using keezer to chill my fermenters?

[Pdaigle]

Im building a keezer and I was wondering if I could use it to chill my fermenters. So basically I would have a bucket in my keezer where I would have water with pump that would run into my fermenters chill coil in which it would be triggered from my inkbird temp controller. Would that work?

cheers!

 

[EazyMcBreazy]

Ive been considering the same approach. My concern is if a submersible pump would generate heat which could compromise a cold crash. But maintaining a temp shouldnt impact too much. Havent tried yet.

 

[GoeHaarden]

There are several threads that exist regarding this same thing. I read that the problem with this approach is the greater number of temperature transfers causes inefficiency in cooling. For example, you have to cool the air -> that air cools yours fluid in the reservoir -> this fluid then cools your fermenter through recirculated heat-exchange.

In other words, this method does work and has worked for many people. It just takes a long time and a lot of energy for the air to cool the bucket inside your keezer.

But, I do not think it is the most efficient system, and I'm not sure if cold crash temperatures can be achieved easily. I'll have to find the thread, but I found another method where a guy took the cooling coils in the back of a mini-fridge and placed it directly into the reservoir which eliminates an extra transfer. More in line with a glycol chiller.

Edit: check this out https://www.homebrewtalk.com/showthread.php?t=528052

 

[Grossy]

The concept is very simple. It is my method of chilling 20 gallon brews.

The practical application is daunting, and while I love what it is I have achieved, I am not sure if it was the best approach.

My initial write up on this can be found here.

The Grossy Wort-Chiller/Fermentation Chamber 3000.
https://www.homebrewtalk.com/showthread.php?t=476429&page=3

I had to take a break from the project, but have made a lot of progress lately. And I will be posting that progress shortly.

Here is what you need to know.

This will of course depend on the size batches you do. (If under 15 gallons I would recommend not doing this and just get a freezer or refrigerator.)

OK here we go.

The bucket of water in your freezer is going to heat up, (the pump wont be why). You are transferring heat from the fermentor to your bucket. Your freezer needs to respond. But it will do so very slowly. Chest freezers are made for long and slow chilling (crazy energy efficient), an upright freezer would respond faster.

If your bucket is warming up faster than the freezer can chill, the system will fail.

I use a 100 gallon chest freezer, and I freeze 20% of it to ice. Which forms an ice torus around the top of the chest freezer. The ice acts as a thermal mass that can absorb a lot of heat, and allows the chest freezer to respond. My system works perfectly.

I have reservations that a bucket in a freezer will have the thermal mass necessary to cope.

My first attempt at this failed, because I did not make ice. In the winter time my 100 gallons of 33 degree water warmed up to 46 degrees during fermentation. Which made chilling the wort down to 67 degrees very difficult. I knew it would never work in the summer.

You must place the pipes/tubing in the middle of the bucket, ice will form and freeze your pipes if they are near the sides.
The pipes/tubing must have a very short travel out of the freezer, or they will freeze.

Ice is your friend and your enemy, it is a balancing act.

I am fermenting 20 gallons of IPA as of this write up.
The last picture shows the temperature inside the fermentation chamber (to the left), the temperature inside the fermentor (right).

 

[mongoose33]

This will of course depend on the size batches you do. (If under 15 gallons I would recommend not doing this and just get a freezer or refrigerator.)

I use a refrigerator for 5.5 gallon batches. Takes almost 24 hours to crash from about 64 degrees to 32 degrees. I measure wort temp by a probe held to the side of the fermenter with 1" foam and a bungee cord.

I have reservations that a bucket in a freezer will have the thermal mass necessary to cope.

Depends on the batch size. For 5 gallons probably can.

Ice is your friend and your enemy, it is a balancing act.

Ice is an interesting tool. Its ability to absorb heat--or to cool, same thing--comes from the phase change from ice to liquid. I think it's clever that you're partially using ice as a fermentation cooling mechanism.

 

[GoeHaarden]

The concept is very simple. It is my method of chilling 20 gallon brews.

Cool build!

But aren't you still using air to cool your fermenters, unless I'm missing something?

 

[Grossy]

Yes, I am using cool air to cool my fermentor. But that is not a very scientific way to describe what is happening.

In science there is no such thing as "Cold" things just have less heat than other things.

