'Swamp Coolers' and temperature control

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as many of you know, i'm a very active member here on the HBT forums. it's one of my favorite things to do to pass the time between brews. in fact, i enjoy few things more than talking beer with everyone here. one of the more common topics i see popping up on the forums is temp control, or issues with brews due to a lack thereof. one many of these thread i notice myself and others recommending some solid ways to keep temps in check during active fermentation. in this blog entry, i will cover the importance of temp control, my experiences with controlling, and not controlling temps durning fermentation, and offer a good way to cheaply and easily control fermentation temps. the 'Swamp Cooler'.

first of, i can't stress enough how important it is to control and maintain temps during active fermentation. personally, i feel it ranks right up there with pitching enough yeast and proper aeration. in fact, they're all related. it's all about providing healthy yeast with a healthy work environment. after all, the yeast are our employees, hired to make beer for us. it's our duty to give them what they need to do the job right. controlling temps is part of that duty.
i feel that most ales should be fermented at 60-75 degrees, based on yeast strain and the desired flavors in the beer you're making. the problem here is that no matter what the temps are when you pitch, fermentation is exothermic, it creates heat. so merely pitching at the right temp does little to ensure proper temps during fermentation. for this you need some sort of temp control, be it a fancy fermentation chamber, a fridge w/ a controller on it, or my method of the swamp cooler. whichever way you choose will work well if you know the proper temps for the yeast you're using.
when i first started brewing, i'd only read Papazian's book. while he covers fermentation temps, he doesn't go into much detail of the importance of good temp control or any ways to easily control temps. so, needless to say, i started fermenting beer in buckets in a closet in my from room. the ambient temps in there are around 67-70 degrees, based on season. most of my beers turned out well, as they were american style ales using yeasts like s-05. but i started to notice that my english style beers tasted funny. sort of like buttered fruit. diacetyl and excessive ester production. so i started reading and picking the brains of the more experienced members here on HBT. (thanks too all of them for helping me learn how important temps are to a beer). one of the first things i did after learning about temp control was to go out and buy an 18 gal bucket to use as a water bath. i though t i was an f'n genius, then i noticed every other home brewer figured that one out too. it still felt good as my next brew, an english bitter, was going to be fermented at the temp i chose. it turned out great. very great, actually.
so fast forward a bit and i now have a few large, round rope totes that i use for temp control. if you read my earlier blog on fermenting at cooler temps, you can see some of the ways i use it to keep a ferment nice and cool. briefly, i ferment the bulk of my ales on the cool side of the strains temp range, allowing it to warm up a bit by the end of active fermentation, then holding it there for several days to a week after FG is reached. i find this produces a nice, clean, well attenuated beer with the appropriate fermentation flavors for it's particular style. and i've found that doing this is a very easy part of brewing beer at home. i also feel my method is one of the most accessible ways to control temps and very affordable even for the most frugal of home brewers.
the 'swamp cooler'. as i find myself saying to some posters, 'no, not the type of swamp cooler you have to cool your garage or outbuilding.'. what i mean here is just a large bucket. i recommend 15+ gallons, but measure the dimensions of your fermenters and get one that suits your needs. i like the 18 gal 'rope totes' i got at Home Depot, i believe they were around $10-12. so now that you've gotten a bucket, you'll need a thermometer, i use a floating milk thermometer, some frozen plastic bottles of water and a small aquarium heater (optional). a 50w heater, preferably fully submersible variety should do the trick. PetSmart or a place like that should have them for under $20. i prefer the ones that can actually be set to a temperature over the ones that just have a dial with 'high and 'low' settings. you're an aquarium keeper like me, you probably have one or two laying around the house. it's as simple and cheap as that. now you just place your fermenter full of fermentation temp wort into the bucket, you may need a towel or something under it if the bottom of the bucket has ridges. fill the bucket to the level of the wort with water that's at your desired fermentation temp, or a degree or two lower as room temp and the yeast will probably raise it right back up. monitor the temps closely, and adjust them as needed with frozen bottles. i find that during active fermentation, one or two bottles will drop you 2-3 degrees, though that's dependent on a few factors like room temp and how active the fermentation is. i've also found that a 6.5 gal Ale Pail is great a water bath for my 3 gal carboys, although you'll need thin ice packs or something similar to cool the fermenter.
Attachment 325
one of my 'swamp coolers' this morning with my Rye P.A. reaching high krausen.
Attachment 326
ice bottles keeping it at 60 degrees.
Attachment 327
Rena 100W aquarium heater. a smaller heater will work fine, i used the ones i wasn't using in my aquariums.
Attachment 328
3 gal carboy of RIS in a water bath 6.5 gal Ale Pale. bottles won't fit in here, but thin blue cooler packs will do just fine.
i hope this is helpful to those of you who're looking into an easy way to maintain temps during fermentation. again, i can't stress enough the importance of controlled fermentation temps to the finished beer. and this is by far the cheapest, and a fairly easy way to start controlling temps today.


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glad i could help. if you have any questions about temp control, want to add to what i have here, or have an idea for an interesting write up, feel free to post a comment or PM me. some pics of how others have their swamp setups would be cool to see.
Thanks for this post. I've been trying to find a way to brew lagers to ferment properly and haven't purchased any kits due to my temps never going below 65 in my basement. Do you have to keep changing to ice bottles to maintain the 50-55 degrees that some recipes prefer to lager?
Thanks for the great post. I'm really new to all of this, but will definitely have to use a swamp cooler for my next brew as I live in Alabama (and It's May). I know I've seen those types of buckets before, but I can't seem to find anything similar at lowes. Do you happen to recall the brand? Much thanks.
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Sleephla, yeah, you'll have to keep changing bottles to maintain temps, especially with a lager. But once you get it dialed in, it's easy to maintain with a bottle (or two) here and there.
Wrangler, the brand of tote I prefer I've gotten at Home Cheapo, it's a Pioneer Plastics brand. Home Depot keeps these totes by the large outdoor trash bins. The one pictures above is a cheapie ($6) from WalMart. I found that in the home storage area. Both work great.
I got a tub a few months ago before I saw this and plan on using it soon, now that it's in the low 90's.
Note: check for leaks first. Though many of these tubs are soft plastic, they might have small leaks and the hard plastic ones can crack if dropped or mishandled. You want to check for leaks before you brew.
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Yeah, I've broken one. My son was helping me carry it outside to dump, and the lip split. I now use it to hold a keg at parties!
Wow, this is aweomse. I have been wondering how I am going to be able to maintain cooler temps so I can brew lagers, but this makes it look easy! Thanks for sharing.
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@Mangy17, I'll let TxBrew know. Only a couple are loading for me, as well. They've been having trouble with photos since the overhaul of the site. If you have any questions or wanna see the missing photos, PM me and I'll be happy to help.
I live in a very dry climate so this works well for me:
Rope Tote bucket, fill 1/3 with water, place fermenter in, direct fan straight down onto water as close as possible. I lay a box fan right on top.
I live in a split level with my lower level partially below grade and on a concrete slab.
Temp upstairs in the summer with A/C =77F
Temp of liquids sitting on downstairs concrete =72F
Temp of water in rope tote with fan =62F !!!!! Awesome!
Awesome write up. I was thinking of using this method to keep my fermentations cool during the summer. I was just wondering if you use the thermometer to tell the temperature of the "swamp Cooler" water? and how do you get a temp reading from the wort? Also how are you using the aquarium heater? is it meant to kick on if the temps drop too low? How is the aquarium heater placed in the water? sits at bottom or attaches to the side? Do you leave the heater in the whole time or only when you need to heat up the water?
Thanks for any help.