Fermentation Chamber build - Not getting cold enough

I've been working on this fermentation chamber this week for a Blonde Ale I just brewed. Due to the temp fluctuations, I moved the ale back to my swamp cooler, but I am vested in getting this changer to work.

Here is the overview of the chamber:



I added 2" foam-board insulation over the insulation you see there, but I am still having issues with the ice in the 2 liter soda bottles melting too quickly and the chamber jumping from 18-19C to 23-24C.

I spent most of last night sealing any gaps I may have between the insulation, but this morning it was at 21.5C and the bottles were cold, but still melted.



My current plan is to take a panel of insulation and cut a small square into it for the fan I made here:



However, do I need to have two fans to have a push-pull effect to circulate air? Would sealing the ice in the fridge have the effect I want in keeping the ice longer? Am I way off mark here? When I tested the fridge with the door on, it reached close to 0C easily. If installing the foam panel works, I have an idea of turning the fridge sideways so the door is facing out parallel to the face of the chamber and cutting a square in the side of the fridge for the fan. This way I can change the ice without opening the lid of the chamber itself.

Thanks in advance for any tips and suggestions.

That looks like an enormous ferm chamber for the size of the ice you are trying to cool it with, that may be a factor. Can you explain the seal you have on the top chamber door? It looks like when its closed you have wood against wood? If that is the case, that may release a lot of the cold temperature you are trying to keep inside. Having the top foamboard be flush up against the side foamboard when closed would be better, or at least having the foamboard flush up against the weather stripping you have there.

Do you have that ice in a small fridge? Does the fridge run as well?

twocent - whats the ambient temp where your chamber is sitting?

I imagine that you just don't have enough cold to suck up all the heat that's in there. It looks like a pretty big volume you got there.

How is the lid sealing to the body?

Ambient temperature is around 75 in that room. The volume is large, but I put in a divider to try and close up the space a bit.

As for the seal on the chamber door, I added weatherstripping (not in the pictures) to where the lips meet. I should probably re-cut the foam on the lid to go past the opening so the seam is covered more.

I'm planning on re-cutting foamboard for the lid so that it goes past the side. This will also help the weather stripping I added to form a better seal.

Yes, the fridge runs as well as having the ice and the fan in there.

twocent said:

Yes, the fridge runs as well as having the ice and the fan in there.

Click to expand...

So you're having this issue with the fridge running?

If the fridge is running along with that ice, I think you may have either a serious leak in the seal somewhere or there is somewhere that is not very well insulated (most likely around the seal somewhere). Not sure why a fridge by itself wouldn't be able to keep that chamber cool.

anonymousbrew said:

So you're having this issue with the fridge running?

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Yes, which makes me think I need to recheck all of my seals.

jglazer said:

If the fridge is running along with that ice, I think you may have either a serious leak in the seal somewhere or there is somewhere that is not very well insulated (most likely around the seal somewhere). Not sure why a fridge by itself wouldn't be able to keep that chamber cool.

Click to expand...

Yeah, I think I need to go back over all of the seals and make sure there are no leaks.

that was my thought. or you're dumping heat back into the chamber from the hot side of your fridge. How is the heat dissipating from the coils?

anonymousbrew said:

that was my thought. or you're dumping heat back into the chamber from the hot side of your fridge. How is the heat dissipating from the coils?

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How do you check that?

i mean, is the entire fridge enclosed in the chamber, or is the backside of the fridge with the coils and fins exposed to the outside.

anonymousbrew said:

i mean, is the entire fridge enclosed in the chamber, or is the backside of the fridge with the coils and fins exposed to the outside.

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Only the front half is in the chamber. the coils are out the back.

It looks like you using a refrigerator to cool down a space that is almost 10 times its size. Many dorm fridges don't do a great job of cooling down their own insides.

Frankly I think this is a non-feasible idea due to the size.

broadbill said:

It looks like you using a refrigerator to cool down a space that is almost 10 times its size. Many dorm fridges don't do a great job of cooling down their own insides.

Frankly I think this is a non-feasible idea due to the size.

Click to expand...

Would switching the fridge out for a window A/c be feasible?

Try taking some foam board cut to size and installing in the middle of the camber. In essence cutting the chamber size in half. If it cools then you have an under sized fridge. I have the same type of chamber but smaller and I have a freezer/fridge to cool thats double the size of your unit. Its been thru 100 deg weather and no problem with ALE fermentation temps holding steady and the fridge is NOT running all the time.

Magic8Ball said:

Try taking some foam board cut to size and installing in the middle of the camber. In essence cutting the chamber size in half. If it cools then you have an under sized fridge. I have the same type of chamber but smaller and I have a freezer/fridge to cool thats double the size of your unit. Its been thru 100 deg weather and no problem with ALE fermentation temps holding steady and the fridge is NOT running all the time.

Click to expand...

I actually have a thick piece of 2" insulation cutting the chamber in half it runs full height and is snug

Then you need a better fridge. Here is my build FWIW not saying its the only way to do it but its working. I have tried a window AC unit, it didnt work for me. Never kept it cold enough.
Fridge I am using http://www.walmart.com/ip/Danby-4.4-cu-ft-Refrigerator-Spotless-Steel/16621129

Magic8Ball said:

Then you need a better fridge. Here is my build FWIW not saying its the only way to do it but its working. I have tried a window AC unit, it didnt work for me. Never kept it cold enough.
Fridge I am using http://www.walmart.com/ip/Danby-4.4-cu-ft-Refrigerator-Spotless-Steel/16621129

Click to expand...

