Fermentation Chiller v2

At my old place I had this beast of a fermentation chiller:


I lagered in the chest freezer, and had a second thermostat and fans to pull air so I could maintain proper temps for ales in the foam insulation box. Unfortunately, when I built it I didn't think much about getting it back out of the basement. It was assembled downstairs, and when I moved the only way to get it out was to cut it in half.

Anyway, saturday I finished building my workbench, and between limited room in the garage and the inspiration provided by TwoHeadsBrewing's setup, I figured I could make the best use of the space available to me.
The space it'll go into under the workbench:


I was trying to figure out how to make the best use of the two pieces I had from the original. I had more insulation, but no sense in wasting what I already have:

Once I figured out the best arrangement, I started by cutting the old pieces to even the edges and open up the middle:


Once I had most of the pieces cut and test fit, it was time to start assembling:


All seams were joined with caulking or liquid nails, and then taped over with foil HVAC tape just to be sure:


In the old chill box, the carboys would settle into the foam, making them hard to move, and every time I moved one in and out the foam got a little more dinged up. Again stealing TwoHeadsBrewing's ideas, I put down melamine board for the flooring:

Gratuitous action shot (yes, I know I shouldn't be using my tailgate as a sawhorse):


Front panels cut and attached:


And finally, got the door hung:


Anyway, ran out of time so that pretty much wrapped it up for sunday. Still on the to-do list:
Insulate the front, basically the door and the panels on each side.
Re-attach the collar to the chest freezer.
Run ducting from freezer to chill box.
Hook up fans and thermostats.
Put weatherstripping on the door.

I haven't done much testing since most of my carboys are full at the moment, but I'm anticipating being able to fit 4 carboys, and should have some leftover room for a couple sixpacks or a conditioning keg.


Edit: can premium members have more than 4 pix in each post? It was a pain breaking this up (and I've learned a lot here) Maybe it's finally time to pony up

Nice build! Good idea on using the HVAC tape on the seams...I think I'll have to steal that idea for my box as well . I'll have to make the trip over and see it in person...and of course bring over a growler of my dry-hopped house pale for the admission fee.

Looks great! There have really been some great ideas floating around here lately.

You can only post 4 pics at a time even if you pay.

That's efficient use of space, doing it under a workbench..

sweet now i know where mine is going.

Well the project that was supposed to be done in just over one weekend ended up stretching out to more like a month. Mainly just because I haven't been getting my lazy bum over to the hardware store, but finally got that fixed over the last few days.

Anyway, the original plan was to pull cold air from a chest freezer w/collar using computer fans and a thermostat. When TwoHeadsBrewing was visiting during my last brew day, he asked why I wasn't just using a window mounted AC. It was like the clouds opened up and a ray of light shined down. My old place had no central air, but now that i've moved I had a stack of three window mounted AC's just sitting in the garage. I've seen many threads where people have used them, but never even made the connection.

Anyway, the newest one (and therefore most energy efficient) will go down to 62 degrees on the built in thermostat. Perfect for ale temps, and since I have the separate chest freezer I'm set for lagers too. The A/C also has an "energy saver" mode, and when that's activated the fans ONLY run during cooling, otherwise the unit shuts down completely. That works great for 24/7 operation, since my other AC's run the recirculating fan constantly, regardless of whether the compressor is going.

So now, on to the pix!
Unit plugged in for testing, I'm going to need to figure out a better route for the wiring:


Closeup. I just cut a new hole in the insulation and sealed it in with silicone:



From inside. I haven't decided yet whether I want to duct the output away from the inlet, or just leave it as-is. I think i'll probably be fine. Right now I have to poke my head into the ferm box to change temps, but I'm trying to find the remote for the AC so I can change while there's carboys in the way:


11 gallons of Smoked Imperial Porter doing it's thing. You can see the old air inlet and return behind the carboys. I just glued some leftover insulation over the opening:

YES! That looks like a great setup, and from what you describe you won't even need an external temp controller for it? Does it keep the temp pretty steady?

yep, no external temp controller needed, just so long as I want to stick with ale fermentation temps. I'm going to need to wait for it to warm up some more to really test, but it looks like the AC has a fairly narrow temp range it maintains. Every 10 minutes or so it will fire up for 30 seconds or so then shut back off.

That is a sweet set up. Nice work!

Long term follow-up: over the last few months of use, ambient temps have ranged from the 60's to some extended stays over 100. The little AC unit is still chugging along. The kill-a-watt is giving me an average cost over the last 80 days of approx 25 cents a day. Not too shabby.

very impressive

i lived in chico for a while so know how hot those summers are

great set up

i too have a couple of free window a/c units now that i have recently upgraded to central a/c

ive been having trouble keeping fermenters under 70 in swamp baths even here in the bay area

ill be giving this more thought

thanks and well done

CaliBrewin said:

very impressive

i lived in chico for a while so know how hot those summers are

great set up

i too have a couple of free window a/c units now that i have recently upgraded to central a/c

ive been having trouble keeping fermenters under 70 in swamp baths even here in the bay area

ill be giving this more thought

thanks and well done

Click to expand...

I wish we'd stop getting these heat waves and the temperatures would stay consistent. Oh, and woohoo for another Sunnyvale brewer!

MBasile said:

I wish we'd stop getting these heat waves and the temperatures would stay consistent. Oh, and woohoo for another Sunnyvale brewer!

Click to expand...

In Berkeley my ferm. temp. might get up to 79F one day and down to 55F the next! i've had to move my carboys to a friend's house in So. SF just because its always foggy and cold over there (consistent at least). Might have to look into building one of these fermentation chiller dealies. . .

wow that is pretty slick.

Will the AC unit get you down to lagering temps? Also does the carboy closer to the AC get a lot colder than the one farthest away?

I have to say I was dead set on building a son of fermentation chiller, but having seen this, I may use my 2"EPS and invest in a small window unit and build out some shelving I already have in my garage. Suddenly seems much easier than swapping ice jugs and for pennies a day!

Couple questions about this if you don't mind though. I think I'd probably build a much smaller chamber, simply due to space constraints, but I'm wondering how many btu's the a/c you used is? Also, is it safe to use an a/c like this in an enclosed garage? I have a side door that gets opened almost daily so I don't think ventilation would be an issue but want to make sure. Just wondering about anything the unit might give off into the ambient air of the garage that could be dangerous - ozone, carbon monoxide, etc...

Thanks in advance! You just inspired me to take a step back and rethink what I'm doing!

Sorry to bump an old thread...

I always have an issue with my cellar temps getting too hot in the summer and am scared to do ales. I have an old mini fridge that still works. I am thinking of converting this into a chiller (need to build a box to fit my carboys of coarse). Any advice on doing this?

banks412 said:

Also, is it safe to use an a/c like this in an enclosed garage? I have a side door that gets opened almost daily so I don't think ventilation would be an issue but want to make sure. Just wondering about anything the unit might give off into the ambient air of the garage that could be dangerous - ozone, carbon monoxide, etc...

Click to expand...

The only thing off the back end of the A/C is hot air. Each time you chill the box a bit, you will also heat the garage a bit..