Swamp Cooler

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mdstrobe

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Quite simply, how do I build one to keep my fermentation temperature consistent?

Does anyone have an answer or a link to where this answer is?

Thanks in advance!
 

Naked_Eskimo

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My swamp cooler is a 36"x24"x24" rubbermaid (Walmart ~$7) filled one third-way up with water. Replace an a large ice pack 1-2 a day and temps are stable around 64F.
 
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mdstrobe

mdstrobe

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Here's what I got from BillyBrew.com

Fermenting your homebrew at the right temperature is one of the critical factors in making a good brew. Let the temperature get out of whack, and the yeast will punish you.

Since 95% of homebrewed beers are ales, temperature control is usually not an issue. Ales are perfectly fine fermenting at room temperature between 70-75 degrees F. It’s when you use lager yeast that things get tricky. These Eskimos like to work between 50-55F. That’s tough for a homebrewer without specialized equipment.

My latest homebrew is a Kolsch, which uses an unusual blend of ale and lager yeast (White Labs WLP080). It still requires lower temperatures, 65-70F, but that is much more manageable than 50-55F. I aimed for 63-65F because reviews said that the strain works best in that range.
Enter the Swamp Cooler

A swamp cooler is a crude fermentation chamber used to keep lower temperatures. It is usually made out of a cooler, bin, or other large container. The idea is that you put your fermenter into the container with cool water and use ice packs to maintain low temperatures.

As you can see in the picture below, my swamp cooler consisted of:

* Water filled to the beer level
* A plastic tub typically used for holding beer cans or a keg
* A t-shirt (towel can also be used)
* A combination of frozen water bottles, small ice packs (the kind used for ankle sprains), and ice filled Ziploc bags

I kept the shirt wet for the evaporative cooling effect. The picture below shows the inside of my set up:

Swamp Cooler Top View
The Results

swamp-cooler-top.jpg


The goal was to rotate the frozen objects in and out to try to maintain my temperature range between 63-65F. There were 2 main challenges with this:

1. Getting the temperature low enough
2. Consistency and preventing large fluctuations

#2 was my biggest concern. It’s often said that preventing wild temperature fluctuations is more important than the temperature itself. Making it more difficult was the fact that I was out of the house 8-9 hours per day with no Keebler Elves to manage my swamp cooler.

Here are the readings for the first 2 1/2 days. WARNING: DO NOT LET YOUR KIDS LEARN CHARTING FROM THIS P.O.S.! The time axis is not to scale and I mainly took readings on the high side. Still, it is telling…

Swamp Cooler Temperature Chart

At first I was worried that I wouldn’t be able to get the temperature low enough. 2 water bottles brought it down to 66F from room temperature (72F), but it went no lower. Frustrated, I replaced the 2 water bottles with 2 new ones and 2 Ziploc bags.

Oops! 52 degrees! At least I knew it could go low enough…

Once I got the routine down it wasn’t hard to keep the temperature between 60-65F. The beer is 1 1/2 weeks in and I’ve maintained that range the entire time. Not the ideal consistency, but acceptable.

Some notes:

* Once the temperature reached 62F it could be maintained by adding 1 frozen water bottle every 3-4 hours when it hit 65F.
* It was much easier to maintain the temperature in the evenings because I was around the house and could use the small ice packs for minor adjustments. It was overnight and during the day that were trickier, and when I got more fluctuation.
* Many homebrewers recommend aiming a fan directly at the carboy to help with cooling. I tried this and didn’t see any difference. I think it was because my carboy was mostly covered by the tub and only a small bit of air hit the top of it.

Final Notes

If you (or someone else) can be around enough to rotate ice packs, then this is a great way to do cooler fermentations. Just be forewarned that anything in the 50-60F range will require very close attention. I actually think this tub type arrangement is a better strategy for fermenting ales between 65-70F. This is much easier to maintain and will yield cleaner tasting beer (less esters) than one fermented at room temperature or above.

Will I do it again? Damn right.

But I have big plans for upgrading the next one. (Hint: it involves a cooler)

Stay tuned for Swamp Cooler – Part Duex.

Have you tried anything like a swamp cooler to lower your fermentation temperature?
 

arturo7

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tub + water + t-shirt or towel over the fermenter = your basic swamp cooler

if you need more cooling add a fan

still more cooling add ice
 

Beer_Guy

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I too use a cold water bath technique to maintain early temps.

