Partial DIY Fermentation Temp Control Using Cool Zone Cooling Jacket

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Woodbrews

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I wanted to document my experience building a fermentation temperature control system based on Gotta-Brew's Cool Zone cooling jacket. I finally finished it up last night it works, so it's time to post!

Plan
The system is based on a cooling jacket around my carboy. Gotta-Brew's Cool Zone system includes a ready-made cooling jacket and insulated cover that fits my 6.5 gallon carboy nicely. Next to the carboy is a round Igloo cooler filled with ice water. The cooler houses a small submersible pump. The pump is plugged into the STC-1000 temperature controller. Inside the cooling jacket, taped to the carboy, is a heatwrap, which also is plugged into the temp controller. When cooling, the pump will circulate cold water through the carboy jacket. When heating, the heatwrap will activate and surround the carboy with heat. Temperature is monitored by the STC-1000 sensor inside a stainless steel thermowell placed inside the carboy. It measures the temperature of the fermenting beer itself rather than the ambient temperature.

One initial decision was whether to use a standard cooler for the cooling water or use my kegerator. Using the kegerator would require an additional hole through the side and a long-ish run of tubing that would need to be insulated. A separate cooler, in contrast, would require frequently replenishing the ice inside to keep the water cold. The separate cooler likely would be more compact, because it could be stored on the shelf next to the fermenter and the tubing would only need to span 1 to 2 feet instead of nearly 10 feet.

With only one batch fermenting at a time, I decided to start with the cooler and move to using the refrigerator if there becomes a need to ferment multiple batches at a time.

Components
- Cool Zone cooling jacket (purchased)
- Carboy thermowell (DIY) (completed)
- STC-1000 controller (DIY) (completed)
- Submersible pond pump (Amazon) (purchased)
- 1/2” ID tubing (no need to be food safe) (purchased)
- tubing quick connects (included with Cool Zone jacket)
- 5 gallon Igloo cooler (purchased)

Progress
I received the CoolZone jacket and 25 watt heater as a birthday gift from my lovely SWMBO. I also purchased a small submersible pond pump, some 1/2” ID tubing, and the parts to build a DIY temperature controller based on the STC-1000 unit.

I built the thermowell using a plain stainless steel thermowell from Brewhardware. I coated the STC-1000 sensor with thermal paste and slid it to the bottom of the thermowell. I then covered the top of the thermowell with shrinkwrap to make a splashproof seal around sensor wire.

I completed the STC-1000 controller last night and was gratified to have it work the first time I plugged it in. I guess I’ve learned something from my EE dad! After reading the instructions, I programmed it to maintain 19.5 C (~ 67 F). I drilled a second hole in my spare stopper and sanitized it and the thermowell. When placed in my fermenting beer, it read 22 C (~ 70 F). After a 3 minute delay (the default setting on the STC-1000), the pump came on and began pumping cold water through the cooling jacket. Because the pump is inside the cooler with the lid shut, I could barely hear it when it came on. But you could see the cold water moving through the hoses.

After a few minutes, the temp dropped 0.1 C, and a few minutes later, 0.2 C. I would expect the temperature changes to be rather slow, given the thermal mass of 5 gallons of fermenting beer. I checked it this morning and it was a steady 19.6 C, within the 0.5 hysteresis setting of my 19.5 target temperature. All of the ice in the cooler was melted, so I added a frozen 1/2 gallon milk carton. It will take some time to determine how often ice needs to be replenished in the cooler. It will also require some experimentation to see whether the cooling jacket can bring the carboy temp down to cold crashing or lagering ranges.

Future Improvements
Future improvements include flashing the firmware on the STC-1000 to allow for setting and reading temps in F, and to program steps at different set points, set forth in this great thread. At $20 for a STC-1000, the risk is minimal.

Another improvement would be to move the pump and water bucket into my kegerator. There are three major hurdles to overcome: (1) distance between carboy and kegerator (placing it adjacent is not possible, because my wine refrigerator is next the kegerator); (2) drilling another hole in the refrigerator; and (3) finding room in the refrigerator, which is used for storing food as well as being a kegerator.

This was a fun project, and it was good to tackle the "cold side" of my process after building my electric BIAB kit (see build thread here).

photo 2.jpg
 
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Woodbrews

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Here's a pic of the system in action.ImageUploadedByHome Brew1394847917.823644.jpg


Sent from my iPad using Home Brew
 

IL1kebeer

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What would be inside of the fridge or kegerator if that route were to be taken with this system? A bucket or similar vessel filled with water that gets recirculated?

