Brewing_In_MKE wrote:how did you make your cooler/water bath fermentation chamber?
60qt igloo cooler, filled with water to about two inches below wort level, place underneath air conditioner vent in cool-ish basement. I swap out one frozen water bottle in the morning, and I can easily maintain 60F. If fermentation is going strong, it's a water bottle in the am and then another in the late pm. I've got a cheapo thermoprobe taped to the side of the my 6 gallon better bottle and an lcd thermostrip and they're both within 2 degrees of each other, so I'm pretty confident of my temp. Super cheap, super simple, although the 60 quart igloos are hard to find now. I've got three, but I'm going to use the third for my BBQ (to keep the foil and towel-wrapped brisket warm!
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Next step is going to be seal the cooler with the fermenter (foam top with hole drilled for air lock) and then use PVC to connect a smaller cooler filled with ice. Computer power supply to spin a computer fan inside the PVC to blow iced air through pvc based on Ranco set-point. I've got all the gear, but I don't have a good way to cut through the cooler wall. But since this is working out so well -- and is pretty low-impact -- I'm not in a hurry to rig up the full-blown fan. I think one cooler with ice should be able to supply two fermentation coolers (each connected with fan via PVC).
Even without the air conditioner vent, I can still do 62F with one small frozen bottle, 60F with two large Smart-water bottles, and can dip way low to 58 or so with a frozen half-and-half container in the water along with the bottles.
No towels or t-shirts or even a top on the cooler. Just the 5gall fermenter in with I'd say maybe 2 gallons of water (3/4 up the fernmenter's side).
The first few times I peeked way too much at the temperature, but I realize between the wort and the cooler water, it's a *very* slow swing -- even when fermentation is going strong. I'm fermenting a Honey Brown Ale I did two days ago w/Pacman. I went to bed last night and it was 61F (ambient 64), woke up and it was at 62.5 or so. Swapped out the water bottle, and it was back down to 60.5 before I went to work. I expect it'll be around 61.5 or so when I come home from work. Mid-week, I'm confident the fermentation will be mostly over, and I'll be able to use just one bottle every 24 hours (if that) to maintain 61-62F or so for the rest of the fermentation over the next three weeks.
My other cooler has the pump/heater/ranco -- and it's steady at 74F. It dips to 73, the Ranco kicks on, and after three hours, it's back to 74. It took about 24-36 hours to raise the 3787 from 65F pitching temp to 72F after three days at 65F. I worried that that might be too fast a swing, but we'll see. If so, I'll redo the batch and ramp it up 1-1.5 degrees per 24 hours (which is essentially just hitting a button on my Ranco). The Patersbier started a bit strong -- 1.070, but it's down to 1.020 after 6 days with only a slight -- very slight -- bannana taste. If I didn't specifically look for it, I probably wouldn't peg it as bannana -- more like a mild spiciness. I'm hoping this gets down to 1.012 or so (no incremental feeding of sugar).
I'm using an old Radio Shack digital thermometer for the ambient temp control (velcro'd) to my basement wall. And I'm using these nifty little digital thermometers duct-taped to the side of the fermenter (above the water line) and a LCD thermostrip to zero in on the fermentation temp:
http://www.tequipment.net/GeneralMDP300PP.htmlI figure if the LCD tempstrip and the digital thermometer agree, then we're in business. I heard John Maier say he ferments at 60F with Pacman (and has gone way, way lower on occasion) -- so I'm going to try something like that for my next brew -- a black IPA. (I suspect the shape of the fermenter has a lot to do with it, too -- conical versus better bottle (which I'm using) -- but I have no good way to temp control my minibrew 7 gallon conical. It may be relegated to early spring/late fall brews, where the basement stays very cool and I don't have to worry about all this.)
