Craft The Perfect Draft: Chest Freezer Fermentations

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I have been using my BrewsBySmith Fermentation Kit for about nine months now and it has undoubtedly become an integral part of my brewing process. I've grown so attached to the way I can set it to accurately control the temperature of my fermenting beer that I won't ferment another batch of beer without one. Here in the Northeastern United States the temperature outside plummets during the colder months of the year. Even though my garage brew room is well insulated the temperature inside can still get down to 45F in the dead of winter. Using the 32 watt Fermwrap heater that came with the kit, together with a homemade 100 watt 'paint can' heater, the controller was able to maintain a stable 66-72F temperature range with ease. This worked out really well and over the winter and I was able to produce a number of different styles of beer that turned out great.

7.0 Cubic Foot G&E Chest Freezer
Up until this point I had been fermenting my beer inside an insulated wooden fermentation chamber I had built a number of years ago. The fermentation chamber wasn't powered and it needed to be fed a steady supply of frozen water bottles in order to keep the fermenting beer cool in summer. But in the colder months the heaters, combined with the digital controller, did an excellent job of maintaining the perfect temperature range throughout the entire fermentation. The BrewsBySmith digital controller I use is the dual stage model and has the ability to alternately energize both the heating and cooling outlets as needed to maintain a desired fermentation temperature. So I decided to invest in an electric chest freezer and connect it to the digital controller's cooling outlet in order to maintain fermentation temperatures accurately during the summer.

Dual Stage Digital Temperature Controller
I had to make sure the freezer I chose to use was going to be big enough inside to fit two 6.5 gallon plastic fermentors and a paint can heater in it comfortably. After making a cardboard template using the widest part of a fermentor lid I set out to test a few freezers and see how they measured up. I was relieved to find that the G&E model #FCM7SHWW 7 cubic foot chest freezer fit my needs perfectly. It was even small enough to fit inside my small SUV for the ride home saving me on delivery charges and having to wait for it to be shipped to my address. The salesman at the store reminded me to stand the freezer upright for three hours to allow the oil to drain back into the compressor before plugging it in. I had to lay the freezer on its side to fit inside my car and evidently that caused the oil to run out of the compressor which in turn could lead to issues if plugged in right away.

Chest Freezer Fermentation Chamber In Action
Once the freezer was in place and plugged into the digital controller all that was left to do was to brew up a batch of beer and test it out. I placed the Fermwrap on the floor of the freezer and plugged it into a short extension cord used to connect the paint can heater to the heating outlet of the controller. The temperature probe sits inside the thermowell and plugs into the rear of the controller too. I also ran a temperature probe to another digital thermometer to monitor the ambient air temperature inside the freezer to note the differences between the beer and air temperatures. With the lid of the freezer raised the extension cord and temperature probe wires were easily routed underneath it to the outside. I couldn't be any more pleased with the results of using this chest freezer in combination with the dual stage controller. The combination of freezer and heaters held the temperature of the fermenting beer well within a single degree temperature swing throughout the entire fermentation. It's a really good feeling knowing I'll be drinking some perfectly fermented beers all summer long now.
Vince Feminella [aka: ScrewyBrewer]
[email protected]
As someone who has built one of these myself, a word of advice: get a dehumidifier and put it in the chamber when you are brewing. The first time I fermented and ale (68 degrees), I opened it up three weeks later to find everything dotted with mold.
Does anyone know if this would fit 2x 6.5 gal PET or glass carboys?
@drthrob thank you for pointing this out. I did notice a small puddle of condensation at the bottom of the freezer and the air inside felt very damp. I'm going to have to take your advice and use something to absorb or eliminate the moisture, I was hoping there was another option to running a dehumidified too though.
These work to absorb the moisture in a ferm chamber:
I keep two in my chamber. They work great during regular fermentation, but need a little help when the freezer warms up after a 32 degree cold crash.
For removing condensation, an Eva Dry works okay but I have found that "Dri Splendor Silica Gel" inside an old sock or panty hose works just as well and is much cheaper.
