Will yeasts regulate there own temperature?

Hello, I'm new to homebrewing and new to this forum. You can check out my first brew, an all-grain Bee Cave Brewery Kolsch, here.

I live in Montreal and it gets quite cold here in the winter and hot in the summer.

Right now my fermentation room is at around 59-60 degrees F which I think is more or less okay for the style. During the most active part of the ferment, when there was a large Krausen, the temp next to the carboy was ~64 F. Now it is 60 F.

I know for the summer I will probably need to look at a "Son of Fermentation Chamber" or keezer if I want to continue to brew.

But for now, in the winter do you think I should be looking at actively controlling the heat of the fermentation with a heating pad and a temperature controller?

Or is it enough to just insulate the carboy very well and let the yeasts regulate their own temperature.

Yeast produce heat during fermentation but yeast can't keep the beer in the ideal temperature range if it's too cold or too hot in your fermenting area. If the beer gets too cold the yeast will go dormant, if it gets too hot the yeast will produce esters and create off flavors. Temp control is one of the most crucial parts of homebrewing.

They don't regulate their temp. They do produce heat during primary fermentation. So once primary fermentation is over the temp of the beer( I guess you call it beer at this point) will drop to the temp of the room, if this is below the yeasts preferred temps they might drop out of solution.

edit: Jayhem beat me to it

A temp controller will keep you closer to your desired temperature. No control will lead to temperature swings which have the potential to make your yeast flocculate and quit fermenting your beer. You can probably get away with not having temperature control and I will be fine but since you're thinking about building a fermentation chamber for the summer anyway, why not just go ahead and get a controller to use for now?

If this is your first batch, you have bigger fish to fry than fermentation temp precision. Get several batches under your belt and then decide where you want to make changes. Can you give us an idea of your equipment?

itsme6582 said:

If this is your first batch, you have bigger fish to fry than fermentation temp precision. Get several batches under your belt and then decide where you want to make changes. Can you give us an idea of your equipment?

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I disagree. Fermentation temperature control is one of the most important things to address. That is not to say you can ignore other processes. It just should be at the top of the list.

kh54s10 said:

I disagree. Fermentation temperature control is one of the most important things to address. That is not to say you can ignore other processes. It just should be at the top of the list.

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This!
Yeast make beer, without yeast, no beer. Fluctuating, too high, too low temperatures are primary reasons beer does not turn out the way it's supposed to.

Temperature control of fermentation should be a first priority in the quest for making beer!

Thanks for the insights.

So it sounds like I want to keep the temperature at a consistent 68 F for the whole fermentation (3 weeks) until I am ready to crash cool and drop the yeast out.

Alright so my understanding is if I was reading 64 F just outside my carboy during Krausen than the brew itself was warmer on the inside probably close to the 68 F it is meant to be fermenting at.

Now that it has been a few days and the fermentation has slowed (see this picture from yesterday) is it still going to be a warmer temperature in the centre of the carboy than I am reading just outside? Should I still be aiming for 64F outside the carboy?


The carboy was sitting on a heating pad which I kept turned off as it would raise the temp to 70 which is much too high for this beer. I have just now added more insulation between the pad and the carboy hopefully keeping it on low I will hit my temp (which should be 64 F?) without need of a regulator this time around.

Should I be be gently shaking my carboy to wake the yeasts up as well as raising the temp? I am on day 5 of my fermentation.

I have pretty basic equipment:

10 gallon aluminum pot, electric stove, grain bag for BIAB, 5 Gallon Marmite canner for Mashtun heated in oven, floating therm, 6 gal glass carboy. Looking to do 1-2 gallon batches.

duboman said:

This!
Yeast make beer, without yeast, no beer. Fluctuating, too high, too low temperatures are primary reasons beer does not turn out the way it's supposed to.

Temperature control of fermentation should be a first priority in the quest for making beer!

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Is it the up down, up down fluctuation that is bad? If I keep it consistent (well insulated) and it slowly drops is that okay?

The yeast is WLP029 German Ale / Kolsch yeast and my temp is at 60F at the moment (day 5 of the ferment) compared to 64 F (days 1 and 2)

Honestly, the steady temperature is most crucial when active fermentation is going on - i.e. your gravity is steadily dropping as the yeast metabolize sugars. Usually, this is in the first few days of a typical brew.

Once the gravity stabilizes, temperature conrol isn't as big of an issue (large temperature swings are still bad, but minor fluctuations with ambient temp aren't as big of a deal).

yourhuckleberry said:

Thanks for the insights.

So it sounds like I want to keep the temperature at a consistent 68 F for the whole fermentation (3 weeks) until I am ready to crash cool and drop the yeast out.

Alright so my understanding is if I was reading 64 F just outside my carboy during Krausen than the brew itself was warmer on the inside probably close to the 68 F it is meant to be fermenting at.

Now that it has been a few days and the fermentation has slowed (see this picture from yesterday) is it still going to be a warmer temperature in the centre of the carboy than I am reading just outside? Should I still be aiming for 64F outside the carboy?


The carboy was sitting on a heating pad which I kept turned off as it would raise the temp to 70 which is much too high for this beer. I have just now added more insulation between the pad and the carboy hopefully keeping it on low I will hit my temp (which should be 64 F?) without need of a regulator this time around.

Should I be be gently shaking my carboy to wake the yeasts up as well as raising the temp? I am on day 5 of my fermentation.

I have pretty basic equipment:

10 gallon aluminum pot, electric stove, grain bag for BIAB, 5 Gallon Marmite canner for Mashtun heated in oven, floating therm, 6 gal glass carboy. Looking to do 1-2 gallon batches.

