins an attic and as such, is subject to wide temp swings (lower to upper 70s).

I've never done a side by side with the same beer, but I have not noticed any differences in flavor between beers that rode out the entire 3+ week primary in the fermenting fridge vs. those that were moved out of the fridge after a week to make room for another beer.

Good on you for doing the experiment. Let us know how it turns out. It might have me changing my process as well.

 

[jfowler1]

In addition to the BBR episode mentioned earlier in this thread, there is an article in the march/april 2011 BYO outlining a storage condition experiment. Nothing is ever definitive in my book, and I tend to like my beers better that have been stored at room temp than those stored in the fridge. But the experiment seems to indicate that extended storage at high temperatures (garages and attics in the study) will have adverse effects on flavor and aroma.

Thanks for confirming that. They are actually the same experiement done by the same two people. It was a BYO/BBR collaberative. One is audio, one was in print.

....just in case anyone was interested in reading/listening for themselves.

Joe

 

[EoinMag]

I've had a bottle conditioned ale go clovey on me after standing it next to a radiator in winter. The beer had no trace of phenol on bottling and would have had 3-4 weeks in the fermenter so was definitely through the primary.

 

[TANSTAAFB]

First off I want to reiterate that I am in Texas where it is already getting hotter than it should in a place widely considered to be habitable by humans and beer

Not worried about the cold Ontario, worried about the hot. I read the part in Yeast that discussed the yeast releasing flavor compounds and THAT is exactly what I'm concerned about.

The BYO/BBR experiment was on the effects of extended storage of bottles...they ended up oxidized when left at extremely high temps for too long. I want to know how moderate temperature swings will affect bulk conditioning beer. It is climbing into the 90's here and quickly headed for the hundreds. I really don't want to spend the money to AC the room where I have all my brewing stuff. I bottle condition my beer in there and it carbs in 3-7 days! Built in warm cellar but want to make sure that doesn't affect a perfectly good brew that is conditioning and clearing.

 

[chezhed]

First off I want to reiterate that I am in Texas where it is already getting hotter than it should in a place widely considered to be habitable by humans and beer

Not worried about the cold Ontario, worried about the hot. I read the part in Yeast that discussed the yeast releasing flavor compounds and THAT is exactly what I'm concerned about..

I am not far from you and also greatly interested in your experiment. To be honest, I'm not real considerate of temps other than the first couple days. I have one fermentation chamber and nothing ever sits in there for more than a week....regardless. After that it moves to the least variant temp room in the house,which can swing right now from 69 to 73 with the doors and windows open...it's been in the low 90 already but then 56 at night. That will end soon when the house AC gets kicked on. (House is very shaded and room is completely internal, stone tile on slab so it is nice for beer to me.)

So far, no real notice to me...I force keg and keep them ambient as well in the house when summer comes, otherwise they are in the garage. I notice some taste variation I think but with 5-6 different beers in between each batch, I'm not sure I can really say....nor do I think I really care

 

[tesilential]

I only have one chest freezer which I use for fermentation, but I want to get into kegging as well. Can I keg and store them at room temp (76-78) for a couple weeks while they condition, then turn the freezer down to 40 to carb and condition? I would purge the air from the kegs and top off with co2, of course.

 

[Old_E]

I only have one chest freezer which I use for fermentation, but I want to get into kegging as well. Can I keg and store them at room temp (76-78) for a couple weeks while they condition, then turn the freezer down to 40 to carb and condition? I would purge the air from the kegs and top off with co2, of course.

This is what I do. I have a kegerator, and I don't see a fermentation chamber in my near future. I keep the bucket cool with the ol' Igloo cube/water/ice bottle method. Then after active fermentation is over, I just pull it out and keep it at room temp. I haven't noticed any off flavors since doing this, and have been very happy with my beers. I just leave them at room temp until I kick a keg and its time to refill.

Although today is nice... its definitely getting hotter here in T-town.

 

[TheSlash]

Nice thread!

So I have the Bee Cave Haus Ale fermenting with nottingham in a 59-60 degree basement cabinet. Is it OK to keep it at this temp for a couple weeks then cold crash and keg? Or do I really need to raise it up to 70 for a few days before cold crashing?

I suppose I could get a brew belt and try that, just nervous about it going over 70..

 

[erikpete18]

Nice thread!