Also, what's the gph of the submersible pump that you are using?
 
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Woodbrews

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What would be inside of the fridge or kegerator if that route were to be taken with this system? A bucket or similar vessel filled with water that gets recirculated?

Also, what's the gph of the submersible pump that you are using?
Just a small bucket of water - enough to hold 2.5 to 3 gallons and the small pump. I am using an EcoPlus 396gph pump ordered from Amazon. It works perfectly for my setup and doubtless would handle more than one cooling jacket. At $21 the price was right.

I realize that I could have found a dorm fridge on Craigslist for less than my total investment in this project (approx. $200). But this setup takes up less space and can be stored away. I also can use the pump and cooler as a pre-chiller for my IC, so I'm getting extra value out of that investment.
 
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Woodbrews

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It's time to cold-crash my beer, so I'm trying a little experiment today -- I added fresh ice water and 6 frozen water bottles to the cooler this morning and then set the temp down to 3 C (~ 37F). I'm curious as to how far down it will go. Unfortunately I don't have an independent way to log temperatures, so I'll just have to observe. Should be interesting.
 

WayFrae

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Nice! I like your set up. I have been considering getting the cool zone myself so I am eager to see if you can cold crash with it. I found a water cooler on amazon from the Coleman Xtreme series. They advertise that it will hold ice for 5 days, obviously you wouldn't get that with it recirculating but it would help you not lose as much ice while the pump is not running.
 
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Woodbrews

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So how did the cool zone work for cold crashing?
I wasn't there to babysit it, so I don't know how low it went. It was in the low 50sF when I got home from work and all of the water bottles were thawed. My guess is that you'd need to change out the bottles every few hours to keep the temps low. If you feed it with cold water from a refrigerator, instead of from a separate igloo cooler, it likely would get down to close to lagering temps. Ultimately, for this batch, I decided to rack it to a second carboy that would fit inside my refrigerator. I'll cold crash it for two days and then rack it to my keg.
 
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Woodbrews

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Just an update on this project (sorry, no pics yet). I went ahead and cut a hole in the side of my refrigerator and put a water reservoir and pump inside. With constant 40 degree water I was able to use the Cool Zone to reduce my wort from 89 degrees to pitching temp (70F) in a few hours (I actually did it overnight, so I don't know precisely how long it took) and then hold it at a constant 68F for two weeks. It's nice to be able to "set and forget" my fermentation process. Future upgrades include flashing the firmware on the STC-1000 so it will read in Fahrenheit and can handle temperature ramps.
 

scutiger

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I've just got my cool zone in the mail this morning, the complete setup minus the heater and cooler. I went ahead and bought everything from them cause it was just more convenient.

I'm glad it's worked out for you cause I haven't been able to find much about it other than what they claim on their website. I'll be putting a hole in my mini-fridge and keeping a 4 gallon reservoir to hold the recirculating water so I'm thinking after seeing your results I'll be set!
 

Tropidolaemus

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Thanks for posting those! I have been trying to figure out what will work best for me since my chest freezer died a few months ago. This seems like a great fit for my space and cooling needs. I too couldn't find much other than their website testimonials. After seeing your results I think I have a winner. The one thing no one really talks about is the cost savings in running the water pump as opposed to the cost of running the freezer. That's a big bonus for me. Using my kegerator as the cooling source is using 1 less major appliance (the freezer) and pulling double duty with the one I'm already running regardless. Seems like a win win to me!
 

Boydric

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What if you ran the water from the fermenter to a bucket or heat exchanger in the fridge then to the cooler full of ice prior to the fermenter? You might get the ice to last longer by pulling some of the heat out and get the extra cooling from the ice. Just a thought after a few beers.
 
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Woodbrews

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Has anyone considered using a PC cooler radiator in a fridge/freezer instead of a large bucket of water?
Would the radiator just take the place of the reservoir? Or would there still be a small reservoir for the pump to sit in, with the water routed through the radiator and then into the CoolZone (with the radiator mounted inside the refrigerator)?
 
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AutoDog

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Would the radiator just take the place of the reservoir? Or would there still be a small reservoir for the pump to sit in, with the water routed through the radiator and then into the CoolZone (with the radiator mounted inside the refrigerator)?
My thought was to replace the reservoir entirely with a smaller radiator inside the fridge/freezer. This is certainly much more space-efficient. If the radiator has better thermal transfer characteristics than a bucket or corny keg, then perhaps it would work despite the smaller size...?
 
