Dual Fermentation Chamber Build--Will It Work?

[tennesseean_87]

So I have finally moved somewhere that I can have a fridge to do lagers! I'm still probably going to do a dorm-sized fridge rather than a full upright, though. After thinking about doing two beer at once, I came up with this idea:

Mini fridge w/ door removed controlled by STC-1000 --> extension built from 2" polystyrene board --> removable PS divider w/ fans to bring cold air into second chamber (second STC-1000).

Each stc-1000 will also control a heater (paint-can, ferm-wrap, etc.). I'll probably go with a removable lid to get stuff in and out. The colder beer will always go in the fridge section, and the warmer chamber will draw that cooler air through when it's temperature needs to drop. I may wire a fan to circulate air in the primary chamber when the fridge is running if it seems beneficial.

Here are my questions:

1. How big of a mini-fridge do I need? There are some smaller ones on CL that won't fit a fermenter, but if I just use an extension to actually hold the fermenters, will a smaller dorm fridge be able to drop the primary chamber to lager temps?

2. Will this be able to run in a garage in Bismarck, ND? It can go in the laundry room if absolutely necessary, but the missus might like it better out in the garage. It's non-heated, detached from apartment building, but side-by-side with other garage stalls. I don't know how cold it will get in the winter, or if that might be bad for the fridge or whatever heater I will be using.

 

[aaronmq]

1. How big of a mini-fridge do I need? There are some smaller ones on CL that won't fit a fermenter, but if I just use an extension to actually hold the fermenters, will a smaller dorm fridge be able to drop the primary chamber to lager temps?

Can't really speak to your second question, but check out this build for what you are trying to accomplish:

https://www.homebrewtalk.com/showthread.php?t=538078

I think you would be better off with a mini-freezer to accomplish lager temps, like the build in the link. I was planning on doing a build similar to this; however decided against it because I figured it would cost me at least $300. And because my fermenters are going in the garage, I'm not too concerned with how it looks. That being said, I can buy a couple of mini-fridges brand new for under $300.

 

[tennesseean_87]

Can't really speak to your second question, but check out this build for what you are trying to accomplish:

https://www.homebrewtalk.com/showthread.php?t=538078

I think you would be better off with a mini-freezer to accomplish lager temps, like the build in the link. I was planning on doing a build similar to this; however decided against it because I figured it would cost me at least $300. And because my fermenters are going in the garage, I'm not too concerned with how it looks. That being said, I can buy a couple of mini-fridges brand new for under $300.

I'm definitely not going for something that big right now. I guess my question is about the difference between a mini fridge and mini freezer. Is it just the thermostat sets the freezer to lower temp, or is there more oomph in the mini freezer to cool a larger area? Or is just that without messing with the fridge electronics I'm not going to be able to get down to 34F and have to go for lagering at 38-40?

 

[tennesseean_87]

I guess my next thought is that if I can get a chest freezer, I could make a one/two-fermenter-sized box to sit right in the freezer and have a small hole for a fan to bring the cool air in for ales and leave the outside part operating on the STC-controlled freezer for lagers. This might work better for the future if I want to turn it into a keezer.

Maybe that wouldn't be enough insulation to give me the temperature difference to do an ale fermentation while a lager is going. Maybe a collar with a vent to a side chamber would be a better option.

Does anyone else have any suggestions? I have some of the board already, but the budget may not allow for two fridges and ingredients given the current CL market in Bismarck right.

 

[tennesseean_87]

Update: I picked up a mini freezer for $20 on CL. I looks like I'm headed back to the original plan, but without being able to get the fermenters in the freezer because the shelves are integral to the cooling system.

I'm thinking I might only use one heater, for the warm chamber. I would then be able to just turn the fans on when either the warm chamber is too warm or the cool chamber is too cool. Several builds use one cooler and circulate air, so why not do the same with the heat?