So I have the Bee Cave Haus Ale fermenting with nottingham in a 59-60 degree basement cabinet. Is it OK to keep it at this temp for a couple weeks then cold crash and keg? Or do I really need to raise it up to 70 for a few days before cold crashing?

I suppose I could get a brew belt and try that, just nervous about it going over 70..

Haven't used Nottingham, but as long as its fermented fully out it should be fine without the warm up, and I'm pretty sure Nottingham is pretty good at lower temps. The only reason I could see raising it up into the 70s was if you thought it had produced a bunch of diacetyl that you wanted to try to clean up. Unless you can taste it in your hydrometer samples, I wouldn't worry too much about the diacetyl, but maybe someone with a little more experience with Notty will chime in.

 

[bmantzey]

Okay, I didn't read the entire thread but I wanted to give my 2¢. The way I see it, fermentation is not over until you drink it. When you put it in the bottle, the yeast needs to be healthy enough to continue processing the priming sugar in order to produce the natural carbonation.

Scientifically speaking, I'm not sure 80 degrees would cause too much harm to the beer, but I do know that you can affect the flavor of the beer even after it's been bottled if you don't hold the temperature constant.

Another thing I would look into is lagering. I haven't personally learned exactly how to do it, but I know that with lagers, some people take their brew out of the primary and put it into a secondary when primary fermentation is complete and let it sit for quite some time at a low temperature (33°, I believe). Now, if primary fermentation is already complete, what's the point of this if there wasn't some very significant effect?

Sorry it's not factual or scientific but hopefully it gets you thinking and maybe sets you on the right path to the answer you seek (if you haven't already found it). Cheers!

 

[TANSTAAFB]

I think what you are looking for can be found on pg 97 of the Yeast book. Here they talk about temperature control during fermentation. They say that most of the flavor profile is created during the first 72 hours of fermentation and that's when temperature control is most critical. They warn that rapid temperature swings and cause the yeast to release heat/cold stress proteins, which prevent the yeast from excreting flavor proteins. They go on to say that cold crashing the beer before the yeast have had a chance to finish up can cause the yeast to not fully attenuate and for off-flavor compounds not to be cleaned up.

They do suggest doing a something similar to a diacetyl rest, even for ales. After fermentation has completed allow the beer to warm up (4-10°F) will allow the yeast to speed up their metabolism and fully attenuate and to clean up, without the fear of stressing them and causing them to produce off-flavors.

After you've raised the temp and allowed the yeast to clean up you'd have to treat your fermentor like bottled beer. If you don't bottle it once it's finished you need to keep it cool to slow down the aging process.

Nice work finding this!!! I just re-read that section and it looks like the increase in temp towards the end of active fermentation may actually help this beer rather than hurt it. The suggestion to raise temps by as much as 10*F to clean up and fully attenuate is right in line with this experiment. I usually conduct a diacetyl rest but I guess I missed that part about just how much of an increase can be used w/ little to no effect on flavor...its possible that the one at room temp may actually be the better brew!

This section also discussed the fact that yeast will release heat shock proteins when under any stress, not just heat, so temp control is still important, just not as critical. Looks like extreme swings would be detrimental, but that isn't really a surprise now is it?

 

[TANSTAAFB]

I brewed my Tasmanian Diva Dry Stout today and needed the room in the ferm fridge, so I pulled the carboy of Saccharomyces' Belgian Pale Ale out, replaced the blowoff with an airlock, and set it in my office/ brew room. It has only been five days since brewing and there is still a little airlock activity, so I will keep the room cooled to the low 70's through the weekend, but then the A/C gets turned off and this brew is at the mercy of the Texas sun and any temperature swings it generates.

On a seperate note I managed to get over 90% efficiency on my stout today :rockin:

 

[TANSTAAFB]

Well, the Texas sun put the kibosh on this little experiment...to an extent. Apparently summer is coming early to Texas, as we hit 100...in April...2 days after I turned off the A/C in the beer room to conduct this split batch experiment

The thermometer in that bedroom read a LOW of 85* this morning and it was only going to get hotter from there. Sooooo, I moved the carboy into the master bedroom closet where it stays 75*F or lower all day. I really wanted to see what 80's or even low 90's would do, but I have no interest in ruining 4.5 gal of beer for the sake of science, even beer science

The beer temp in the carboy never got higher than 78* or 80* according to the fermometer and is still bubbling a little while the temp controlled beer stopped showing visible signs days ago and has never gotten higher than 70*. The difference in attenuation (if any) will be equally interesting to me. Do the yeastie beasties keep working slowly and quietly under temp control or do they stop eating sugar and just reabsorb diacetyl, acetaldehyde, and such?

