How harmful are low ferment temps?

It's been discussed quite a number of times here and some people worry about fermenting "too low."

IMO, fermenting at very low temperatures will offer no ill affect, it will simply make the beer cleaner. it make take longer to ferment and you may have to rouse the yeast again, but the only risk you are running is causing the yeast to go dormant. This doesn't stress them, from my understanding, and simply raising the temp and rousing them will fix the problem.

In my experience, the only thing that "stresses" yeast and causes off flavors is very high fermentations, or rapid temperature fluctuations (inconsistent temps)

In any case, i'd much rather experience a slow or stuck ferment from temps below the recommended range than esters and phenolics from temps above.

What are your thoughts and experience on the matter?

I've always been taught that lower is better, for exactly the same reasons you mentioned....cleaner taste, less ester production. less chance of getting a headache from the beer...

I know that the brewmeister of Rogue ferments pacman between 60 and 70 degrees depending on the beer...but says he prefers doing it at 60 degrees...

I have found that each yeast has a sweet spot temperature and that it is best to err on the side of colder temperature. I wish new brewers would pay more attention to this and we would have a lot less fermentation problems and "off- flavors" to fix. The other problem is none of the new brewers want to let the beer stay in the primary long enough to finish cleaning up after the main fermentation.

Well, one problem could be a slower starting fermentation could lead a new brewer to infection depending on sanitation practices and the amount of lag time. Agreed though, that warm fermentation is much more costly to a brew than lower if you are good with sanitation.

This season I fermented 3 weizens cold - 15-17*C. They taste very good, but I see strange over-attenuation effect. They get down from 13 to 2 Plato, maybe they yeast mutated somehow in such cold temperatures.
The last batch - roggenbier stays now 3 weeks on primary, it has 2.5 Plato and airlock still bubbling.

I had no problem with lagtime. With proper pitching they start in couple of hours.

I agree with WBC in that every yeast is different. I know that I really prefer my Cal Ale strains (only used 001 and S-05, never 1056 yet) below 65. But I'm also using these for things were the yeast flavor isn't necessary. I just pitched close to a 4L starter of straight slurry at 57. I'm hoping it will take off - I want to see how low I can get it to work. I've heard as low as 50.

On the other hand, the Saisons I've made where I pitched and fermented right at 80 has a fantastic pepper spice with some subtle background citrus. It attenuated down to 1.010, as well. I pitched this same yeast into a different Saison at 68 and did the ramp up thing. The spice is still there, but it only attenuated to 1.018. So in terms of flavor profile, they are very similar, but it greatly affected attenuation.

I really want to try the Hefe yeast (WY3068) at 62, which is what is recommended by Jamil. Maybe do a side by side with one that low and another around 70 and see how the flavors are affected.

Within the livable range of the yeast (and yes, certainly at the upper and lower limit of its temp range you will select for mutants) The temp will affect the flavor profile. So its really a matter of taste - a estery flowery beer will benefit from a higher temp.

giligson said:

Within the livable range of the yeast (and yes, certainly at the upper and lower limit of its temp range you will select for mutants) The temp will affect the flavor profile. So its really a matter of taste - a estery flowery beer will benefit from a higher temp.

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I agree that it depends on the beer style/yeast. For beers that you don't want much of an ester profile or are using a fairly neutral yeast (think Pale Ales or Notty) cooler is probably better, if longer. O nthe other hand if you want something with more of an ester or yeast flavoring (Belgians/Hefe's) mid to upper could be better to an extent

I agree that fermenting at the lower end avoids a lot of potential problems with stinky off-flavors. Just to offer a slightly different take, I've also heard various brewers (including some well-respected Belgian brewers quoted in "Brew Like A Monk") advocate upping the temperature towards the end of primary fermentation to help dry out the beer. I've used that technique and (anecdotally, at least) it gives very good results. According to Jamil's podcast on big-ass Belgians, the more funkiness you want from your yeast, the earlier in fermentation you'd ramp the temps up. But starting low seems very widely taken as a good idea.

Ok....now I'm thoroughly confused. I moved my two carboys upstairs to a room that is 69 because my 'brew room' in the basement was hovering around 62.....One has a Hoegaarden clone form AHS with Belgian Wit Ale 400 (White labs) that's been in the primary 11 days and the other is a SA Cream Stout clone from AHS with the White Labs English Ale 002 that I brewed yesterday and is already starting to bubble in the blow off... Should I move 'em back downstairs? Or move just the Hoegaarden since I think it finished the major fermentation yesterday?

you can move them if you'd like. the one that will get the most benefit is the stout...primary fermentation is when most of the flavors come out.

in the future i'd keep them all in the basement...that temp is perfect.

