What size fermentation chamber to build?

[Mountainsax]

I am planning to build a couple fermentation chambers but wanted some thoughts on size. I am planning on using the guts from a mini fridge and a paint can heater. I was thinking of making the chamber 24x24x36. I started thinking that if it was a little wider, say 24x36x36, I could fit two carboys.

Does anyone have an idea if a mini fridge system could cool this enough to lager?

 

[fergusmj]

I think a lot would depend on the insulation of your fermentation chamber you make. I have a mini fridge that I converted to a ferm chamber and wish I could do 2 batches at once, so if it were me, I would go for the 2 carboy setup personally. Nice to have if I want to do 2 batches at once, or let one of my buddies brew a batch. Stinks having to wait to brew because you have one fermenting already. Granted though, after about a week, it's not a big deal to take it out of the fermentation chamber as the precise temperature control is not as big of a deal. My house is 70 and ferm chamber is 65 or so. After a week or after I transfer to 2ndary, I just set the bucket inside since the yeast has already done it's thing usually.

Good luck!

 

[Mountainsax]

I was planning to use 1 1/2" foam board for the insulation, mainly because it is the se size as the wood. I have read s few things here about putting air space between the foam layers for better insulation, but still need to do more research.