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Woodbrews

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I agree, it would be much more space efficient. I guess it would be a closed loop? You'd need a different pump, because the ones used with a reservoir system are pond pumps and must be fully or partially submerged to work. I've never built a water-cooled PC, but perhaps you could use a pump from such a system. It might be worth a try . . .
 

AutoDog

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Yes, I'd agree: definitely a closed-loop system as the submersible pump wouldn't work without a reservoir. There are quite a few options for inline pumps for liquid-cooled PC systems.
 
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Woodbrews

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You'd need a way to disconnect the Cool Zone jacket from the system without losing all of your coolant. Do PC cooling systems have any kind of disconnects that shut off flow when disconnected?
 

dmcman73

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Not the cheapest route up front, but you'll save on cutting up a good fridge and also on electric by using a water chiller they use in aquariums: http://www.amazon.com/dp/B0048IVBT4/?tag=skimlinks_replacement-20

I use this to temp control my stainless steel conical with an internal stainless steel coil. Since the water flows over the cold coils in the unit then flows out the output of the chiller, the water is chilled faster rather than a bucket in a fridge/freezer being chilled ambient.
 
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Woodbrews

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Not the cheapest route up front, but you'll save on cutting up a good fridge and also on electric by using a water chiller they use in aquariums: http://www.amazon.com/dp/B0048IVBT4/?tag=skimlinks_replacement-20

I use this to temp control my stainless steel conical with an internal stainless steel coil. Since the water flows over the cold coils in the unit then flows out the output of the chiller, the water is chilled faster rather than a bucket in a fridge/freezer being chilled ambient.
Thanks for the link. I had not known of aquarium chillers being used for fermentation, but it does make sense. When you use this for your conical, do you use the temp controller on the unit, or a separate temp controller linked to the conical? I guess you'd want both the cooling unit and the pump to come on when cooling, right? Thanks.
 
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dmcman73

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Thanks for the link. I had not known of aquarium chillers being used for fermentation, but it does make sense. When you use this for your conical, do you use the temp controller on the unit, or a separate temp controller linked to the conical? I guess you'd want both the cooling unit and the pump to come on when cooling, right? Thanks.
I just described this setup in another post: https://www.homebrewtalk.com/f11/ssbrewtech-ferment-temp-control-484586/index2.html

Look at post #17 for a picture of my setup and post #19 for how I set it up.

Basically this units are built to have water constantly ran through them. They have their own internal temp sensors that monitor the water that flows through it. If the water temp drops below a specified temp that you set it at, the compressor will kick in and start chilling the water.

The conical I have from SSbrewtech has a specifically made cover with an immersion style chiller built into it. The temp controller for the fermentor chiller monitors the wort, if it drops, a pump that it came with kicks on and pushes water though the input port of water chiller. Once the chiller senses warmer water, the compressor kicks on and starts chilling the water and chilled water is pushed out through the chillers output port which then goes into one side of the fermenter chilling coil. The other end of the fermentor shilling coil goes back into a cooler where the pump is in.

As I explained in post #19, you could get a bigger cooler, run a pump to pump water through the chiller 24/7 to keep the water in the cooler at a certain temp and then attach multiple fermentors to the cooler. The water shiller I have is rated to chill up to 105 gallons of water.

EDIT: So the short answer to your question, I have two separate temp controllers, one for the pump to pump water through the chiller and ferm chiller coils when needed and the other one is built into the water chiller to monitor when the compressor needs to kick in. I have the temp on the water chiller set to 65 degrees to keep my ales at 71-72 degrees. It will kick on for about 2 minutes then kick off when it needs to chill. When I first hooked it up, it took about 8-10 minutes to drop the temp from about ~78 degrees to 72 degrees.
 

AutoDog

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Not the cheapest route up front, but you'll save on cutting up a good fridge and also on electric by using a water chiller they use in aquariums: http://www.amazon.com/dp/B0048IVBT4/?tag=skimlinks_replacement-20

I use this to temp control my stainless steel conical with an internal stainless steel coil. Since the water flows over the cold coils in the unit then flows out the output of the chiller, the water is chilled faster rather than a bucket in a fridge/freezer being chilled ambient.
Very interesting... I'd looked into this earlier but couldn't swallow the price, but if you could get a deal, it's looks pretty slick.

Have you tried cold-crashing your fermentor with this?

-AD
 
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dmcman73

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Very interesting... I'd looked into this earlier but couldn't swallow the price, but if you could get a deal, it's looks pretty slick.

Have you tried cold-crashing your fermentor with this?

-AD
Not yet, I just got it and I'm using it on a Pumpkin Ale I just brewed a few weeks ago, I have another 3 weeks left, as soon as it's done fermenting, I'll try cold crashing.
 