I use a single EVA dry that is sized for a 400 sq ft room and it works great. I just take it out and recharge it when I take the beer out to keg. It is ready in 24 hours for another batch. I do wipe out extra moisture from the chamber when I put a new batch in.
I have the same, exact freezer and love it.
I bought 2 humidifiers and they have worked like a charm. Good suggestion.
I also bought a small, computer fan and keep the air flowing and haven't had to defrost at all.
Minor editorial nitpick:
"I placed the Fermwrap on the floor of the freezer and plugged it into a short extension cord used to connect the paint can heater to the cooling outlet of the controller."
Don't you mean the HEATING outlet of the controller?
I am usually opening my chest freezer to get or put something else into it at least 2-3 times a week so I usually just run a towel around and inside of it to get any puddles/condensation out when I do that. Works well for me.
@drthrob thank you for pointing this out. I did notice a small puddle of condensation at the bottom of the freezer and the air inside felt very damp. I'm going to have to take your advice and use something to absorb or eliminate the moisture, I was hoping there was another option to running a dehumidified too though.
How would one lift a full fermenter into or out of a chest freezer? Rumor has it there are "old fart" brewers out there who might not be able to perform a physical lift.
And a recirculation fan (old PC fan repurposed) will also help both with temp stabilization as well as humidity management.
(oh, beer lord beat me to it)
@ThreeSheetz I would recommend enlisting the help of someone not quite so 'fartfull' to assist with the heavy lifting. Or try rigging up a rope and pulley system to help out.
2 PET 6.5 gal containers fit perfectly in my 7 cu. ft. GE. The PET big mouth bubblers as well, with room on the hump for a blow off container.
One (hard lesson learned) bit of advice...these work amazingly well, and go from ferment temp to cold crash with the push of a button. BUT!!! remember to take the blow off tube out of the container before cold crashing or you'll find out just how much nasty water can suck back into your ferment container with a sudden temperature change.
@ThreeSheetz, I think you're gonna need a pump. Put the fermenter in empty and pump in the wort. Then when it's done, pump out the beer.
I went with an old refrigerator. If you take out the door shelves and and interior shelving and build a very simple platform to put the buckets or carboys on, you have a ton of room and it is much easier to get the full vessels in and out. Used fridges are cheap on Craigslist and they have a smaller footprint than a chest freezer too.
2 PET 6.5 gal containers fit perfectly in my 7 cu. ft. GE. The PET big mouth bubblers as well, with room on the hump for a blow off container.
Good write up. But instead of a "paint can heater" I picked up a ceramic warming lamp from the local pet store. It is meant to keep reptiles warm so it gives off plenty of heat without any light.
This is one of the best investments any brewer can make. I built my own STC-1000 controller and use it with an upright freezer for fermentation. During the winter months, I use a small ceramic heater that the STC-1000 controls as well. This always keeps my fermentation temps in check.
In my keezer, I use an EVA-Dry 500 that sits on top of a wind tunnel I built that circulates air inside. This keeps things nice and dry in the keezer. I actually have 2 EVA-Dry's so I rotate them out with my keg changes so that keeps them "thirsty".
Nice write-up Screwy!
OK, would someone please clue me in to the "paint can heater" he's using? The only paint can heaters I've ever heard of involve a roll of toilet paper stuffed in a paint can and soaked in alcohol. Great for an ice fishing shack, maybe not so good inside a fermentation freezer!
For a chest freezer, dehumidifier or a re-engergizable desiccant. For a minifridge where you have a "discrete" cooling pad/coil, you can put something like a tiny ice cube tray under it to catch condensation run off.
My minifridge for ales produces so much condensation, I might have an ounce or two of water to empty from the try for a 6-8 day ferment (frankly I just leave the door open when done and let it evaporate on its own without emptying it). For lagers, a 2 week lagering tends to fill the ice cube tray to the brim. Summer time, it'll overflow. So I'll check and empty about once a week with summer lagering. Produces maybe 5-8oz of condensation a week in the summer and 3-4oz a week in the winter (ice cube tray is pretty small, holds maybe 8oz of water total).