I will be bottling on Sunday May 1st and will update again then

 

[63belair]

Just stumbled across this thread and read the whole thing, any updates? I'm particularly interested because I just brewed my first batch since moving down to Maryland from New England area and am wondering what the warmer weather will do (no climate control in the apt).

Fermometer was reading 73 when I pitched on Saturday and has been at ~79 since Sunday morning with visible consistent airlock activity. I put a fan blowing on the bucket and am probably going to move it into a tub w/some ice water when I get home from work today if the temp is still at 79.

 

[Jboggeye]

63, what yeast are you using and what are you brewing?

 

[63belair]

Safale WB-06

6lbs wheat malt syrup
1oz tettnang (60 min)
1lb honey (0 min)

 

[Jboggeye]

cool, a dry wheat yeast... most of your flavors will have developed at this point, but it won't hurt.

The thread here is trying to figure out if temp control is needed after fermentation is over. For me, I ferment in a chest freezer for at least a week, but by then I often want to make room for other brews. So I take out my 1 week old beer out of the temp controlled freezer and leave it at room temp for another 2-3 weeks.

The question is if we would have better beer by keeping it controlled the entire 2, 3,4... weeks of fermentation and conditioning, or if by the end of the first week temp control is simply not necessary and beer can sit at 70 for a couple weeks before packaging.


Tanstaafb, am I missing anything? How's the experiment?

 

[TANSTAAFB]

Sorry guys, I've been meaning to post back for a while but I am smack in the middle of preparing to move to CO for grad school!!!

Here are the Cliff's notes...

4-10 Brew A was fermented in the 5 gal Better Bottle carboy. It was under temp control at 68* for 5 days, was moved to an un-airconditioned room for 2 days but the temps here in Texas climbed into the 90's and I wasn't interested in ruining 4.5 gal of beer! Beer temp never got higher than 78*. So I moved it into the A/C cooled bedroom closet and set the t-stat to 75* for the remainder of the fermentation period (21 days total).

Brew B was fermented in a 6.5 gal bucket and maintained at 68* for the entire 21 days in a fridge with a Johnson A419 digital temp controller.

4-20 First comparison on bottling day...
Both beers look the same as expected.
A-more pronounced bitterness, B-seems cleaner and smoother

Placed all bottled beers in the same warm room (the original fermentation room that got too hot).

5-4
A-almost flat. Still tastes fairly green and bitter
B-decent carbonation (though by no means fully carbed) and lacing. Tastes less green than A and bitterness is less harsh. Head is thin but persistent. Color and clarity is the same.

5-22
Father-in-law and I did a side by side comparison. These beers are now VERY similar but there are differences. Both pour into snifters with a 3" tight white head. Beautiful golden caramel color. Distinctively Belgian in character but the 550 throws more spicy phenols than fruity esters. Very digestable

A- head dissipates much quicker and to just a trace of white on the surface. Can be revived to a 1/4" with a swirl but quickly disappears again. Both of us perceived more bitterness in this beer than in B. No lacing.

B- head dissipates to a 1/4-1/2" which persists. Decent lacing on glass. Taste is clean and smooth. Bitterness supports the Belgian funk from the 550 rather than clashing with it as A does a little.

I expected that the increase in temp would have resulted in a lower FG in A, but it was actually a point higher than B. I was also surprised by how much longer A took to carb up than B. Head retention is clearly better in B and A is perceived as more bitter and a little harsher. That said, unless you are drinking them side by side and looking for differences, it would be hard to tell these two apart.

This experiment was enough to show me that if at all possible, I want my brews under temp control through the entire process. This resulted in a better beer that required less conditioning to reach its full potential. The beer was smoother than its counterpart, carbed faster, and has better lacing and head retention. Both are damn fine beers

 

[emjay]

<EXPERIMENT RESULTS> derka derka derka mohammed jihad </EXPERIMENT>

I wonder how the results would turn out in a double-blind triangle test. Although I'm guessing it would turn out similar to the not-so-scientifically-rigorous experiment you did, with a slight difference only noticeable by direct comparison. If noticeable at all.

