Mini Fridge

[redrocker652002]

Well, seems the best laid plans sometimes just don't want to work out. My hope was to expand my mini fridge and be able to store kegs and lager them in the 40's. Seems that the fridge is struggling right now to keep itself in the high 40's. So, I might end up just putting it back to a single bucket fermenting chamber and bide my time until I can get a freezer and then I can store and tap multiple kegs at a time. Kinda disappointed, but it is what it is.

On the plus side, I now have a fan that I might try and use to make a diy stir plate. I saw a cool one on Youtube. Fairly cheap and with having the most expensive part already here it might be a fun project.

 

[Skeeter686]

I tried something similar and had similar results.

The fridge seems to do fine with maintaining temperatures into the 50s, but it struggles with 40s or below. And I guess I shouldn't be surprised... it was a little cube dorm fridge and I expanded it to probably 5x its original cooling volume. (Or more, probably! )

 

[redrocker652002]

I tried something similar and had similar results.

The fridge seems to do fine with maintaining temperatures into the 50s, but it struggles with 40s or below. And I guess I shouldn't be surprised... it was a little cube dorm fridge and I expanded it to probably 5x its original cooling volume. (Or more, probably! )

Yea, mine is a dorm style fridge my brother left at my mom's after he moved out. So I took it figuring I could use it as a nice fermentation fridge. In the 50's it is solid, but at 48 it seems to turn on and off a lot. I don't want to burn the motor up, and to be honest I don't see myself doing more than one batch at a time. If I do, I can always just put the keg in my closet where it is usually in the mid 60's then figure to let it sit in the serving fridge for a bit longer to cool back down. Either way, I think the idea of having multiple batches running is a pipe dream for now.

 

[Ramjet]

I use a small dorm fridge that had a freezer and removed 2of the screws and bent it down very carefully to avoid breaking the coolant lines. It will go down to 20 degrees no problem. I control it with an INKBIRD.

 

[mac_1103]

I use a small dorm fridge that had a freezer and removed 2of the screws and bent it down very carefully to avoid breaking the coolant lines. It will go down to 20 degrees no problem. I control it with an INKBIRD.

But did you expand it (i.e., with a collar)? I think that's the cause of the issues the other posters are having. My fermentation chamber is a freezerless minifridge with a 2x6 collar and it's fine down to cold crash temps. But the collar only added about 1.5 cf to a 4.5 cf fridge. I probably could have and should have done a bigger collar, within reason.

 

[Ramjet]

But did you expand it (i.e., with a collar

No I did not (yet) I ferment in a 6 gallon fermonster or bucket which just fit on the shelf. Or in a corny keg within the shelf

 

[redrocker652002]

I expanded mine with 2 2x4's to make it so I could store 2 kegs or a keg and a bucket. My thought is maybe the added would is absorbing some of the cold as the wood on the outside is cool to the touch. I am thinking of either trying some thin sheet insulation or painting the inside of the wood with either a thick coat of paint or some sort of insulation type stuff. Maybe that might help.

 

[mac_1103]

I am thinking of either trying some thin sheet insulation or painting the inside of the wood with either a thick coat of paint or some sort of insulation type stuff. Maybe that might help.

My 2x6's are painted inside and out, but not insulated. The collar is not any cooler to the touch than the door. Ambient in the corner of my basement where the fridge lives is in the low to mid 60's. I'm sure that helps keep the compressor happy.

 

[Skeeter686]

But did you expand it (i.e., with a collar)?

A collar? No, sir.

I was bored during the pandemic. Mine is a completely overbuilt, insulated cabinet, with the dorm fridge attached on one end. I could possibly fit four carboys into the cabinet, plus whatever fits into the actual fridge, itself.

I freely acknowledge that I overdid it.

 

[IslandLizard]

I expanded mine with 2 2x4's to make it so I could store 2 kegs or a keg and a bucket. My thought is maybe the added would is absorbing some of the cold as the wood on the outside is cool to the touch. I am thinking of either trying some thin sheet insulation or painting the inside of the wood with either a thick coat of paint or some sort of insulation type stuff. Maybe that might help.

Wood is a poor thermal insulator.
Insulating the inside of the box with 1-2" of rigid insulation, could make all the difference. Make sure every square inch is clad with the foam, no voids.

I've seen fermentation chambers built from just 2" rigid foam, with a refrigerator or a window-type AC unit chilling the inside of them.

 

[redrocker652002]

So, I was thinking of using this. Thoughts?

https://www.homedepot.com/p/Henry-1-in-x-48-in-x-8-ft-R-3-85-Insulating-Sheathing-320821/202532854

 

[Skeeter686]

So, I was thinking of using this. Thoughts?

https://www.homedepot.com/p/Henry-1-in-x-48-in-x-8-ft-R-3-85-Insulating-Sheathing-320821/202532854

I'm guessing that should work. I used a different brand, but I assume they're similar.