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Keeping the temperature at 68 for all 3 weeks isn't necessary not even beneficial. You want to keep the temperature low for the initial fast part of the ferment because that is where your off flavors develop but keeping it too cool will cause the yeast to slow down and they may not finish the job. I like to keep my ambient temperature between 62 and 65 (the yeast will heat up the fermenter a bit during this) until the majority of the sugars are gone and then after perhaps a week or a little less I let it warm to the low 70's to encourage the yeast to finish the ferment and do the cleanup. By this time the flavor is pretty much set and I don't have to worry about off flavors any more.

RM-MN said:

I like to keep my ambient temperature between 62 and 65 (the yeast will heat up the fermenter a bit during this) until the majority of the sugars are gone and then after perhaps a week or a little less I let it warm to the low 70's to encourage the yeast to finish the ferment and do the cleanup. By this time the flavor is pretty much set and I don't have to worry about off flavors any more.

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1up!

Raise it a couple of degrees at the end to clean up Diacetyl etc. especially in a nice light, clean Kolsch

RM-MN said:

Keeping the temperature at 68 for all 3 weeks isn't necessary not even beneficial. You want to keep the temperature low for the initial fast part of the ferment because that is where your off flavors develop but keeping it too cool will cause the yeast to slow down and they may not finish the job. I like to keep my ambient temperature between 62 and 65 (the yeast will heat up the fermenter a bit during this) until the majority of the sugars are gone and then after perhaps a week or a little less I let it warm to the low 70's to encourage the yeast to finish the ferment and do the cleanup. By this time the flavor is pretty much set and I don't have to worry about off flavors any more.

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This is my process for almost every recipe with ale yeast. I always start in the low 60's and ramp up to low 70's after 4-7 days

Unibrow said:

This is my process for almost every recipe with ale yeast. I always start in the low 60's and ramp up to low 70's after 4-7 days

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I will 3rd this. I find that if I keep the ambient temp around 61F for the first 2-3 days and then slowly adjust my temp controller up 2 degrees per day until it's up to 70F in the fermenter by day 7. My beer seems to taste the best if the active fermentation happens right around 65F (beer temp).

I suggest that you put your fermenting vessel in a water bath and buy an aquarium heater i think the one i got was around $20 it has a temperature regulator built into it. there are different wattages, obviously the higher the wattage the more warming power you have. you can insulate your whole setup with a blanket or something.

Jayhem said:

I will 3rd this. I find that if I keep the ambient temp around 61F for the first 2-3 days and then slowly adjust my temp controller up 2 degrees per day until it's up to 70F in the fermenter by day 7. My beer seems to taste the best if the active fermentation happens right around 65F (beer temp).

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Well since the ambient temperature has remained between 59F and 60F since Krausen.

I think I will follow Charlie Papizian's advice for now and "Relax, Don't Worry, Have a Homebrew"

I'll look into ramping up the temp with the heating pad tomorrow when I hit day 6.

Thank you all for all the help so far.

A lot of people on this forum will assert that you cannot make good beer without temperature control. That's simply not true. Yes you will want to pay attention to style (don't brew a farmhouse that wants to ferment at 80 degrees when your basement is 50). I brew a lot of great batches with ambient temps between 55 and 80 in my basement. I've actually spent a lot of time worrying that batches are not going to come out well during the extreme temperature times because of the advice on this forum. In my experience Great beer is possible with proper procedure and planning without temp control (if you can't keep it in the 80s or above 50 I might be worried). Don't create problems that don't exist.

This thread is way off target. Ferm temp control and no starter. First batch and your being told to give it a diacetyl rest. Just be patient. Give it a good 3 weeks before you do anything. Don't shake the carboy. If you can't wait, go buy a new fermentor and make another batch to keep yourself occupied.

Gartywood said:

A lot of people on this forum will assert that you cannot make good beer without temperature control. That's simply not true. Yes you will want to pay attention to style (don't brew a farmhouse that wants to ferment at 80 degrees when your basement is 50). I brew a lot of great batches with ambient temps between 55 and 80 in my basement. I've actually spent a lot of time worrying that batches are not going to come out well during the extreme temperature times because of the advice on this forum. In my experience Great beer is possible with proper procedure and planning without temp control (if you can't keep it in the 80s or above 50 I might be worried). Don't create problems that don't exist.

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While I will not discount what you are saying as to some degree it can be true, it really is not best practice. Even if you are selecting styles and yeast to brew within the constraints of your ambient temperature the yeast, fermentation and final product will be improved with temperature control from the initial growth phase to packaging.

The fact of the matter is this thread is in the beginner's forum. New brewers have no concept of temperature control, much less selecting styles to brew determined by the constraints of the yeast selected. Hence the reason why so many posts in this area pertain to off flavors, stuck fermentation, beers that taste like s&$%&t, etc. Honestly, most are trying to brew ales and IPAs and can't understand why their beer turned out the way it did when they fermented it at 75-80 degrees.

Personally I think it best to try and guide new brewers to use best practice and educate them so as they become more experienced they can adapt their process to what works best for their system and the types of beer they choose to brew

^ +1 If needed, do the research. Find out where you're yeast strain does best, then do your best to allow it to happen. The yeast will do better, and you'll be happier with the results.

You are doing a Kolsch, using Kolsch yeast with ambient conditions in the low 60's....that's perfect! Kolsch is an ale that wants to be a lager. A long cool fermentation is desirable. Don't rush your Kolsch. It sounds to me like you have done a nice job with this one....I love Kolsch