Immersion Fermentation Temp Control

I am noodling on building a fermentation temperature control systems that is an alternative to a chest freezer. Here is what I have in mind:

Use a large Rubbermaid trashcan as an immersion chamber. I would create an immersion chiller with copper coils that will sit inside the trashcan (along the outer edge). My fermenter would sit in the can and I would fill it with water up to the level of the liquid in the fermenter.

Separately, I would use an ice chest filled with ice water (I'm thinking of using large water bottles frozen as the cooling agent for now). The water in there will be connected to an aquarium pump and then to the immersion chiller. I would use a temp controller (with a probe in the water bath in the trashcan) to kick the pump on and offer to monitor the temp.

The advantages of this method are: it will be cheaper than getting a chest freezer, I can theoretically create multiple immersion chambers that can be easily set at different temperatures, SWMBO will not really see this as me buying another damn fridge/freezer (beyond my kegorator).

Do others think this will work well? If so, what do people suggest for the pump and controller? I've heard people refer to the STC-1000, but will that end up that much cheaper than a Johnson Controller (non-digital)?

I dont see why it wouldnt work, although i dont know how efficient it will be.

If you do it, definately get a STC1000. For about $40 you can have it up and functioning as a DIY, but its very basic wiring if you can follow the diagrams on what goes where.

The johnson is going to be atleast twice that much and only a single stage(can only cool) where as the STC1000 can do run both a hot and cold outlet.

The first thing I see that would be an issue is you are trying to cool ALOT of liquid with just an ice chest full (wort+fermentation heat+water around fermenter)... I bet you would run through Ice very quickly trying too cool all that. What about wrapping the chiller coils tightly around the fermenter (since it sounds like you are fabricating them) and insulating around that? keeps you from having to cool the excess water.

Edit:.... had to fix a horrible spelling issue that was nagging me.

Would it not be easier and way cheaper to just buy a few rubbermaid buckets and used frozen gallon jugs to regulate temps? I'd imagine this thing would loose cold just as fast as it would recirculate it meaning it would practically constantly be running. With your model, you've got copper, pump, hoses, rubbermaid, wiring, and controller to buy. You could use that money better elsewhere I think.

Your idea will still work though :fro:

FuzzeWuzze said:

I dont see why it wouldnt work, although i dont know how efficient it will be.

If you do it, definately get a STC1000. For about $40 you can have it up and functioning as a DIY, but its very basic wiring if you can follow the diagrams on what goes where.

The johnson is going to be atleast twice that much and only a single stage(can only cool) where as the STC1000 can do run both a hot and cold outlet.

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Thanks. I'm hoping it will be efficient because the ambient air temp is pretty close to ale ferment temps (my basement is almost always below 70 degrees). Given the large thermal mass of the water, I'm thinking the system will mainly need to work to counteract the heat created by the yeast during the ferment. It's really just a swamp cooler with the advantage that I can more precisely control the temp.

Interesting idea. It will work just a different style cooling jacket.

dieden187 said:

The first thing I see that would be an issue is you are trying to cool ALOT of liquid with just an ice chest full (wort+fermentation heat+water around fermenter)... I bet you would run through Ice very quickly trying too cool all that. What about wrapping the chiller coils tightly around the fermenter (since it sounds like you are fabricating them) and insulating around that? keeps you from having to cool the excess water.

Edit:.... had to fix a horrible spelling issue that was nagging me.

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This is the only real concern I have. I would not be using this to cool the water initially. My tap water is decently cool, so worst case, the water going in to start would be close to the temp I would want to maintain during fermentation temp. The system would be used to offset the energy from the yeast.

rklinck said:

The system would be used to offset the energy from the yeast.

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I really think a couple frozen 1 gallon jugs could solve this problem and be much cheaper.

If ambient is that close to your target temp, you should be good. Having that much water around it will keep it very close to ambient. Sounds like a good plan.

this system will work fine. I would use insulated tubs (old ice chests) whererever possible, to get the most efficiency. A rubbermaid trash can is going to form condensate and lose some of the cool you are trying to achieve.

If your kegorator is nearby and is not packed full of beer, you could use the refrigeration capabilities and store your 'ice water' in there, and pump over to the fermenter on demand. I do a very similar process to yours, and I can keep my fermenter in a 90F garage and maintain 65°F with 5 gallons of ice water in my kegerator. BUT my fermenter is well insulated. Instead of wrapping coils around the fermenter, I just used a new automatic transmission oil cooler and immerse that in the bath. A separate pond pump continuously running prevents cold spots in the bath.

Hang Glider said:

this system will work fine. I would use insulated tubs (old ice chests) whererever possible, to get the most efficiency. A rubbermaid trash can is going to form condensate and lose some of the cool you are trying to achieve.