Thanks for all the advice about cooler temps. I have my 4th batch a hefe in a brew closet in a basement that has recently stabilized at 62. All my previous beers had been at 70-74 and I was worried the cool temp was detrimental since the fermentation was slow to take off and has dragged on longer than I expected. I was planning on taking a grav reading today since its day 8 but I still have a thick krausen on top. Any advice as to how long to leave this in primary and wether or not to secondary before bottling. Thanks

If you still have a krausen, leave it alone. When the krausen falls, take an SG reading and see where you are compared to your target SG.

I cool every beer to 55-57, pitch the yeast and slowly let the temps come up to about 65 through the first 3 days. It keeps my beers pretty clean

I used to ferment at whatever temps the living room was... sometimes over 74 degrees. Now I use a fermentation fridge, and I do my ales at 62. It never new I had off flavors until I brewed cooler and compared. Much cleaner beers.

Before my temp control, all of my beers a very similar flavor... now they are unique and I can taste that in them.

What about "sleeping yeast"? I have a porter that I pitched around 70. 12 hours later, it was blowing through the top. It did this for 2 days at 68*. Then my temp dropped(slowly) to about 64. After no activity in 1 day, I took a reading of 1.020.. I warmed the ferm up using a cooler, water, and a aquarium thermometer to 68. Right away I get activity in the airlock, and have for the past 4 days!! This is day 9 and still perking away.

Are you saying that I would eventually get to the same number at 62* ?

lrr81765 said:

Are you saying that I would eventually get to the same number at 62* ?

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It depends on what the active temperature range of your yeast was, but I'd say probably yes, you would eventually get there at 62 degrees. Generally speaking, fermentation happens slower at cooler temps and faster at higher temps. The problem with excessively high temperatures is that they can give stinky off-flavors, and the problem with excessively low temperatures is that the yeast can go dormant and stop altogether (and need to be swirled and warmed a little). But most ale yeasts would still be active at 62, and would probably give a clean fermentation at that temp. That may or may not be a good thing depending on what style of beer you're making, but I've fermented beers at 62 and they came out fine.

lrr81765 said:

What about "sleeping yeast"? I have a porter that I pitched around 70. 12 hours later, it was blowing through the top. It did this for 2 days at 68*. Then my temp dropped(slowly) to about 64. After no activity in 1 day, I took a reading of 1.020.. I warmed the ferm up using a cooler, water, and a aquarium thermometer to 68. Right away I get activity in the airlock, and have for the past 4 days!! This is day 9 and still perking away.

Are you saying that I would eventually get to the same number at 62* ?

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CO2 dissolves better in colder temperature and as it warms up it comes back out of solution. I would guess that fermentation was mostly over.

Airlock bubbling is not a gauge of fermentation.

lrr81765 said:

What about "sleeping yeast"? I have a porter that I pitched around 70. 12 hours later, it was blowing through the top. It did this for 2 days at 68*. Then my temp dropped(slowly) to about 64. After no activity in 1 day, I took a reading of 1.020.. I warmed the ferm up using a cooler, water, and a aquarium thermometer to 68. Right away I get activity in the airlock, and have for the past 4 days!! This is day 9 and still perking away.

Are you saying that I would eventually get to the same number at 62* ?

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with a good pitching rate, healthy yeast and a good environment with a consistent temp, yes.

you can always rouse the yeast, too. so many people are afraid to introduce oxygen, but once fermentation begins there is a huge cloud of co2 protecting your beer. there's no oxygen in there.

i say, AS SOON as fermentation slows down a bit, give that sucker a swirl. tell those yeast to quit slacking and get back in the party. it can only help.

bamadoh said:

Thanks for all the advice about cooler temps. I have my 4th batch a hefe in a brew closet in a basement that has recently stabilized at 62. All my previous beers had been at 70-74 and I was worried the cool temp was detrimental since the fermentation was slow to take off and has dragged on longer than I expected. I was planning on taking a grav reading today since its day 8 but I still have a thick krausen on top. Any advice as to how long to leave this in primary and wether or not to secondary before bottling. Thanks

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i'd just leave it in the primary for a total of 2-3 weeks and then, assuming your gravity is down, straight to bottle. hefeweizen krausen likes to stay there even after fermentation is complete. it may indeed be finished fermenting.