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Woodbrews

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Not the cheapest route up front, but you'll save on cutting up a good fridge and also on electric by using a water chiller they use in aquariums: http://www.amazon.com/dp/B0048IVBT4/?tag=skimlinks_replacement-20

I use this to temp control my stainless steel conical with an internal stainless steel coil. Since the water flows over the cold coils in the unit then flows out the output of the chiller, the water is chilled faster rather than a bucket in a fridge/freezer being chilled ambient.
Thanks for the explanation and for the link to your other thread. I may consider an aquarium chiller for the future. The only way I could justify the up-front expenditure is to leverage it to cool multiple fermenters. I do like the fact that it would work with either a Cool Zone jacket and a conical with an internal stainless coil. When running multiple fermenters, I think you'd want a separate temperature controller for each, with the cooling control tied to the circulation pump. The only hitch is that you might need two circulation pumps, one for each fermenter, but since the coolant loop is a closed circuit, I'm not sure how it would work.
 
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dmcman73

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Thanks for the explanation and for the link to your other thread. I may consider an aquarium chiller for the future. The only way I could justify the up-front expenditure is to leverage it to cool multiple fermenters. I do like the fact that it would work with either a Cool Zone jacket and a conical with an internal stainless coil. When running multiple fermenters, I think you'd want a separate temperature controller for each, with the cooling control tied to the circulation pump. The only hitch is that you might need two circulation pumps, one for each fermenter, but since the coolant loop is a closed circuit, I'm not sure how it would work.
For multiples, I would hook up one primary pump that would circulate the water through the chiller and back into the cooler continuously to keep the water cold in a very large cooler. Then I would have separate pumps for each fermenter in the cooler that only went on when the temp controller for that fermenter called for cold water. If your good with electronics, you could look in the DIY section here and look up temp controllers using a Raspberry PI PC controlling relays to each pump.

Or if you really want to get fancy you could use zone valves from in-ground sprinklers attached to a manifold going to one pump. Each valve would be hooked up to each fermenter and would get turned on when needed.
 
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Woodbrews

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My eventual goal is for multiples. I like the idea of a single cold water reservoir and pump with a manifold and sprinkler zone valves and a logic controller. This would be very similar to the systems discussed in this thread. The sprinkler zone valves likely would be cheaper than the 1/2" electronic valves used in the glycol chilled plastic conical project.
 

smugslug

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Does anyone know if this thing is capable of lagering? I'm guessing with an ice chest it'd be difficult but a fridge? And with what size of reservoir?
Thanks!
 

cianclarke

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^ Indeed this is what I really want to know. I'm debating trying to design a custom water reservoir to fit in the dead space at the back of my kegerator.
Would love to know a little more on how big a reservoir needs to be, and how cool it can bring things
 

Rivenin

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i'd be guessing glycol would be best for that as (i'm guessing) water would be pretty much frozen up in the fridge trying to keep up with below 40* cooling needs, unless the fermenter was well sealed? but if you have a mini freezer/fridge and glycol i could see it working, just insulate everything :)
 
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Woodbrews

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I'd like to look into glycol as well, since I've had my water reservoir freeze up in my kegerator. Although the my refrigerator's internal thermostat is set to 43F or so, it doesn't really regulate the temperature very well and sometimes it gets way too cold.

With glycol, it may be possible to use a small freezer, instead of a refrigerator or insulated cooler, to house the reservoir. Glycol will handle much colder temperatures without freezing up, so you can bring the coolant temperature down much lower than you could with just water. You'd need to investigate whether the pump will work with glycol and at such low temperatures; if not, then one option might to use an inline pump housed outside of the freezer.

Does anyone know of any sources for propylene glycol? Is it necessary to use food grade propylene glycol?
 

dmcman73

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I'd like to look into glycol as well, since I've had my water reservoir freeze up in my kegerator. Although the my refrigerator's internal thermostat is set to 43F or so, it doesn't really regulate the temperature very well and sometimes it gets way too cold.

With glycol, it may be possible to use a small freezer, instead of a refrigerator or insulated cooler, to house the reservoir. Glycol will handle much colder temperatures without freezing up, so you can bring the coolant temperature down much lower than you could with just water. You'd need to investigate whether the pump will work with glycol and at such low temperatures; if not, then one option might to use an inline pump housed outside of the freezer.

Does anyone know of any sources for propylene glycol? Is it necessary to use food grade propylene glycol?
The question is though, how fast will the freezer cool the glycol as it's being cycled through a reservoir that s just sitting in it? If you think about it, how long does it take for a bottle of water to chill once it's placed into the fridge/freezer? I could be wrong so hopefully someone on here who has or is doing it this way can chime in.

