I plan on doing a little shopping around this weekend for a chest freezer that I can use as a fermentation chamber. I would like to safely fit as many of my carboys in the freezer as possible. I generally have about 3-5 batches in either primary or secondary at a time. I have one 6.5 Gallon, three 5 gal, and two 3 gal carboys. If you have a converted chest freezer, what are the dimensions of the freezer and how many carboys can you fit in there at a time? Aside from a digital temperature controller, is there anything else I would need to maintain consistant temps?
(I have googled this question, but most folks use there freezer to serve beers as well and I already have a keggerator so I wouldn’t use it for that purpose ;D)
I’ll have to take the measurements when I go home, but mine fits 6 carboys easily and has room for my stir-plate with a starter on it. Depending on where you live and where in your house your chest will be located, you might want a 2-stage controller and a heat source. Mine is in my garage and in winter it uses the heater a lot more than the freezer (i just use a heat-pad). Obviously if you are in Florida or Arizona or something like that you will have no need for the heater.
As for shopping around, I would watch Craigslist; I got mine about 2 and a half years ago for $100.
My chest freezer is only 5 cu ft so it only holds 1 carboy at a time. I have a 2-stage Ranco controller and a Fermwrap to control the heat. I taped the fermwrap to the side of the freezer and the temp probe get place on the outside of the carboy and covered with bubblewrap.
My 14.7 cu ft holds 2 6.5 gallon and 2 6 gallon carboys. I also have a 5" muffin fan inside that circulates air continuously. I just scored a 23 cu ft for $70. No telling how many that will hold ;D
I was given a big old chest freezer. Don’t know the deminsions, but it will easily hold 6 buckets, and my stir plate. I use a small space heater, and tape the temp probe to one of the carboys. The one problem is I like to brew different beers, and many call for different ferm temperatures. If they are too far off from each other, I just average them. But, mostly stick to 67 degrees for 7 days, then I raise it to 70 for two days, and keg it up. It works well for me.
Slightly off topic, but the HomeBrewTalk Forum has a good thread on how the various household freezers hold corny kegs. http://www.homebrewtalk.com/f35/sizing-your-chest-freezer-corny-kegs-75449/
Many of these are converted for dispensing and a few for fermenting and lagering but you will get a good idea on their sizes.
My expirence is: buy a new freezer. Used ones (likely old) may not stand up to the treatment of a controller. (on & off more frequently) and get the extended warrentee. Also, buy the biggest one you can afford. You can use the room for fermenting and lagering and storing kegs (if you keg). Homebrewing is another habit that can keep you upgrading equipment. Soon you may be like me and have 2 large freezers. One for fermenting pilsners (50 deg.F) and the other to lager (33 deg. F) and store my 20 kegs. My .02