Heat of Fermentation

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Netflyer

Supporting Member
HBT Supporter
Joined
Oct 29, 2009
Messages
776
Reaction score
9
Location
Near Benedict Maryland
If you have a yeast that has a spec. of 65 to 75 degrees, that is the heat of the fermenting wort right? The heat fermentation generates counts right? So if the room is 70 and the fermentation is occurring at 74 I'm not at the middle range but instead at the upper range of those yeast, regardless of the room temp, right? I mean granted after 72 hours and the vigorous fermentation ends the temperature drops back to 72 and w/in a week it is at ambient temp. So, what do you state the fermentation temperature as being?

Pitch at 70, warms to 74, back to 70 (ambient) after 1 week. Keep it in the fermentor for another 2 weeks at 70. Do those 2 weeks count and figure in to the fermentation temp, or do you just consider those few vigorous days when stating the fermentation temp?

Thanks!
 
Sometimes I have to keep my fermentation fridge at 63 to keep the fermentation at 68.... The temperature range for the yeast isn't the ambient temp, but the fermentation temp. Most of your off flavors from the high temps is from the fermentation cycle itself. After fermentation is complete the ambient/fementation vessel temp is of less importance. So, I try to make sure I control the temperature during the fermentation (usually the first week...sometimes longer). After that I move the carboys outta my chamber to make room for more..
 
Or a big tub of water... which will help control fluctuation in temps (think thermal mass) especially if you drop in a frozen water bottle or two.
 
Yes, very doable... so what has been your experience, in say a 65-68 ambient basement, how cool will a tub of water with a few frozen water bottles in it keep the fermenter?

I'm usually running up to 72-74 w/heat of ferm. will water and ice keep me at 68ish? I can pitch at 68 easy...
 
Yes, very doable... so what has been your experience, in say a 65-68 ambient basement, how cool will a tub of water with a few frozen water bottles in it keep the fermenter?

I'm usually running up to 72-74 w/heat of ferm. will water and ice keep me at 68ish? I can pitch at 68 easy...

My house usually has an ambient of 68-70 (according to our thermostat, anyway). With a swamp cooler (tub of water+t-shirt draped over the fermenter) I can get and maintain pretty much any temp from 60-70. It takes a little bit of practice to learn how many frozen water bottles you need in the water and how often you need to change them to maintain a certain temp, but overall the system works great.

So, yes, water and ice should very easily keep you at 68ish. My guess is that the first time you try you'll add too many frozen water bottles, and when you check a few hours later you'll be shocked to see how low the fermentation temp is (that was my experience, at least!).
 
I'm brewing an Fuller's ESB clone this weekend and the Wyeast 1968 would love 65-68. I'm going to go for it with the swamp cooler, thanks for the advice/help!

If the ambient of the room is at 64-65 and I'm using a standard 'ale pale' 6.5 gal. fermenter and I pitch at 68 do you think room temp water in that 64-65 range will hold her, or maybe just a few ice bottles? Does the water have to be significantly colder than ambient?
 
By house is at 73 upstairs...Basement around 70.


Before i got my ferm chamber going, I went to wally world and got me a tub a little longer than 2 carboys. was like 12 bucks. Fill h20 in the tub bout inch-2 deep.

Throw 2 water bottles in " 16.9 - 20oz works great " Check temp in 2 hrs. It should drop your carboy down to about 65-67.

Change out water bottles morning and night for the first 4 days usally, basicly till ferment stops..Then the cold water will keep the temp down.

IF the temp got to high during the active fermentation, I would take the shirt and just dunk it in the h20 and that seems to help a bit.

There is a downside to this, After everything is done...You have a tub full of water you have to take care of..... Dont forget it one day when your in a hurry and leave it in the walkway and your swmbo goes down to the dark basement and steps in ice cold water.....:mad:

Hope this helps
 
Fill h20 in the tub bout inch-2 deep.

2" deep? I was thinking deeper. I'm clueless..:drunk:

So then, this is the picture I have in my little head..