However, I use a large insulated cooler and it holds the temps very well. I found I only needed to add ice every 6-8 hours during high Krausen to maintain 62-64*. By adding in about 12 or so ice cubes, the water temp drops by 2.5*s in my case. When the water level gets too high I just drain off a little bit.

For large buckets or Carboys I would suggest you could get the largest storage container you can. Insulate it with spray foam or something. It will then better resist the temp rise caused from high Krausen longer. Plus the larger volume of cooling water will help too.

Oh and getting a remote digital thermometer to monitor water temp without opening the cooler helps.
 

Revvy

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Mine is ever so complex...do you think you still need a link, or schematics? :D

fermenting.jpg


brewcloset1.jpg


The most dificult part is jamming enough different soda bottles in my freezer to freeze them. ;)
 

Beer_Guy

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WHAT????:eek:

Revvy uses a MrBeer Fermenter?

Oh the humanity!!!!

(Just kidding. I use MrBeer HME and UME in some of my brews. Way quicker on those short brew days.);)
 

Revvy

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WHAT????:eek:

Revvy uses a MrBeer Fermenter?

Oh the humanity!!!!

(Just kidding. I use MrBeer HME and UME in some of my brews. Way quicker on those short brew days.);)

If you've read any of my experimental 2.5 gallon batch answers you will see that I recommend the little brown jug as a great fermenter for small batch brewing. It is a great way to even lager in a fridge without haveing to take out shelves.
 

Beer_Guy

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I agree, and if I had one, I WOULD use it. For now I use 1 gallon Jugs for my test batches, but the MB keg would fit in the fridge better.

Plus, like I said, "Just kidding" with you.
 

Strangebird

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Are you guys doing AG with your swamp coolers? Just a day or two ago some folks on here were saying don't bother going AG until you have "real" cooling (aka dedicated fridge with temp control). I was thinking of going AG soon and just have something similar to what's in the photos above.
 

cenla

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Are you guys doing AG with your swamp coolers? Just a day or two ago some folks on here were saying don't bother going AG until you have "real" cooling (aka dedicated fridge with temp control). I was thinking of going AG soon and just have something similar to what's in the photos above.

AG or extract does not affect whether to use a swamp cooler or not.
 

JonK331

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Are you guys doing AG with your swamp coolers? Just a day or two ago some folks on here were saying don't bother going AG until you have "real" cooling (aka dedicated fridge with temp control). I was thinking of going AG soon and just have something similar to what's in the photos above.

Yes I do all grain with a swamp cooler. One of the posters on that thread obviously has a lot of space and a lot of money. A fridge is nice but a swamp cooler works very well. I would highly recommend buying a cube cooler that fits a carboy. It holds the temp much better and there's no condensation to run on the floor. It also can be used as a keg tub and to crash cool.
 

portalgod

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AG or extract does not affect whether to use a swamp cooler or not.

Agree. Use it unless you know your ferm temps stay within range and are stable over the ferm time.

I used a swamp cooler quite a bit earlier this year. My problem was that I travel a lot for my company, so I had to build a collar for a mini-fridge becuase I wasn't around to rotate ice in and out. Aside for being out of the house so much, the swamp cooler worked great to keep temps within desired ranges. It does take some practice to figure out how much ice, and the frequency of rotation, you need in your particular swamp cooler application. Depends on how much water you have in the cooler and the water temp, your ambient air temps, how frequently you rotate ice packs, and how vigorous your fermentation is.

Note that I had to rotate ice packs more frequently during the first few days of primary fermenation. Those days are much more rigorous and more exothermic reactions are occuring. Hence the need for more ice to keep temps down. After fermenation slowed, and during secondary fermentation (optional step), I was able to let it ride longer without swapping out ice packs.
 

Strangebird

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Pooh poohing a swamp cooler as a method of temp control for AG didn't make a whole lot of sense to me as long as you're successfully keeping temps in the correct range.
 
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mdstrobe

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Usually I just use the thermometer sticker I have attached to my carboy. I just finished making my swamp cooler and it works great. I basically used a plastic tub that I got from Walmart and monitored the temp on the side of the fermenter.
 

krisagon

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What if I want to boost the temp by like 3 degrees or so?

My carboy with WLP300 is at 65, and I would like to crank it up to like 68 or so to get some banana goodness.
 

Yooper

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Are you guys doing AG with your swamp coolers? Just a day or two ago some folks on here were saying don't bother going AG until you have "real" cooling (aka dedicated fridge with temp control). I was thinking of going AG soon and just have something similar to what's in the photos above.