Nice. For that price, I wonder if I could use a chest freezer and cut a hole in the side for a fan

Something like this:

http://southjersey.craigslist.org/app/3895226775.html

twocent said:

Would switching the fridge out for a window A/c be feasible?

Click to expand...

I have a box that looks exactly like that, I use a small window AC unit and it works great. The AC unit only goes down to 60 degrees, so that's as cold as i can get it but it works great for ales.

The AC unit is made to cool a larger area than a mini fridge, so should work better.

Klutz said:

I have a box that looks exactly like that, I use a small window AC unit and it works great. The AC unit only goes down to 60 degrees, so that's as cold as i can get it but it works great for ales.

The AC unit is made to cool a larger area than a mini fridge, so should work better.

Click to expand...

And you're able to chill down to 60-62? I know fermenting gets a bit warmer, so I'd be happy fermenting at 65ish

twocent said:

Nice. For that price, I wonder if I could use a chest freezer and cut a hole in the side for a fan

Something like this:

http://southjersey.craigslist.org/app/3895226775.html

Click to expand...

That would work, but you would need to locate the coolant lines. Maybe just do a controler on the chest freezer? My back wouldn't like a design like that for me but maybe yours is ok with it. There are a number of builds with window ac units. Just stay away from ones with a digital controler built in. I could never figure a way to bypass it. Drove me nuts.. looks like this:

twocent said:

And you're able to chill down to 60-62? I know fermenting gets a bit warmer, so I'd be happy fermenting at 65ish

Click to expand...

How many BTUs is you A/C?

Magic8Ball said:

That would work, but you would need to locate the coolant lines. Maybe just do a controler on the chest freezer? My back wouldn't like a design like that for me but maybe yours is ok with it. There are a number of builds with window ac units. Just stay away from ones with a digital controler built in. I could never figure a way to bypass it. Drove me nuts.. looks like this:

Click to expand...

Are you talking about bypassing the controller to drop below 60?

twocent said:

Are you talking about bypassing the controller to drop below 60?

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No just put a temperature controller on the chest freezer. Leave the chest freezer whole. It should fit 2 better bottles (check me on that). My brothers used that setup for a while now. (Chest Freezer plus a analog johnson) He makes great lagers.

Well, I came home to my chiller at 19.5 - it's set to 19.6 and the bottles not frozen but still cold 12 hours later. So my work looks to have improved things, but its definitely not there yet. At least I don't have to rush things to get a swamp cooler setup. I can swap bottles back and forth for the next 10 days and work on improving the chamber with an A/C unit later. Maybe I'll brew a Saison next and not worry about this.

Magic8Ball said:

That would work, but you would need to locate the coolant lines. Maybe just do a controler on the chest freezer? My back wouldn't like a design like that for me but maybe yours is ok with it. There are a number of builds with window ac units. Just stay away from ones with a digital controler built in. I could never figure a way to bypass it. Drove me nuts.. looks like this:

Click to expand...

Maybe I'll grab a used chest freezer that can fit two carboys and another stc-1000 and dedicate that to lagers. I'll have my ale chamber and lager box side by side

I just got a chest freezer on CL for $50. Built the STC-1000 and it is staying from 18-18.8°C with no problem, ambient temp is 95°F right now. I had to remove the coils from one of the shelves to fit 2 buckets in there. Build a small basic stand to help with the wait, ans shazaam! The Ferminator is born. Do this and you'll be good to go. Just be very careful when bending as it will crimp easily. Better yet, get one without coils running through all the shelves.

Finished and functional

twocent said:

And you're able to chill down to 60-62? I know fermenting gets a bit warmer, so I'd be happy fermenting at 65ish

Click to expand...

Yes, it can go all the way down to 60. It stops at 60 because that is the lowest setting on the AC unit. I use a Johnsons controls unit to control the temp.

twocent said:

How many BTUs is you A/C?

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I don't remember the BTUs, it was the smallest unit they had at Lowes (about $100-$150) Frigidaire.

Klutz said:

Yes, it can go all the way down to 60. It stops at 60 because that is the lowest setting on the AC unit. I use a Johnsons controls unit to control the temp.

I don't remember the BTUs, it was the smallest unit they had at Lowes (about $100-$150) Frigidaire.

Click to expand...

Badass. With fermentation being a some degrees warmer than ambient, I was worried that if the unit stopped at 60, the lowest it could get is 65-68.

Klutz said:

Yes, it can go all the way down to 60. It stops at 60 because that is the lowest setting on the AC unit. I use a Johnsons controls unit to control the temp.

I don't remember the BTUs, it was the smallest unit they had at Lowes (about $100-$150) Frigidaire.

Click to expand...

Do you have it plugged into a controller, like a STC-1000 and just set for "full blast" when it kicks on? Or do you just have the thermostat set to the lowest?

Sealing a few seams has me comfortable at 65c. There is even some ice left in the water bottles when I swap it out every 12 hours.

I'm still going to go the a/c route just so I don't have to swap bottles continually, but at least this batch is holding steady