Fermentation chamber a major flop

I just built a "mother of the fermentation chiller" based on this design:

Fermentation Chiller

I deviated from the design somewhat ... Instead of the recommended 2" thick sheets, I used two 3/4" sheets glued together with a 1/4" air gap between them. And of course my cut tolerances aren't great. I plugged major leaks with caulk + liquid nails, but some small leaks remain.

The end result performed horribly! I could see an immediate drop in temp (~3 degrees) when I turn on the fan (PC chassis fan) but the chamber temp never got below 70 F. (Room temp is only 75 F). And the ice in the bottom section melted almost completely within an hour or two.

Maybe I'm not using enough ice, or blocks were too small?
Seals too leaky?
Fan too small?
Or too much heat generated from the initial fermentation couldn't be overcome?

Has anyone had success with this design?

On a different note ... my beer languished at 74 to 76 F for about 24 hours with vigorous fermentation before I moved it to the old fashion bucket + water + towel + fan method... Should I expect off flavors with this short high temp + very active fermentation?

Thanks
BigCask

i just built the very same one over the weekend. I used 2" styrofoam from Lowe's which had a foil backing on it (I constructed my chiller with the foil to the inside). I used duct-tape to put everything together and also used it to seal all the cracks. I really wasn't too worried about efficiency, and I hastily put it all together, but I still ended up working really well. With the fan running constantly I was able to drop the chiller from 72 down to 55 in about 2 hours. keep in mind I didn't have anything in my chiller at the time I tested, however. i'm sure this makes a difference too.

What I did notice, though, was that it took a LONG time to start dropping the temperature. I chalked it up to the surfaces having to be cooled down. There's a lot of surface area inside the chiller, and for all of it (plus the air space) to be dropped a significant amount it's going to take quite a bit of ice and time.

That being said, what temperature did your fermenter start out with when you placed it in the chiller? Did you "pre-chill" your chiller by starting it up before placing your fermenter inside it?

Jtucker,

I'd like to hear your experience once you have a carboy or two in there ...

I didn't precool the chamber nor did I test it in advance. So two 5 gallon carboys of 75 degree beer is a pretty tough first run, as that's a huge amount of thermal mass to overcome.

Re: the empty chamber test... I really question whether that's a meaningful real world test. Now that I've admitted defeat (for this batch at least) I'll have to test with plain water and see if this project is salveagable. What really sucks is that the 3/4" foam more than doubled the difficulty of the project. I may have to give it another go with the 2" sheets, though it seems that it's not readily available here in Houston.

-BigCask

Why not just pick up a used freezer on craigslist and a Johnson temp controller? I spent $75 total for this setup last year and it works great.

the "real test" won't be until this coming weekend. I'm still getting together my equipment as I've decided to switch to all grain and I will be trying my first batch. i hadn't done any temperature controlled fermentation as of yet, so I'll be venturing out into new territory myself.

BigCask said:

Re: the empty chamber test... I really question whether that's a meaningful real world test.

Click to expand...

yeah, I did just to try to get familiar with everything before I installed the thermostat. after staring at the digital thermometer for quite a while (with nothing happening) I got frustrated. once I did finally get the temperature down I could take the door off for a few moments to check things, and it took significantly less time to drop the temperature back down once I replaced the door.

keep in mind it wasn't anything scientific, but I just kind of figured it was due to the chiller being too "hot" to start with.

BigCask

I ran into the same trouble when building mine, it seems that down here 2" insulation is impossible to find and somehow gluing 2 3/4" sheets together makes a mess of things.

Your initial problem was probably the starting temperature of your beer, if you had continued the ice for longer, you may have eventually cooled your beer down. that design is better at maintaining fermentation temperatures rather than actually cooling that mass down to those temperatures.

I overcame this by using a small mini fridge instead of ice. I am able to cool my wort down those last 5-10 deg before pitching, and I can maintain temperatures quite well. I even did my first lager earlier this year in it! There is a link down in my signature that has a lot more information about how I pulled it off, but if you have any more questions I can try to answer them!

deathweed said:

BigCask

I ran into the same trouble when building mine, it seems that down here 2" insulation is impossible to find and somehow gluing 2 3/4" sheets together makes a mess of things.

Click to expand...

+1

I used 2 3/4" sheets glued together and it came out pretty messy. I am thinking the best way to use 3/4" sheets would be to line the inside of a cabinet/locker or something rigid with them.

With that said, if you were able to get the 3/4" sheets glued together with an air gap between, it should be quite insulated. You can fill any large leaks with some expanding foam insulation. 5 gallons of wort + a carboy is a very large thermal load. Cooling down a bit further might make the ice last longer.

For most styles of ales, I don't think you will have any issues with off flavors at 75 degrees. Most all of my brews have fermented at 70-75 w/o issue.