DeathBrewer said:

i'd just leave it in the primary for a total of 2-3 weeks and then, assuming your gravity is down, straight to bottle. hefeweizen krausen likes to stay there even after fermentation is complete. it may indeed be finished fermenting.

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Thanks for the info. Funny thing is this hefe was a very slow and inactive ferment from what I can tell even though all I read said to expect violent fermentation so I set up a blow off tube that never was needed. Then Saturday I brew a simple pail ale with dry yeast and by Sunday night its going so strong I had to move the blow off tube to it and clean up my air lock. Guess you never know just how the yeasties will behave.

they are some unpredictable little buggers!

DeathBbrewer, Your thoughts are welcome on the following:

I'm a newbie with this situation: room temp 65 daytime to 54 nightime temps during fermentation of a pale ale with Safale S-04(Recommended temperature range: 64ºF-72ºF). reading this thread it shouldn't be an issue or is it just to cold. The room is a pantry closet, so a light bulb and or blanket might get it a little warmer. Or should i just brew it and stop worrying about temps!

Pale Ale II extract from Morebeer
Willamette hop flavor and Cascade hop aroma. liquid malt (8 lbs), Crystal malt (1.5 lb) and hop flavor (4 oz in finish).

Estimated Original Gravity: 1.065
Estimated Alcohol Percentage: 6-7%
SRM (Color Range): 8.5
IBU's: 76.4


And yes i like your fermentation cabinet

artyusmc said:

DeathBbrewer, Your thoughts are welcome on the following:

I'm a newbie with this situation: room temp 65 daytime to 54 nightime temps during fermentation of a pale ale with Safale S-04(Recommended temperature range: 64ºF-72ºF). reading this thread it shouldn't be an issue or is it just to cold. The room is a pantry closet, so a light bulb and or blanket might get it a little warmer. Or should i just brew it and stop worrying about temps!

Pale Ale II extract from Morebeer
Willamette hop flavor and Cascade hop aroma. liquid malt (8 lbs), Crystal malt (1.5 lb) and hop flavor (4 oz in finish).

Estimated Original Gravity: 1.065
Estimated Alcohol Percentage: 6-7%
SRM (Color Range): 8.5
IBU's: 76.4


And yes i like your fermentation cabinet

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If you really go down to 54 degrees ambient that will make the US04 go dormant...you need to rig a way to keep the temps consistent and above 60...like in a swamp cooler with an aquarium heater submerged in it.

thanks revy

i've been lurking around alot and see alot of your post, so i'll take your advice. My wife might miss her heating pad thou. I want to start this first batch right

so room temp fluctuates between 54-65°F over a 24-hour period...what is your FERMENTATION temperature at during this time? being liquid and conducting it's own heat, it probably maintains a much more consistent temperature.

fluctuating temps and high tempeartures can negatively affect beer...low temperatures will only make it cleaner.

you still don't want it to fall dormant, tho, and i'm not sure how s-04 works (used only a couple of times)

i'd say get one of those fermometers that you can stick on the side of your vessel and keep a record of the temps. if it's jumping up and down, you'll want to get some kind of control. if it's maintaining within a few degrees, you're good.

you PROBABLY want to keep that yeast in the 60s, at least. not many ale yeasts do well any lower, although nottingham can kick some ass in the low 50s.

DeathBrewer said:

so room temp fluctuates between 54-65°F over a 24-hour period...what is your FERMENTATION temperature at during this time? being liquid and conducting it's own heat, it probably maintains a much more consistent temperature.

fluctuating temps and high tempeartures can negatively affect beer...low temperatures will only make it cleaner.

you still don't want it to fall dormant, tho, and i'm not sure how s-04 works (used only a couple of times)

i'd say get one of those fermometers that you can stick on the side of your vessel and keep a record of the temps. if it's jumping up and down, you'll want to get some kind of control. if it's maintaining within a few degrees, you're good.

you PROBABLY want to keep that yeast in the 60s, at least. not many ale yeasts do well any lower, although nottingham can kick some ass in the low 50s.

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Actually I'm going to take temp readings of water over 24 hours, to see flucuation. This ale is not brewed yet but intend to ferment in a pale ale bucket over 3 weeks.

thanks for quick reply

that's a good test if you haven't started yet, but remember that your fermentation temps could easily rise up to (or possibly more than) 5 degrees above the water temp.

i'd definitely get a fermometer for your ale pail.

i'd definitely get a fermometer for your ale pail. [IMG said:

http://somethingwine.com/Merchant2/graphics/00000001/fermometer-bucket.gif[/IMG]

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yes I will deathbrewer and a wort chiller and a brutus and a...