If your kegorator is nearby and is not packed full of beer, you could use the refrigeration capabilities and store your 'ice water' in there, and pump over to the fermenter on demand. I do a very similar process to yours, and I can keep my fermenter in a 90F garage and maintain 65°F with 5 gallons of ice water in my kegerator. BUT my fermenter is well insulated. Instead of wrapping coils around the fermenter, I just used a new automatic transmission oil cooler and immerse that in the bath. A separate pond pump continuously running prevents cold spots in the bath.

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Thanks. I love this forum because folks are so willing to help out. Using the kegorator is an interesting idea, but I am not sure if the wife will go for it. It is in the finished part of our basement. Although it shares a wall with the large closet I have been using for fermenting, I'm not sure my wife would take too kindly to me drilling holes in the wall to run the cooling lines through. Also, I'm thinking I can win brownie points by moving the fermenters to our unfinished utility room (and out of the closet). Aside from getting the fermenters our of a closet she uses, this will force me to keep the utility room clean so that I can actually get to the fermenters.

Luckily, someone posted something in another thread that suggested using an office water cooler for refrigeration. I may consider that route if I can find one for cheap on CL.

You could do it like this. With a 100w mini-fridge it’ll pull 17C (30F), that is to say I’m fermenting one at 17C (62F) and secondary at 20C (68F). Ambient is 27C (80F).

It was underpowered until I stuck the evaporator coil in the bucket. Cooling the water bucket with air it wouldn’t quite hold one fermentor at 17C (68F). I had to supplement it with 1 or 2 half-liter frozen water bottles twice a day in the bucket.

When I was using an Igloo cooler as the bucket (no fridge) it was more like 8 half-liter bottles/12h with both fermentors running as above.

Iodophor or IO Star makes a good disinfectant. I usually change the water every few weeks.

Hey! You been snoopin' around my basement? :cross:

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AnOldUR said:

Hey! You been snoopin' around my basement? :cross: .

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Ooohhh, I may have to steal that idea!!!

This is my setup, it's very similar to what you're trying to accomplish, just a little smaller scale. My 10 gal mash tun holds a 3 gal better bottle and a small pond pump. The 2nd rectangular cooler holds my chiller and frozen water bottles. The lids are just 2 pieces of 1" foam glued together and the lower layer of foam sits inside the top of the coolers with a snug fit. That way I didn't have to cut or drill the original lids. It's powered by an stc-1000. Plenty efficient for me. Just need to swap out the frozen water bottles every couple days.

Hey! You been snoopin' around my basement?

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What’s a basement? In Texas we don’t have basements, we have swimming pools. I don’t know why. I have theories.

Uncanny. I just noted that you bent the evaporator panel into the bucket. Are we brilliant or what? I asked an Electrical Engineer about it before I tried it, he said don’t bother. I guess I needed an ME.

All righty then . . . check out my controller. The fermenters are on the sides, top cold, bottom warm. The middle controller is pigtailed to the fridge and the middle outlet is unswitched.

It’s actually weird that I don’t have to mess with it anymore. I just drink beer, watch TV and listen to the relays click. Then again it’s kinda cool.

Jerf I notice you’re using a 20 amp outlet with 10 amp relays. Try to avoid the temptation to plug in a welder or something.

Wynne-R said:

Jerf I notice you’re using a 20 amp outlet with 10 amp relays. Try to avoid the temptation to plug in a welder or something.

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Ya I realize that, it's just what I had laying around. It's not the best match for the relays, but it does work and this will only be used for simple temp control purposes. It sure is awesome not having to worry about fermentation temperature, and produces much better beer! :rockin:

Wynne-R said:

Uncanny. I just noted that you bent the condenser panel into the bucket. Are we brilliant or what?

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Not sure about brilliant. Mine was a slow, ugly process. Lots of versions before coming up with the bucket, bend down.

Now that most of the bugs are worked out, it works really well. I like your three temperature controls. I'm getting by with the thermostat in the fridge and a single Ranco to control the pump that holds the bath temperature..

Update:

After seeing AnOldUR had insulated everything, including the bucket in the fridge (?) I decided I should cover the tubs. Even though I used to derive hours of entertainment watching the fermentation, the yeast seem to enjoy partying in the dark.

Uncovered it was about all I could do to pull 17C, now I’m pulling 22C with relative ease. I decided to cold crash the secondary so I have one at 15C and the primary at 16.4C, in 27C ambient. In US customary that’s 59F, and 61.5F in a warm 80.6 apartment. That’s with the compressor running about 2/3 of the time.

The moral of this story is that it doesn’t do much good to insulate the walls if you don’t have a roof.

I have the Basic Brewing Videos from Basic Brewing Radio. Jim Spencer did the same thing that you are describing and he called it his Low Tech Lagering System. He uses it lagering beers in his basement in Arkansas. I think that it should work, and I have begun a system just like it.

Mark