1. Take my rubbermaid bucket and put in 2" of water.

2. Put a tee-shirt over my fermenter and put it in the tub w/the water.

3. Drop in a few plastic soda bottles with ice in them...

4. Change bottles 2x a day

Do I have it?
 
Yep, although I usually put a bunch more water in the bin, about 3 gallons' worth. I usually pour into the bin whatever sanitized water I've used on brew day (some sanitizer keeps mold from growing - or at least that's my sense; I could be wrong), the ice water I use from my pre-chiller, and then some more water to reach ~1/3 - 1/2 way up the fermenting bucket. Toss some frozen water bottles in and you're good to go.

You'll figure out what works for you after doing it a few times, but I think you've got the general idea.
 
I should clarify by 2 inch of water....
It is 2 inch's up the side of the carboys
With the long "tub" i have it takes about 3 gal of water or so to get the 2-3 inch of water up the side of the carboys. the tub is only about 6 1/2 inchs high but it works like a champ. Everybodys setup differnt.

Just "play" around with what ya got and you will quickly find out what works best for you.

Good luck :)
 
Cool, thanks for the clarification - it all makes good sense. I've heard of people strapping their fermenters in streams to keep the temp down... seems risky to me - I think I'd always go outside and be 1/2 surprised to even see the fermenter still there...

I'm swamp cooling this weekend thanks to you guys!
 
So how are you guys taking the fermenting brew's temperature? Are you running a long thermometer in the airlock hole, or what?
 
I always just assumed those things were a gimmick. If it is stuck on the outside of a warm plastic (low thermal conductivity) bucket, immersed in a cool water (high thermal conductivity) bath, or covered by a really cool wet T-shirt saturated with evaporating water, isn't it going to constantly read low?

Has anyone benchmarked the stick-on thermometer with a direct reading of the liquid inside the fermenter?
 
I have an infrared thermometer, in my experience the temp inside and outside the fermenter is about the same even with a plastic pail, so the stick on fermometer should give you a good reading.

If you use a 5 gallon water bath for a 5 gallon batch, and room temp is 68*F, your water bath will be about 66-67*F due to evaporation, and your fermenter will be about 68*F inside. If, on the other hand, you just stick the ale pail in the 68*F room it will get up to 74*F or 75*F inside.
 
I have the opposite problem in the winter, my basement air is 65, but the basement floor is less than 60, so any carboy sitting on the concrete goes dormant due to heat conducting through the bottom. Any carboy sitting on a shelf or a book does just fine.
 
I also use the "water in tub" method in my unheated basement. Using ice bottles, it's easy to regulate temps in the summer. In the winter, I use a adjustable 100W aquarium water heater. The water heater is very useful to bump up the temp for belgians and for a lager's diacetyl rest.
I also add a touch of star san to the water if it is going to be in use for more than a week.
 
I recently posted something that you might find helpful. In summary I found that trying to control fermentation temperature (especially ales) is very difficult if you are using glass or plastic fermenter - say you want to ferment at 68F so you put your fridge at 68F - problem is some ales will drive the fermenter temperature up as much as +6F. Due to the laws of heat transfer, it is much better to place the glass or plastic fermenter in a temp controlled water bath. The fermentation will always be within 1 degF of the temp of the water. Here is the link.

https://www.homebrewtalk.com/f11/water-jacketed-fermentation-chamber-145194/
 
I have my 2nd beer in my swamp cooler and for the second time I have a batch that hasn't been above 68 even with heat of fermentation. Wyeast 1028 had no trouble bubbling away at 68 nor did 1968. I'm really excited to taste these in a few weeks, they not only represent my first under 70F fermentations but also my first two 'full boil' batches. Needless to say I have high hopes :)
 
Thanks for that tidbit, I'm going through my first winter of brewing and my basement floor will get that cold in the next few months, the 'book' method sounds great!

:mug:

The spot near my basement door is usually around 60-62F from Nov-Mar. A towel on the floor under the carboy serves as a suitable barrier to achieve my 65-66 temp target. A little tougher in July when the temps are 100F outside. I've gotten use to drinking lagers in the winter and ales and stouts in the summer.
 

Latest posts

Back
Top