Fermenting Fridge vs Freezer

[David20Hersch]

I have been doing a lot of research but haven't found any answers for a few questions.

Some people say that you can lager in a fridge but I also read that commercial breweries lager at close to freezing. Is it fair to say that a freezer could get the job done better??? most fridges can't get down to 32F


Also how do people put multiple fermentation vessels in one Fridge/Freezer. A temp probe can only read one FV at a time so how would i know that the others vessels are getting the proper temps? brew styles that have relative fermentation temps?

 

[NervousDad]

You can easily lager in a fridge, most get down to the mid 30's. I prefer a fridge because the temp changes are slower when correcting for the hysteresis that you set on the controller.

For multiple fermentations, you can set the temp of the fridge to a temp slightly lower than the required fermentation temp. Then put heat wraps on each carboy, but you'll need a controller for each.

 

[Kent88]

I've fermented a few lagers in a larger dorm fridge (1 gallon carboys) and while I've read that you want to lager as close to freezing as possible I lagered in the range of 35F-40F. My munich-hallertau smashes tasted pretty good, IMHO.

As for the probe placement, I either just go for ambient or I put it close to one FV and figure that the other will be close. If you really want to know the temp of each FV, you could make your own controller with a few DS18B20 temp sensors (or ask someone with some arduino experience) as you can put several of them on one line, but I fail to see the benefit.

I'd go with a freezer if I could, but besides space I have no complaints about what I have now. Even when I get a chest freezer to customize I think I'll keep my fridge for ales, and maybe keep washed yeast in there.

 

[mrgrimm101]

I bought a garage fridge that I use for my bottles (SWMBO was tired of all the beer in the house) and I also use it to cold crash sometimes. If I cranked the cold up, I have no doubt that it could get below 30F without any sort of modifications. I found the fridge for about $100 on Craigslist. If you're looking for a lager chamber of sorts, this could be a good route. It's when you have to bring the temp up higher for ales that you should consider rigging up a temp controller of sorts.

 

[azazel1024]

Honestly the differences in the rate of precipitation between 32F and 35F are very minor.

Beyond that, most upright fridges on the coldest setting will easily get below freezing in them (unless they have automatic cut-outs to prevent the fridge temp from dropping below 32F). Dorm fridges when you convert them, even without upgrading insulation, will definitely get below freezing. Mine set on coldest, WITHOUT having removed the built in thermostat/controller will push below 20F when cranked. My upstairs 19cu-ft upright fridge on 4 of 8 temp setting holds at about 36F in the fridge. Out of curiosity I had set it to 8 of 8 once, it hit about 30F and everything was freezing up in it.

A freezer is going to be better insulated, but it'll also take up more space and unless you are lagering for really long times or constantly have something going, the price difference between running a converted minifridge and a chest freezer are minor (pro-tip, only lager for 2-3 weeks for most beers, call it 3-5 weeks for a really heavy lager).

My 3.6cu-ft dorm fridge was easy to convert (I think it took me 40 minutes, not including putting a temp controller together). This included removing the door bits, adding foam board to the door, bending the cooling panel out of the way and installing an 80mm fan to circulate the air while running. It'll fit a 6 gallon carboy in it so long as you use a blow off tube and/or "remote locate" the airlock (it's about 2" too small to fit an airlock on top of a carboy).

My 4.5cu-ft converted dorm fridge took a little longer to convert, because it was 2 pains to get the cooling panel bent out of the way. It has room for a bit more foam insulation inside of it. It can fit 2x3 gallon carboys if they are really friendly or a 6 gallon carboy with ease.

I would at some point like to get some reflectivix to attach to the inside of both fridges to up the insulation some more, but that is because I am weird, not because either actually need it (the smaller will hold 118F fine for kettle souring at around 60% load on my 40w paint can heater and it'll hold 35F for lagering and cold crashing just fine at maybe 35% load on the compressor. The slightly larger one is roughly similar numbers).

 

[David20Hersch]

would a small wine fridge get cold enough!?

 

[azazel1024]

Do not get a wine fridge. They often have peltier coolers, which are terribly inefficient. In addition they generally only get down to about 40F. Plus you'd really want to up the insulation a lot (a glass door, not so well insulated). They are designed to keep wine around 50F or so.

I mean, if you could get one for FREE, maybe. But since you could probably score a 3.6-4.5cu-ft dorm fridge for $30-70 of Craigslist, I'd just go that route.

Oh, for your initial question, this is why I use dorm fridges. You cannot be sure it is keep in the beer at the right temp. Now if you are brewing a 10 gallon batch of something, sure that is more than fine to throw it in the same cooling vessel as the temp between the two carboys should be very, very similar. If you are brewing something different, the temps are likely to very, either because of yeast activity or because the different strains of yeast need vastly different temperature requirements.

I occasionally will throw two 3 gallon carboys in my larger minifridge. However, when I do, I am generally splitting a batch to test something out, but they are brewed at the same time and likely have pretty similar requirements (two English Ale yeasts). On rare occasions I'll brew two different batches on different days and use the one fridge if the other one is full. But I'll generally brew them far enough apart (at least 3-4 days) where it might not be as big of a deal. Example, I brewed a Schwarzbier on a Saturday and then on Tuesday I brewed an English Pale Lager, but used the same German Lager yeast and I just moved the temp probe from the SB to the EPL when I stuck it in there. They both turned out great, but I was also fermenting near the middle of the temp range, so when the EPL was really active, it probably made the SB a couple of degrees cooler than it "should have been". I had it set at 50F, but if I were to guess, the SB probably got pushed down to 48-49F while the EPL was super active in fermentation.

Fortunately Lagers tend not to ferment as fast, therefore don't throw off as much heat.

I've seen ales push temps up by an easy 4-5F above ambient during super active fermentation, but it looks like lagers are more like 2 or maybe 3F (and the SB was still fermenting, so it would have been putting out a small amount of heat, even when the EPL was putting out a lot more).

I do a lot of carboy rotation though. Like right now I pulled the Pumpkin ale out, to throw a Hefe in, then I just pulled the Hefe out to put the Stout in. I'll use the other minifridge to cold crash the Pumpkin ale so I can bottle it this weekend. Then I'll pull that out to put the Hefe in to warm it up to about 72F for a day or two before I cold crash it and bottle that. Once that is done the Stout will probably be ready to warm up to 72F for a day or two and then cold crash and bottle it.

My basement isn't quite warm enough yet to maintain 72F without my heater in the fridge (~69F).

It was a real "joy" when I had 5 beers going all within 8 days of each other. A couple did the "ferment at ambient" game, but fortunately my basement was cooler than (67F, 64F on the slab).