And I like experimenting in as controlled a manner as possible and reading research articles and published with the aim of perfecting my process and making beers that are the best I can possibly brew, but I'm largely satisfied with your more casual kitchen-experiment and really don't expect to pursue this issue much further.

Why? Because, if there isn't a significant improvement when the only difference between two otherwise identical beers is that one is kept temp-controlled the entire time, and the other only for the first week or so during active fermentation (ignoring the processes of lagering and cold-conditioning), then it simply isn't worth investing in such capabilities, and I think almost any commercial brewery making over a dozen styles each year (especially those that don't use the same house yeast strain for every single one) would probably agree.

For a number of reasons, I haven't really brewed in about 3.5 months (I'll be starting back up this weekend with a lambic), but usually brew 2-3 times per month, most often 3. Except for a few exceptions, my beers stay in primary for a minimum of 4 weeks, with an average (if ignoring the sours) of perhaps 6 weeks. So at any given time, it's not unusual for me to have 5 beers in fermentors simultaneously (again, ignoring sours), and sometimes even more if I've brewed something huge like a RIS, IPA, barleywine, etc.

But even with just 5 at once, it would be very expensive to accommodate. Yeast is very sensitive to temperature, as we all know, and a beer fermented at 64° is often noticeably different from a beer fermented even 1 or 2 degrees higher or lower. So I'm very particular about the temperature my beer actively ferments at, and refuse to compromise. Since I generally don't brew more than once a week, I can get away with just a single temp-controlled fermentation chamber by letting my beets stay in there for a week or two, and simply move it to my cellar when I need the ferm chamber for a new batch (or some place warmer, sometimes with a brew-belt, if I'm trying to really dry a beer out).

BUT, if I wanted to keep temp control for the entire time I have a beer in the fermentor, since I'm so picky about precise temperatures (meaning I refuse to compromise on a fermentation temperature just so I can stick two different beers in the same chamber), I would need at least 5 ferm chambers, which, as I mentioned before, is a really wasteful investment if it doesn't produce significant improvements. And since everything points to the fact that it doesn't, this isn't really something I care to investigate further, because it's almost certain that the difference is either minor and only noticeable when tasted side by side with an otherwise identical beer, or the difference is not noticeable at all - and because both those possibilities would result in me STILL NOT investing in more than 1 or 2 ferm chambers, the precise answer is, in practice, irrelevant to me.

 

[Jboggeye]

Wow, thanks all for your comments here. This is making me want to do my own experiments, to see how much better the beer would be if controlled the entire time...

 

[63belair]

Hey Tans, thanks for posting back, definitely some interesting results! Good luck with grad school!

 

[bernerbrau]

Glad I found this one. I have an IPA in secondary which I'm debating moving out of the fermentation fridge for 10 gallons of pale ale that I'm brewing next Monday.

Based on this information, I will instead do all in my power to finish up the Stout keg before Monday.

 

[Rahahb]

Did both batches have the same fg?

 

[TANSTAAFB]

Did both batches have the same fg?

Yep. SG 1062, FG 1015. I got 15 on one & 16 on the other, but I consider that within the margin of error for a hydrometer (and user)!!!

 

[cookietruck]

Gotcha. That is the same temp profile I use for all my Belgians. I thought Saisons were warmer starts because of the historically warm farmhouse brewing. I will have to read some more!

i brewed a begian pale ale back in like march/april or something...here in texas.
i just cooled the wort to mid 60's, put the carboy in the house that night, pitched big starter in the morning, temp was right around 70, then left it alone. by the that evening the temp was up around 75. the days following it was up to 77-78.
it finished quick, good attenuation, lots of citrusy and spicy flavors.

i used the begian yeast because i didn't want to bother with temp controls...had just moved into a new house with much work to do.

 

[Tiredboy]

Rather than starting a new thread I thought I might post my question here as I'm in a similar situation. In Jamiaca where "room temperature" is 85F. Been fermenting my first brew (AHS seasonal ale) in an airconditioned room. It's been about a week so far and intend on keeping it cool for the next week or so until I bottle but wondering whether I need to be so concerned about keeping it cool now.

Also, will letting the bottles sit at 85F (for the few weeks until they are drunk) be a problem?