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Author Topic: Fermentation Temps  (Read 2721 times)

Offline wamille

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Fermentation Temps
« on: December 28, 2010, 07:51:36 pm »
Ok... I'm guessing I'm ignorant.  I always assumed that fermentation temperature referred to the temperature of the location where the fermentor was located.  So, if the fermentation temperature for a given yeast was listed between 65 - 72 degrees, I figured the termperature of the room where my fermentor was located had to be between 65 - 72 degrees.  So from what people are tellling me on the forum, I need to adjust my fermentation temperatures to include a 10-degree factor to allow for the heat generated from the fermentation activity?  So the room where I'm conducting my fermentation has to be between (in my example) between 55 - 62 degrees???  I'm a bit confused.  Then all my beers have been brewed way above the proper temperature range... however, I've had very few beers that tasted bad in my opinion.

Any input would be appreciated.

Offline Hokerer

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Re: Fermentation Temps
« Reply #1 on: December 28, 2010, 07:58:41 pm »
Then all my beers have been brewed way above the proper temperature range... however, I've had very few beers that tasted bad in my opinion.

But just think, get your fermentation temps under control and they'll taste even better !

And 10 degrees is probably the absolute max you'll ever see but if you account for that then you'll be fermenting in the lower part of the yeast's range which is best.

Offline majorvices

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Re: Fermentation Temps
« Reply #2 on: December 28, 2010, 08:30:23 pm »
Get a stick on "fermometer" - they are surprisingly accurate (within 2 degrees of my thermowell usually). Fermentation, including fermentation temperature, is probably the most important thing you can do to improve your beer. If you think your beer is great now you are going to be really surprised when you start managing fermentation. Temperature is only part of it. This also mean pitching enough healthy yeast. See the pitching calc. at to get an idea how much yeast you need to pitch for every batch.

Offline bonjour

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Re: Fermentation Temps
« Reply #3 on: December 29, 2010, 07:21:42 am »
If you don't have a cooler room a swamp cooler will give you several degrees of cooling,

a wet tee over your fermenter,  doesn't look as good as it would on your girlfriend but it does the job.

I'll second the stick on thermometer, it's accurate enough.  Think about it, the yeast only care about the temp they are at, not the room temp, and +5 is more typical.  You get a greater temp rise at higher temps (more favorable for yeast growth, remember you are not growing yeast, you are making beer, and with higher gravities, more food for the yeast)
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Offline bluesman

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Re: Fermentation Temps
« Reply #4 on: December 29, 2010, 07:52:04 am »
The wort temp and room temp are both important. The first order of business is to get the wort down to pitching temps which in the case of ales would be in 60ish range. The next thing to consider is the ambient temp of the environment around the fermenter which should ideally be at the same temp. This is usually accomplished through the use of a fermentation chamber like a swamp cooler or a chest freezer, etc...
Ron Price

Offline seajellie

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Re: Fermentation Temps
« Reply #5 on: December 31, 2010, 08:45:11 pm »
I'm guessing that lagers at 50 degrees ambient are less likely to drive the temp much beyond 50, when compared to ale yeasts sitting at 72 ambient pushing that ferment past 72, all else being equal. No data or science to support that, just my wag at this point.

This same question has really been bugging me over the last year, so I recently installed a thermothingy on my plastic bucket fermenter. In two lager ferments sitting in a controlled fridge in the basement, neither batch got more than 2.5 degrees above the current fridge temp at any point in fermentation (ferm temps 48 - 51 at all times). This was measured on one NIST certified thermometer, and one calibrated to that one. The probe was sitting at the 3.3 gallon mark in a five gallon batch, almost dead center of the bucket. The controller was not attached to the fermenter internal probe.

I'd expect that an ale fermentation at 72 is significantly more exothermic due to the higher metabolism, and that the heat can't be dissipated as quickly. Of course, there are other factors: OG, fermenter geometry and material,...

oh jeez, it's almost new year's. how ironic that a hobby that makes you a sure invite to parties is also the same hobby that can drive you into a trappist monk-scientist mode. Happy New Year! I'm off.

Offline Kaiser

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Re: Fermentation Temps
« Reply #6 on: December 31, 2010, 09:10:39 pm »
Yes, all things being equal, the more heat that needs to be dissipated in a given time the greater the temperature difference will be.

You can even judge the fermentation intesity by the difference between the fermenter and ambient tempereture.


Offline matt

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Re: Fermentation Temps
« Reply #7 on: January 01, 2011, 05:49:32 am »
Yes - when you look at a yeast package or recipe and it gives the fermentation temperature it is talking about the wort and not the ambient room temperature. Get a stick on thermometer and a regular room thermometer. Place the room thermometer next to your fermentor and see what your difference is. At my house it's about 4-6 degrees - a little higher in the summer. There are simple and easy ways to knock off a few degrees. If your beers are tasting pretty good now maybe lowering the fermentation temps by a few degrees will be the difference between good and great.

Offline rbclay

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Re: Fermentation Temps
« Reply #8 on: January 08, 2011, 07:58:26 am »
Make sure you chill your wort to a few degrees lower than than the temp you want to ferment at. I can only speak to my experience, all with ales.
If you want to ferment at 64F and your ambient (room) temp is 68-70, you need to pitch at 62. The temp in the fermenting wort will rise.
If your room temp is 60 (corner of the room, basement, whatever) and you want to ferment at 64, you still need to pitch under 64. If you think the "cooler room temp will drop the fermentation so I'll just pitch at 70 and it will drop", you are mistaken. Not only will it stay at 70, it could still rise a few degrees. Now you are fermenting a beer as much as 10 degrees higher than your target. You just made a different beer.
The stick on thermometers (fermometers) are a good idea. And get a couple regular room thermometers. You may be suprised to find the difference from one part of your room/house to another to be more than a few degrees.
If you have the resources just keep brewing, take meticulous notes, and compare and contrast what you find. Have fun...
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