Get a new 1 gallon paint can at your local hardware supply store. Comes with no labels. Then get a ceiling light fixture electrical box. Attach to lid of can. Install a 40-100w light bulb to it, attach lamp cord to the light fixture box. Plug in.
I think it cost me $18 in parts to build one. I run a 40W incandescent in it and it can keep my 3.6 and 4.5cu-ft minifridges (with very mild insulation upgrades) at a toasty 118F when it is 65F in my basement (sour kettling). Granted, when the wort was 90F, it took probably 12hrs to actually hit and maintain 118F when warming 5 gallons of wort up. But next time I'll be a little smarter and make sure that the wort is closer to 118F first.
I also spray painted the outside and inside of the can black (because it is "raw" aluminum, which has a really crappy emissivity for something like this, so that bulb inside will get a LOT hotter than if you spray inside and out black, which will absorb the visible and IR light a lot better, as well as re-radiate it a lot better).
@Puddlethumper I documented the paint can heater build I did and you can view it using the link below...
I used an old clamp type utility light, some aluminum flashing I had on a shelf, a bit of duct tape and an old school 100 watt light bulb to make mine. It works perfectly and cost me my time since I had all the parts laying around anyhow.
Thanks guys. Hadn't run across that one before. And here in sunny California our biggest issue is keeping things cool rather than warm. I appreciate the tips.
Eva dry helps, just get a giant jug of Damp-Rid and replace it as needed.
I use a small fan heater and don't have moisture problems. When its on, its moving air around. It's only a 200 watt heater and the size is smaller than a paint can (about 4" x 5" x 6"). I believe its called "My Heat" and I got it on Amazon for less than $20.
I'm cold crashing 10 gallons of Orange Sunshine Witbier this morning after a two week fermentation. I was surprised to see the inside of the freezer was dry too. During primary fermentation there was moisture buildup inside but it seems to have been dried up now. The inside of this freezer is all aluminum so rust won't be a problem but mold buildup still is a legitimate concern.
My STC-100 Temp Controller hooked to my Wine Cooler was the best addition to my homebrew arsenal. Looks like you have quite the setup as well. Thanks for the article.
@Conman13 I can confirm that 2 Glass 6.5g carboys do not fit inside. I usually go with one glass, one PET...Solid compact chest freezer overall, though.
Fermentation produces a fair amount of humidity in an enclosed space as some of the wort/beer is evaporating as you have the CO2 percolating through it. When CO2 production stops, you don't have that percolation increasing evaporation.
Probably why you had the moisture build up during fermentation, but not cold crashing.
@drthrob good thing my wife gave away my small dehumidifiers.... good pointer, i always have moisture in my chest freezer
Inkbird makes a much better digital contoler, Its a stc-100 but with C or f. Makes a world of difference if you think in F like me.
@ScrewyBrewer Go to amazon and search for Eva-dry Renewable dehumidifier. They are wireless, and last 10 years. Works GREAT!! Has a meter on it that tells you when its full (takes about a month) then you plug it in, it dries the material inside the housing, and you can use it again and again. They are only $20 - $30 too! Also, if you put a fan inside to keep the air circulating (preferably from top to bottom) that will help as well.
Why place the fermwrap on the floor? It was my understanding fermwraps needed space around their outside so they didn't overheat. Is that true or an overblown concern?
I too have made use of a thermostatically controlled fridge controlled by the STC1000.
Purchased the fridge for less than $50. For the heating device I made use of the butter conditioner which came as a standard feature of the old fridge.
I made use by firstly removing the conditioner unit, then removing the heating wire. Made a basic heating pad by arranging the wire in a spiral pattern using hot glue gun sandwiched it between thick paper/ thin plastic coated cardboard.
Carried out a 'load test' by filling fermenter to 23L noting the start temp. Then powering up the make shift heater. Saw that the rate of heat increase was something around 0.5deg C/Hr. Not fast I know, but its does - that was the main goal!
As this is a refrigerator, it is by design, pretty much immune from excessive condensation build up, as the evaporator has a drain underneath it.
So far so good.
@eko wrapping a fermwrap snugly against the fermenter will ENSURE no hot spots occur. This is because the fermenter absorbs the heat generated.