Converting a fridge for fermenting beer

Home brewing is a fun and exciting way to make your own beer, the way you like it.  The fermentation process is very temperature sensitive, and off flavors are easily developed if temperatures change by just a few degrees.  Some home brewers are lucky enough to live in a climate that enables them to use a closet or basement to keep the fermenting beer at the correct temperature.  For the rest of us, precise temperature control can be quite difficult.  This instructable will show how I used an old refrigerator and a temperature controller to keep my fermenting beer happy even in the hot sonoran desert.

Step 1 Finding the fridge or freezer

Either a fridge or freezer will work, and they both have their own advantages and disadvantages.  You need to make sure that your fermenter or fermenters will fit inside, and that it cools.  It doesn't matter if the thermostat doesn't function properly, as it can be bypassed.  The first item I found was a stand up freezer listed for free.  Upon inspection, I found that is was not frost free, meaning the cooling coils ran through the shelves, which means they can't be removed to make room for the fermenters.  Make sure to look for a frost free frezer if it's an upright model.  Chest freezers work very well, but can be harder to find.  They have the advantage of keeping constant temperature better when you need to open the door, and most often don't need any modifications other than adding a temperature controller.  A regular refrigerator also works well, and the freezer portion can be used to store hops, cold mugs, and other items.  

I didn't want to spend much money, and because of it's unique use, I could live with a lot of problems that might reduce the price.  I kept checking Craigslist until I found the prefect thing.  It was very dirty inside and out, missing the decorative plastic grill on the bottom, had a broken shelf support, was missing the crisper drawers, and was only $20.  Since it was going to live in my workshop, I didn't care much how it looked, and I'm happy to do a little cleaning to save some money.  I also didn't care about the shelf or drawer issues, as I planned on removing them.

Comments

[scdjw75]

Nice job and an informative post. I'm looking into homebrewing myself and I have just a few quick questions.

How did you run the cord for the temp controller and heater? Were they wired from a power source inside of the unit or possibly drill through an exterior wall and silicone the gap to keep it air tight?

I have an old chest freezer which should work well for fermenting. My concern is having the carboys elevated for secondary fermentation transfer. My thinking is to build a platform for the freezer to sit on approx. 1' to 1.5' feet tall, and then an additional platform inside the unit to give the carboys additionnal lift but keep the overall height at a resonable level.

I'm just trying to work this out in my head and I have no practical experience to speak of. That said, if anyone has some insight please feel free. I'll have to get some measurements regarding the carboys, the freezer may be large enough to do a tier system inside, (my batches would be relatively small).

Thanks again for posting your work, it was a big help.

[roadrocket13]

well done! for my reference, what volume or inside dimensions was the refrigerator that you used for this conversion? it looks like you have just about the right amount of space.

[tashiandmo]

I'm not sure, but I think it was a 19 cubic foot fridge. It died last week when a pack rat chewed through the capillary tube, but I have a second one of a very similar model I plan on replacing it with. I did eventually sell the ranco controller and used the money to buy three panel mount dual stage aquarium temperature controllers. I mounted one in a box making it similar in operation to the ranco, but will mount one directly in the door of the next fridge. I may also remove the area betwen the fridge and freezer compartments or at least make some holes for airlfow so that the freezer compartment will be more useable.

[ewilhelm]

Thanks for posting this!  Your Instructable turned me on to dual stage temperature controllers for my cheese cave.

[t.rohner]

We use 16 gal HDPE fermenters with a "manhole" of about 8 inches. We used to soak it with dishwasher detergent and then cleaned it by hand.
Now we just put them into our commercial size converted bottle/dishwasher.
For fermentation, we use 2 converted freezers, each holding 2 fermenters. They are controlled with homebrewed controllers for cooling and heating. We also use the freezers as work benchs, for example for bottling.
For cold conditioning and storage, we have a walk in cooler.
We just brewed a Munich Helles yesterday...

[iPodGuy]

Oh yeah!  Favorited!

[lemonie]

How do you clean the glass fermentation-vessels?

L

[dafonso]

Powdered brewery wash works excellent as a soak as well. It is a bit expensive, but the fact that it only needs about 30 minutes to most of the job done is a great time saver.

You'll still need a carboy brush to get out the stubborn trub, though.

[Tool Using Animal]

I soak mine overnight and use a carboy brush.

[lemonie]

Soak them in what?

L

[Tool Using Animal]

Water and trisodium phosphate

[tashiandmo]

I usually soak for a day or two with water and oxiclean, and it rinses clean.  If I need to use the carboy right away, then I have to break out the carboy brush.  Some people put a dish rag or a handful of sand in with the cleaning solution and shake it real well, but I prefer to use the brush.

[omnibot]

A cheap replacement I've often used is dishwasher detergent, the cheap kind without shine and stuff.