I still don't have a dedicated fermentation chamber. Just my basement, and a cooler. Here's a picture:
4189-DSCF0002.JPG


I use a water bath up to the level of the beer, and frozen water bottles as needed. I float a thermometer in there, and I can even lager in it just like that! In the winter, I use an aquarium heater to bring the temperature UP in the water bath if needed.

I took off the original lid (and saved it, so I can still use it as a cooler) and made a new more insulated lid out of a sheet of foam insulation. It's four layers of insulation, with the hole cut out for the airlock.
 

Beer_Guy

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Are you guys monitoring the fluid temp in the cooler or the temp of the beer in the fermenter?
I had 3 one gallon jugs in my cooler with the water level 1/2 inch below the wort level. During high Krausen I checked the temp in the jugs and it was within a degree of the water temp. It seems that glass conducts the temps very efficiently when liquid is on both sides. Air maybe not so good, but water works great.

Note: these were one gallon jugs and a larger fermenter might be different due to the volume of wort. (Ok, I am not sure when the wort becomes beer, so I’m guessing since it has fermented a little, it may be technically beer. Just really weak sweet beer.)
 

JonK331

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Are you guys monitoring the fluid temp in the cooler or the temp of the beer in the fermenter?

I use a floating dairy thermometer in the cooler water. Obviously the beer inside the fermenter takes a little while to equalize with the temp of the water but the same issue occurs in a fridge.
 

Dale_3rd

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I have to say, I tried the rope handle 18 gallon tub filled with water (~$7) and just placed the fermenting bucket in it and filled to about the same level with water as wort and have been alternating frozen bottles of water and freezer packs for a few days. It works quite well; crude but effective!

Wort temp when I pitched the yeast around 3pm Sunday was 80, by the evening (8ish) it was down to mid 70's, the next morning 68-70 and today at lunch I'd added to much cooling and the wort itself was 58F. As a noob I'd recommend this method for anyone trying to get the temps down or even trying to do some lagering.

knowing how well this works, I'll be doing a 10 gallon batch of Saccharomyces Irish Red with a lager yeast very soon and expanding this method to a larger Rubbermaid bin to house 2 fermenting buckets.
 

Mase

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This seems like a great idea. I have an old tote that I can't find the lid to just laying around so it should be perfect. My question is though, if I'm using a stick on thermometer on my bucket/ carboy putting a wet shirt around it will ruin it and I'd also not be able to monitor the Fermenter temp. How do you all get around that?
 

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This seems like a great idea. I have an old tote that I can't find the lid to just laying around so it should be perfect. My question is though, if I'm using a stick on thermometer on my bucket/ carboy putting a wet shirt around it will ruin it and I'd also not be able to monitor the Fermenter temp. How do you all get around that?

This is a little bit of an older thread, but I was wondering this same thing. I'm looking to use the swamp cooler method, but how do you easily monitor the actual fermentation temperature if you have a wet t-shirt wrapped around it, and high water levels, which can ruin the temp stickers?
 

DonutMuncher

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How does it ruin it? Or do you mean it just renders it inaccurate while the outside level of the water is touching it?

I've read a few reviews/comments from people saying that when they mounted temp stickers on the outside of their carboys/buckets, some of the sticker faded away or ceased to work if water came into contact with it. Is that a common problem?

I suppose I could put clear tape over it to protect it from water damage if it's an issue.. but I'm not sure if that would affect the temp reading.
 

bleme

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I was seeing some mold growth in my swamp cooler. It was outside the fermentor, but still not pleasant. I started dumping my old Star San in to top off the water and haven't had a problem since.
 

ajzimme

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Is it detrimental for it to get so cold? Below 50?

I mean, I read that the yeast as a worst case scenario would go to sleep. But when the temp goes up again it would be in your range.

So I guess following that logic you could fill it with ice and by the time you get home you should be in the right range.

I am probably totally wrong though, I'm just guessing.
 

metanoia

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Is it detrimental for it to get so cold? Below 50?

I mean, I read that the yeast as a worst case scenario would go to sleep. But when the temp goes up again it would be in your range.

So I guess following that logic you could fill it with ice and by the time you get home you should be in the right range.

I am probably totally wrong though, I'm just guessing.

It's not the end of the world for the yeast if that happens once or twice, but constant and large temperature shifts for the yeast everyday is not the ideal environment for them.
 
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