Freezer top/fridge bottom fermenter conversion

[bwookie]

I recently got an incredibly good condition/fairly new freezer top/fridge bottom for free and want to convert it to a fermenter bottom, while still keeping the freezer top freezing....

Everything i have researched is old info and states that there really is no way to keep the freezer able to freeze as it should while fermenting in the 60s....is this still true? Or are there workarounds?

Im hoping i can get it to work, or would it be best to try to sell and pick up a single unit?.... The wife wants the freezer to freeze part and i want the fridge/fermentor...

Any links/builds would be greatly appreciated, ive been researching for a month now and feel like ive come up dry, with a little hope from some old posts but no how-tos

Thanks in advance!

 

[JLeuck64]

Yup, I got a freezer top/fridge bottom for free from a buddy. The thing runs perfectlcy so I built one of those STC1000 dual temp controllers for it and with a custom built shelf I can ferment 15Gal down low with no problem. Several years later this is still an awesome fermentor! It will cool or heat in the bottom to within a couple of degrees and my beers definitely improved with the temp control during fermentation. The best I've been able to do, during the summer months, is keep drinking water or soda or beers cool in the freezer compartment up top. It's not such a bad thing when you think about it. Having cool drinks up there helps the thermal cycling that goes on when the fridge is cooling the beer down below. Since we put the temp probe in the lower half, fridge section, it commands the unit to turn on when necessary. The cooling comes from the upper half, freezer section, so when the thermal mass is colder up in the freezer section the the faster the lower section will cool down. Works great to keep drinks cool that are stored up high during the times of the year the refrigerator is running but that's about it from my experience. Once the STC1000 switches over to heating for the bottom section then the upper section will just stay at about ambient temps approximately.
HTH ( ;

 

[Sadu]

I got this working on my fridge freezer. It is an amazing setup, works so good.
You need a fridge that uses thermistors instead of a thermostat. New fridges should have this. You will need a STC-1000, some different sized resistors, a multimeter, thermometer and cables. Some experience with electronics or a friend who does would be very helpful.
Mine took about 1 hour to wire up, but I found a thread here by a guy with the same model fridge as me. Will post the link when I get home.

 

[markstache]

Everything i have researched is old info and states that there really is no way to keep the freezer able to freeze as it should while fermenting in the 60s....is this still true? Or are there workarounds?
!/QUOTE]

There is a fan between the fridge and freezer. When the fridge portion is too warm, the fan blows cold air down from the freezer to cool it. You can wire a temp controller in series with the fan to control it yourself. I've heard that you can also adjust the built in thermostat by a set screw, but I have no experience there.

 

[Sadu]

OP, here is the thread I mentioned and a bit more info.
https://www.homebrewtalk.com/showthread.php?t=597754

So I guess there are a couple of ways you could go. The way I did it requires a bit more wiring but is a good clean solution. As noted you get to keep the freezer working normally and the fridge lights still come on when you open the door. This method requires a fridge that uses thermistors - if you have any digital sort of temp control inside the fridge then it probably has thermistors. eg I push up/down buttons in my fridge, and LEDs light up to show what temp I just set. Old fridges have a manual knob which you turn to set the temperature, these use a thermostat which won't work with this method. There are links in that thread which will help you if you want to go this way, and I'm happy to answer questions if I can.

The other way mentioned above is to utilise the fan between the fridge and freezer compartment. Most newer fridges cool the freezer only, and there is a duct and fan that pushes air from the freezer into the fridge as required. What you need to do is disconnect the fan and connect it via your STC-1000 and a 12v power supply. This way you control when the fan comes on. This is probably the simpler method of the 2.