One thing to keep in mind is that you have to use the right adhesive. If you just pick up the regular Liquid Nails and apply it to a foam board, it'll likely melt the foam.

You seem pretty handy so you probably already know this, but I thought I'd mention it, just in case.

 

[mac_1103]

One thing to keep in mind is that you have to use the right adhesive. If you just pick up the regular Liquid Nails and apply it to a foam board, it'll likely melt the foam.

This product looks to be faced on both sides, which should increase the range of compatible adhesives.

 

[redrocker652002]

Thank you both for the replies. I actually did not realize I would need to use an adhesive. My plan was to cut the boards tight and use tape for the seams. But now, I see how that would have been a very faulty plan indeed. So, my plan at this point is to go get the sheet, adhesive and measure it out. Cut and apply the adhesive and stick to the walls. The ceiling might be a bit more to deal with as I have a bucket in there now lagering at about 48 degrees. So, my thought is to maybe try a couple of 2x4's to use as supports to keep the insulation on the ceiling of the fridge until it dries. Hmmm, this might be a bit more than I thought. Either way, I am going to give it a go. Nothing to lose but a bit of time and about 30 bucks. LOL

 

[Skeeter686]

My plan was to cut the boards tight and use tape for the seams.

That could potentially work. I used adhesive and that seems fairly common, but if the pieces fit well and tape is all you need, then maybe you can simplify. The tape could seal the seams and hold everything in place, too.

I haven't tried this, but it could work. And if it doesn't, I'm guessing it would be easy enough to redo it with adhesive later, if required.

 

[Slim M]

I expanded mine with 2 2x4's to make it so I could store 2 kegs or a keg and a bucket. My thought is maybe the added would is absorbing some of the cold as the wood on the outside is cool to the touch. I am thinking of either trying some thin sheet insulation or painting the inside of the wood with either a thick coat of paint or some sort of insulation type stuff. Maybe that might help.

You might try adding insulation to the outside if it’s easier, but I would make sure all the joints everywhere are totally sealed with silicone or something on the wood.

Anytime you expand anything I think it’s definitely a good idea to add some PC fans or something for circulation. On chest freezers with a collar, I usually add one fan set to pull cold air up from the bottom and another one trying to circulate it horizontally. I might have it all wrong, but it seems to work.

Usually set my temp differential at 2 degrees f during fermentation and around 7f when no fermentation. When not fermenting my fermenter is stored in the chest freezer chamber with a couple gallons of star san in it and I stick a few gallons of water in there for thermal mass and set the temp in high the 50s.

All that mentioned above helps with the cycling. This thing stays in a hot metal building seems to do OK in the summer. In the warmer months, I do lean more towards warm for men loggers with fermentation temps in the low 60s to ease some of the stress. Sorry for rambling, but maybe some of that I mentioned might help somebody.

 

[redrocker652002]

Great info, thank you so much. I do have a small fan in the fridge to help with airflow and it seems to help. I think lining the inside is going to be best, I just need to get in there and do it. I will more than likely get to Home depot today or tomorrow and buy a sheet of 1 inch sheet insulation and some adhesive and try it out. Should only take a few hours and if it works my problems will be solved. Thanks to all who replied. I will update the threat and please keep the info coming. Dino

 

[mac_1103]

One advantage of putting the insulation on the outside is that you won't make the inside of the fridge smaller.

 

[redrocker652002]

One advantage of putting the insulation on the outside is that you won't make the inside of the fridge smaller.

Very true, but won't that keep the heat in when the motor is running too? Plus, this is in the corner of the room where people can see it. I am pretty sure my wife is not going to go for the idea of it being wrapped in insulation. LOL.

 

[mac_1103]

won't that keep the heat in when the motor is running too?

Not if you only insulate the collar. The refrigerator walls are already insulated.

 

[redrocker652002]

Not if you only insulate the collar. The refrigerator walls are already insulated.

I am going to give that a go and see what happens. At least as a temp fix until I can get the beer finished and in a keg that is in the fridge now

 

[redrocker652002]

Well, it did not work. I bought the thinner stuff just to see and it seems the temp rose and was losing about a degree every 5 minutes or so. I got mad and took the whole thing apart only to find that the seal for the door was compressed so bad it would not seal when put back to it's normal state. Next up, 1 inch thick foam sheet insulation on the inside and the collar goes back on. If this doesn't work, I am going to just have to look at Craig's list and see what I can find on the cheap. thanks to all who replied. I will keep this thread going with updates. Feel free to add any info, I appreciate the input.

