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General Category => Equipment and Software => Topic started by: rbowers on March 04, 2011, 12:34:45 PM

Title: Fermentation Temperature control
Post by: rbowers on March 04, 2011, 12:34:45 PM
I'm looking to better control the fermentation temperatures of my beer.  Right now I have a bit of a drafty house and temperature can vary a bit.  I've looked into some carboy warming gadgets as the basement (where most of my brewing takes place) stays about 60 or sometimes a bit cooler.  The fermwrap heater seems to be a reasonable choice.  Does anyone have experience with this?  Also with regards to the controls will a Johnson Digital Thermostat control do the trick with the aid of a thermowell stopper?  Any advice or recs would be appreciated.
Title: Re: Fermentation Temperature control
Post by: gordonstrong on March 04, 2011, 01:02:47 PM
Have you checked the temperature variation in an interior closet?  If you keep the door closed, you shouldn't see swings like you do in a big room.  Get a digital thermometer that records and saves hi/lo readings and see if you have much change.  If it's going to stay in the basement, do you have any warmer spots, say near the heater?  You could also build a little box out of rigid insulation or styrofoam that you could put around your carboy.

A carboy full of fermenting beer has a lot of thermal mass, so it doesn't swing around in temperature as much as the surrounding air does.  If you add another level or two of buffering to those air changes, the air next to your carboy won't change as much either.  Also keep in mind that a carboy of fermenting beer will throw off heat as it ferments (fermentation generates energy), so if you do insulate your beer, it will keep heat in as much as keeping temperature change out.

Worry less about the air temperature and more about the temperature in the fermenting beer.  That's what affects yeast performance.
Title: Re: Fermentation Temperature control
Post by: dbarber on March 04, 2011, 01:44:46 PM
I tend to keep my house cool during the winter so my SOP is to use the fermwrap, a glass carboy, carboy cap with a thermowell and a digital temp controller.  It works great!
Title: Re: Fermentation Temperature control
Post by: bluesman on March 04, 2011, 02:49:13 PM
Great suggestions so far. I ferment in my cellar which ranges as low as 58F in the dead of winter and as high as 70F at the peak of summer. I use a large box that fits over my fermenters to mitigate drafts and tempeperature swings. I recently fermented a barleywine at 60F ambient temp. I chilled the beer down to 60F and pitched the yeast. The fermentation increased the temp to 65F after three days and the beer fermented from 1.112 down to 1.024 in two weeks.

Sixty degrees is really not too low for most ales. The only potential issue is that certain yeasts like to ferment a little higher which can be accomplished by some slight modifications as descibed.

There are fermenter adhesive strips that are inexpensive and are fairly accurate. They can attach to the outside of the fermenter to enable one to monitor the beer temp during fermentation.

http://www.rebelbrewer.com/shoppingcart/products/Fermometer-Liquid-Crystal-Thermometer.html
Title: Re: Fermentation Temperature control
Post by: denny on March 04, 2011, 03:59:38 PM
I do pretty much what Gordon describes.  I ferment in an interior closet in the guest room.  I keep the fermenter in a tub of water to add extra mass to buffer thermal swings.  If it gets too cold in the winter, I use an aquarium heater in the water.  If it gets too warm in the summer, I put ice packs in the water.
Title: Re: Fermentation Temperature control
Post by: rbowers on March 04, 2011, 10:36:55 PM
I tend to keep my house cool during the winter so my SOP is to use the fermwrap, a glass carboy, carboy cap with a thermowell and a digital temp controller.  It works great!

Do you use the Johnson digital temp controller and if so does it work well with the Thermowell?
Title: Re: Fermentation Temperature control
Post by: dbarber on March 05, 2011, 11:00:48 PM
I have used both the Ranco and the Johnson digital and both work well.