I believe it will take longer to chill "ambient" than it would if it was being chilled directly (refrigerant coils submerged into the liquid). If I remember correctly, there were a few posts on people taking apart small A/C units so that they can place the cold side coils right into the liquid to chill it faster. I wanted a cleaner look so I purchased a used aquarium chiller, same concept. Water is pumped through a reservoir that is lined with the cold side coils from the reintegration system.
 

TrickyDick

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Food grade glycol is in case the glycol gets into the beer you won't suffer the toxic effects of something that isn't safe for human consumption, such as ethylene glycol aka antifreeze. I got mine from work for free!

Air is a poor conductor of energy to chill liquids. Rather than using a freezer to chill the coolant solution consider this. You could purchase a picnic cooler (without a drain) into which you submerge the cold-side condenser coil from a small $100 window a/c unit. Get a "dumb" one and use a temp controller such as an STC 1000 to turn the AC unit on or off at your desired temp, and maybe find a way to control the hysteresis to something pretty high to keep it from cycling all the time. It'll chill the glycol in the cooler. This requires a bit of destroying a perfectly good AC unit. You'd only need a very small one to do the trick. This would be more energy efficient in the long run.

How much pressure can the cool zone jackets handle?

For the user with the stainless FTSS through the lid fermentation chiller, can you send me some detailed pics of how that mounts to both inside and outside? Seems like a TC ferrule then some MNPT threads? Is the coil itself threaded or is there a nut or piece of pipe coupler welded on? What's the spacing between the ferrule and the threads? Is there an O ring on the inside or outside of the lid? I'm in the process of contemplating switching my plastic glycol chilled conicals over to stainless and this is a stumbling block for me- how to get a sanitary connection on the inside that is also removable and airtight.


Thanks

TD
 

augiedoggy

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I use one of these cool zone jackets for my conical and it brings 10 gallons down from 76 to 66 degrees in less than an hour while uninsulated and in a 78 degree room. The only issue I have with them is for what your buying (basically a modified $20 solar shower) they are costly. and they have already gone up another $10 in price since I ordered mine. (Im cheap I guess but I always look at what im actually buying and the costs involved in production)

I have three more fermenters to control the temps on and will likely go the route of stainless coil inside or copper coils wrapped around the outside just to save some needed $$

They do work well though ... BTW I'm using a glycol chiller with mine. and much more than 8psi although I plan on that dropping very soon when my other fermenters and the solenoid valves are plumbed in to the pump/line.
 

9Dave

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I haven't seen many new forums for feedback on the Cool Zone, and a couple point to this one, so I figured I'd post here since those looking for experience with it may check here.

I've had two Cool Zones for a year and a half and have done 33 batches with them. They're great and I'd recommend them. I planned on doing a cold water chamber in my keezer but instead went with a large Xtreme Coleman cooler. It works fine for running both of them at the same time (about 1/3 full with bottles of ice). I have to change them out about every 3 days (though my house rarely gets above high 70's). I do lagers in the winter with them, though it's in my mudroom that often gets down to the 50's. Based on my experience I'm sure I could do them in the summer but I'd likely have to change the ice about once a day and I don't feel like doing that (plus I stockpile them in the winter and pull them out of cold storage as needed).

I've cold crashed once with one of them. The beer was at 66.7. The house was at 67. It took a little over 7 hours to drop to 44F.

What I like most is how good it is at holding temps in a tight range. My friend has one and keeps his beer within a fraction of a degree. I have a wider range since I don't want the heater and pump fighting each other and making me have to change the ice as often. So, for example, I'll set the Cold at 67F and the Heat at 66F and have the differential for both at 0. When the cold kicks on it'll typically drop it to 66.5-66.8F. I've never seen it drop more than 0.8F, so with this set up I'm staying less than 1F (typically within 0.2 to 0.3 change).

The only problem is you can't leave for a few days or slack off on changing the ice. On one lager I didn't change the ice in time and I woke up the next morning to a feedback loop where it was too warm so it kept pumping the water, which was now warmer than the beer. This was slowly raising the temp as the water warmed more. Luckily the timing worked out as a D-rest.

But all in all I love the system and would recommend it.
 

9Dave

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Yes, you can collapse it but it takes a little work, though just a little. It comes with a bottom and side liner that you'd want to remove. The side one velcros into place. But once you take those out I imagine you could get it to store pretty flat, which is how I believe I received it but it's been a while (and I've left them assembled ever since).
 
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