As soon as my wife gives me more money for morebeer stuff.

Thanks for the five degrees raise in temp i was wondering that, as i was doing it.

https://www.homebrewtalk.com/f14/3-wired-digital-thermometer-82194/

much better then fermometer

Pivzavod said:

https://www.homebrewtalk.com/f14/3-wired-digital-thermometer-82194/

much better then fermometer

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thats a good idea

how is it so much better? does it actually give you more accurate readings than the fermometer? do you stick it inside your fermenter and wouldn't that make it a PITA to sanitize? it's obviously much mroe expensive.

do you have something that compares it to a fermometer? i can has results of test pls?

My preference is to get the yeasts started fairly high in their temp range, and once the activity is high, then drop the temp down to the low range and let it finish there. Takes longer, but that way I get the benefit of a fast start, and lots of healthy yeast, and also less chance of off flavors later on.

I like my beers dry and clean. Preferred yeast is Nottingham.

Lately I try to keep the waterbath around 50-55F for the first couple of days, then I let it warm up to 60F-65F. I usually let my beers ferment for 3 weeks to ensure that the nasties are cleaned up.

The yeast reproduction stage (first 24-48 hours) is when the most funk is created. Minimize the funk and you'll get a clean tasting beer. I guess it depends on what you are trying to accomplish.

I am really glad to hear all the glowing reviews of Nottingham and its work in the lower 60s and 50's. I havea pale ale fermented with Nottingham and its been sitting in a brew closet with a fermometer reading of 60 for two and a half weeks. Because of this thread I have just let it sit. I will take a grav reading at 3 weeks and then hopefully bottle soon thereafter. I was a little worried that the yeasties may have gone dormant but I will trust in you guys since you have never steered me wrong so far (5 batches in).

DeathBrewer said:

how is it so much better? does it actually give you more accurate readings than the fermometer? do you stick it inside your fermenter and wouldn't that make it a PITA to sanitize? it's obviously much mroe expensive.

do you have something that compares it to a fermometer? i can has results of test pls?

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I stick it on the outside (doh!!!) and its accurate to 2-3 degrees from my tests. I've had a fermometer on my Coopers bucket, I agree with this for how accurate it is - https://www.homebrewtalk.com/f11/how-do-ya-read-fermometer-strip-50274/

As far as price, a stick on thermometer goes for $2.99 at AHS, I guess a penny more for a digital thermometer that can read it more accurately, can show you everything in real time, easier to see, can read from distance, works with F/C is a bad deal.

You do the math!

Pivzavod said:

I stick it on the outside (doh!!!) and its accurate to 2-3 degrees from my tests. I've had a fermometer on my Coopers bucket, I agree with this for how accurate it is - https://www.homebrewtalk.com/f11/how-do-ya-read-fermometer-strip-50274/

As far as price, a stick on thermometer goes for $2.99 at AHS, I guess a penny more for a digital thermometer that can read it more accurately, can show you everything in real time, easier to see, can read from distance, works with F/C is a bad deal.

You do the math!

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so...how did you test it?

i have an internal/external thermometer that i taped to my carboy when i used my fermentation chiller. that way i could view it without opening the chiller. i found them to be a match to the fermometer every time, so i'd say they were pretty accurate.

i didn't realize those were so cheap, tho. might have to pick up a few and use them the same way

I did a batch on Saturday and I tested with my other digital cooking thermometer (posted about it somewhere) and checked my wired thermometer and it was 2 degrees lower. I tested the wort inside the bucket & compared it to reading outside the bucket.

Check out how I have my cooler closed and wire sticking out

https://www.homebrewtalk.com/f39/newbies-2nd-batch-some-diy-cooling-chamber-85133/

bamadoh said:

I am really glad to hear all the glowing reviews of Nottingham and its work in the lower 60s and 50's. I havea pale ale fermented with Nottingham and its been sitting in a brew closet with a fermometer reading of 60 for two and a half weeks. Because of this thread I have just let it sit. I will take a grav reading at 3 weeks and then hopefully bottle soon thereafter. I was a little worried that the yeasties may have gone dormant but I will trust in you guys since you have never steered me wrong so far (5 batches in).

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Heh. I had my fermenter sitting in a 48F water bath and Nottingham was still working. Ferment it cold!

i just had 15 gallons finish out in 4 days with nottingham fermenting at 54°F. this beer is gonna rock!