 

[redrocker652002]

Update to the "project". I ended up getting the 1 inch thick sheet stuff. make sure all the seams were sealed and the door was even layered with the sheet stuff. I plugged it in and waited. It went down to about 44.5 or so, perfect right? Well, as I went on with my day I watched the temp slowly climb back up to about 48 or so. I have the inkbird set to turn on at 3 degrees above and below 45 so it turned on. I just think that maybe being that I added a 2x4 and a 2x6 I may have just made it too big to handle the temps and keep them there. I am ok, at least kinda, if it has to turn on for 5 or so minutes every so often the stay within 45 and 48, but I don't see this as a long term solution. The last change is to add a layer of weatherstripping to the door opening to make sure the door is sealing properly. Other than that, it is still good with frem temps in the 50's and 60's but probably will not be any good for keeping kegs as cold as i hoped. Thanks for all the input.

 

[mac_1103]

So just how small is this fridge without the collar? IOW, how much extra volume are you asking that compressor to cool? Also, how old is it? IOW, could it be that your problem doesn't have anything to do with the collar?

 

[redrocker652002]

So just how small is this fridge without the collar? IOW, how much extra volume are you asking that compressor to cool? Also, how old is it? IOW, could it be that your problem doesn't have anything to do with the collar?

It is a small Daewood Mini Fridge I think. I am at work so not sure about the size. I added about 10 inches total of collar to it. I attached a 2x4 and 2x6 together and then attached it to the fridge. I honestly think I just put too much collar to it and now it is just not able to handle the amount of space. It still does what it is supposed to do, but just fluctuates about 2 to 3 degrees and the motor will turn back on. I am going to look for a used chest freezer I think or just buy a new one for less than 200 bucks to cold crash and store kegs if I ever get to the point where I need to start storing them. Right now, I am going to go back to my having one fermenting when I think the one I am drinking is getting ready to kick.

 

[IslandLizard]

I am going to look for a used chest freezer I think or just buy a new one for less than 200 bucks to cold crash and store kegs [...]

Just beware what you're in for with a chest freezer.
Volume, space layout inside (they all have a hump!), and maximum inside height are important parameters for suitability.

You need to be strong enough to lift filled and heavy fermenters in and out of it. It can also be a bit of a hassle as they tend to be slippery especially when they don't have adequate lifting handles. Even full size (6.5 gallon) fermentation buckets, which do have a lifting bail/handle, take some serious effort, mostly on your back and arms. Some brewers rig up a hoist to make loading and unloading easier and safer.

Chest freezers have plus points, aside from using as a kegerator, but I prefer using upright fridges and freezers for fermentation related tasks.

 

[redrocker652002]

Just beware what you're in for with a chest freezer.
Volume, space layout inside (they all have a hump!), and maximum inside height are important parameters for suitability.

You need to be strong enough to lift filled and heavy fermenters in and out of it. It can also be a bit of a hassle as they tend to be slippery especially when they don't have adequate lifting handles. Even full size (6.5 gallon) fermentation buckets, which do have a lifting bail/handle, take some serious effort, mostly on your back and arms. Some brewers rig up a hoist to make loading and unloading easier and safer.

Chest freezers have plus points, aside from using as a kegerator, but I prefer using upright fridges and freezers for fermentation related tasks.

Great points and I agree. Getting up in age means the back is always a concern. I think you are right, and to be honest this fridge is doing it's thing just a bit of a struggle in the colder temps. I will see what I can find in the Craigslist world or see if anything goes on sale. Thanks to all who replied. Keep it coming as I learn something new every time.

 

[redrocker652002]

So just how small is this fridge without the collar? IOW, how much extra volume are you asking that compressor to cool? Also, how old is it? IOW, could it be that your problem doesn't have anything to do with the collar?

Updated reply to your post. While I did not measure the inside of the fridge, I worked last night and was tired, I did measure the top outside to get an idea. So, the depth of the fridge is about 19 to 20 inches I believe. The collar added about another 9 inches of depth to the unit. So, with that said, I think I may have overshot the unit's potential and it is struggling a bit. It is still doing it's thing, but having to turn the motor on about every 15 to 20 mins for a few to get it back to the 45 or so I am asking it to maintain. I have felt the side of the unit and while it is a bit warm after it runs it is not hot so I think at this point I am ok.

 

[Indian_villager]

Do you have a circulation fan by the coils? I found this helped me greatly with my dorm fridge that I expanded out with 2x6s. Without the fans the coils would just ice up and then the ice just insulates the coil.

 

[redrocker652002]

Do you have a circulation fan by the coils? I found this helped me greatly with my dorm fridge that I expanded out with 2x6s. Without the fans the coils would just ice up and then the ice just insulates the coil.

Yes I do. It is sitting on the ledge just under the coils. Maybe I need to try and perch it up a bit?