I am pumping the heat out of the fermentation chamber and into the chest freezer below, which them pumps that heat into the atmosphere.

1. The air in the fermentation chamber is lowered to around 50 degrees.
2. The heat from the wort is then transferred to the air in the fermentation chamber..
3. The air then transfers the heat to the water in the transmission cooler.
4. The heat in the water is then transferred to the chest freezer.
5. The chest freezer then radiates that heat into the atmosphere.

I have thought about adding a water jacket to wrap around the fermentors, but since the system is keeping the wort within 1 degree of my target temperature, I do not see a need for it.
(I live in Tucson, Arizona it hit 116 degrees today)

Now a cold water jacket wrapped around the fermentor may improve how fast the system responds to heat changes, it will not change how fast the chest freezer can pump that heat to the atmosphere.

At the end of the day, all the heat from the fermentor is transferred to the chest freezer.

If the chest freezer cannot remove the heat fast enough (or in the case of the original poster the chest freezer cannot remove the heat from the bucket fast enough) the system will fail.

 

[GoeHaarden]

Yes, I am using cool air to cool my fermentor. But that is not a very scientific way to describe what is happening.

In science there is no such thing as "Cold" things just have less heat than other things.

Ummm...that's the same thing, only in different words.
Sounds more like a lawyer.

I am pumping the heat out of the fermentation chamber and into the chest freezer below, which them pumps that heat into the atmosphere.

• The air in the fermentation chamber is lowered to around 50 degrees.
• The heat from the wort is then transferred to the air in the fermentation chamber..
• The air then transfers the heat to the water in the transmission cooler.
• The heat in the water is then transferred to the chest freezer.
• The chest freezer then radiates that heat into the atmosphere.

This seems to be a lot of heat transfers. Seems you could just pump the cold air from the freezer into the chambers and lose a couple of thermal transfers, since it is still air cooling...on the other hand, if you connect your cooling lines to a coil inside the actual fermenter then you may have better results. Kind of like a glycol chiller. This is more in line with the OP question.

 

[Grossy]

There is very little cold air in the chest freezer, its full of water.

If you decrease the amount of water/ice in the chest freezer, to increase the amount of air, you decrease the thermal mass necessary to absorb the heat from the wort.

As I said above, a cold water jacket would increase the speed at which the wort would be cooled, a coil inside the wort would also work faster. But that will make no difference on how well the chest freezer can deal with the heat. Chest freezers are made to work efficiently, not fast.

The OPs question is will it work. The weakness in the system is not how fast the wort can be cooled, it is whether the chest freezer can deal with it. My personal experience is that without ice it will not work. A bucket in a chest freezer means that the water in the bucket must be cooled by air in the chest freezer. I have reservations on how well that will work.

Glycol chillers are filled with glycol, at around 10 degrees Fahrenheit, huge difference from 33 degree water.

I suspect that the water in the bucket is going to heat up, the chest freezer will turn on and drop the temp in the freezer to around zero degrees, then a slow process of cold air trying to chill down the bucket.

(As for my system it has a duel purpose. The first 75 gallons of the 33 degree water is used for my Counter Flow Chiller to chill the wort after the boil, the second is to chill the fermentation chamber.)

 

[Grossy]

The link in post #3 above provided by GoeHaarden has a very good write-up about the difficulties of this type of system.

And I fully agree. As I said in my original post:
"The practical application is daunting, and while I love what it is I have achieved, I am not sure if it was the best approach."

It took a lot of effort, a lot of trial and error, however after all that work I managed to make a system that fit my duel purpose needs. Wort Chiller/Fermentation chiller.

The OPs goal is fermentation chiller/Kezzer.

There are some mitigating factors that could work in the OPs favor.
It will be used inside
A 5 gallon brew.

 

[jeeppilot]

I took a similar approach that has worked well. I use my old freezer that houses my serving kegs to blow cold air into the ferm chamber. A small squirrel cage fan is attached to short PVC pipe length, which is run through the sidewall of the freezer and into the chamber. My BrewPi turns the fan on and off.

View attachment ImageUploadedByHome Brew1500642174.489702.jpg

If your keezer has a collar for taps, you could run the pipe through there, eliminating any risk of ruining a new freezer. Just food for thought.