Temp Controller question

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

normivey

Member
Joined
Dec 28, 2012
Messages
8
Reaction score
2
Location
Columbia
My wife got a new fridge for the kitchen, which means I get a new fermentation chamber. I'm looking at temperature controllers. From what I can tell, controllers work by essentially cutting power to the fridge when interior temperature is below the temperature setting. Does that mean the freezer compartment on on the fridge is useless? (If the freezer compartment works, I may also be able to wrangle a small chest freezer to convert to a kegerator.)
 
When using a fridge/freezer for fermentation the freezer section is likely not going to maintain anywhere near the ~0° that you want for holding frozen foods. I'm not sure where the typical fridge temperature threshold is that the freezer just never really gets cold enough but it's probably somewhere above 45-50°F...

Cheers!
 
If you're desperate, I think you could leave the fridge on as normal and use a temp controller and brew belt (or heat pad) to keep the fermentor exactly where you want it. For lagers this might mean you turn the fridge temp down a little. Either way, it'll be a waste of energy.
 
Wrangle yourself a freezer turned fermentation chamber and use the fridge as a kegerator. This way you can appease swmbo and still have both :)
 
If you've already got a spare fridge or freezer, these are inexpensive and pretty easy to put together -

STC1000s.jpg


It's an STC-1000 controller which you can get on either Amazon http://www.amazon.com/All-purpose-Temperature-Controller-STC-1000-sensor/dp/B00862G3TQ/ref=pd_sbs_hg_10 or ebay for less than $25.

There's an excellent video on YouTube about how to wire it here - as well as several threads around here that are very helpful.

You set the fridge on it's coldest setting and plug it into the cold outlet. I'm using a lamp with a 75 watt bulb for the heat side of things. I had a leftover chest freezer in the garage, so that's what mine gets hooked up to. The temp stays within +/- 0.5C of whatever you set on the controller.
 
Last edited by a moderator:
I never tried it but i would imagine if your fridge had a separate thermostat for the fridge and freezer you could swap the fridge thermostat with a stc-1000 like the post above. Maybe just find the voltage line coming into the thermostat knob and the line going out to the fan that pulls the cold air from the freezer section.
 
If you restrict the air flow to the fresh food area it can be done use the STC-1000 to control the freezer and the heat to turn on a fan to draw cold air from freezer to cool the fresh food area. It may depend on ambient temps as well mine won't keep ice cream cold enough and water takes awhile to freeze But if it's frozen going in it stays frozen, temp holds at 30*-34* while maintaining 50*-52* in the fresh food area.
 
This is the exact question I was just going to ask. Did a search before posting and found this one.

Currently using a typical dorm size 4 CF fridge with the freezer compartment inside the refrigerator section. Have it set up as a fermentation chamber with an STC-1000 controller wired in place of the original temp knob to regulate the temp at 68 F. Use the freezer part to cool and a 60 W reptile warmer heater for heat. I like using this heater because it gives off no light. The controller turns on the compressor when the temp rises and turns it off / turns on the heater when temp drops. I use this to ferment and to bottle condition at 68 F. Problem is I bottle condition for a month and can't brew again until the fridge / fermentation chamber is free. Thinking of getting another dorm fridge but wondering if a full size fridge can be mace to work.

Question - How to make a full size fridge with separate freezer compartment work as a fermenter / bottle conditioner with only one STC-1000 controller? These refrigerators have two thermostats, one for the freezer and one for the fridge. Don't know for sure but think the freezer temp knob controls cold by regulating the flow of freon into the freezer. The fridge temp knob just controls a fan that pulls cold air from the freezer into the fridge, correct?

Does anyone think wiring in the STC-1000 controller in place of the freezer temp knob and allowing the fridges original temp knob to pull cold or warm air as needed into the fridge compartment will keep both the freezer and the refrigerator compartments at 68 F? Where should the controllers temp probe be, fridge or freezer? Same for heater placement, fridge or freezer. Am sure setting it up so the STC-100 controls flow of freon to the freezer with the controller temp probe and heater in the fridge compartment will work. Just may have to sacrifice the freezer space if the freezer section temp can not be regulated.
 
Unless it has two compressors the freezer is the cooling section. The fan moves cool air down a dampener Into the fresh food area the t stat in the fridge controls how long the compressor runs
 
Unless it has two compressors the freezer is the cooling section. The fan moves cool air down a dampener Into the fresh food area the t stat in the fridge controls how long the compressor runs

What Beaks said.

All the refrigerator/freezers I've ever seen have one compressor and one set of coils. I believe that freezer temp is thermostatically controlled while the fridge side temp adjustment is really an air balance adjustment (controlling how much of the cold air from the freezer is exchanged with the fridge.

It comes down to this. You can have that extra fridge do one thing very well. Anything beyond that is going to be hit and miss. Me, I'm grateful that I had an unused chest freezer taking up space in the garage that I could appropriate to precisely control fermentation temps.

The STC-1000 is simply a dual electrical switch that is controlled by a microprocessor. The single temp probe reads the temp (i.e., at your fermentation vessel) and the unit switches power on/off to one 110V outlet (heat) or the other (cold) as needed to keep it at what you set.
 
That's what I thought. STC-1000 will activate the compressor when cold is needed and turn on the heater when more heat is needed. Plan to put the heating element and the temp probe in the fridge section so it will bring the fridge temp up to 68 F as needed.

Cooling I think will be a little trickier. Plan to wire the cooling side of the STC-1000 to the compressor and the fan so both come on when cooling is called for.

This will mean I can not regulate the freezer temp to 68 F so will just not use the freezer section. A little waste of space but then can bottle condition more beer at 68 F in the fridge section. Who knows, the freezer section may reliably regulate the temp to around 68 F and make it usable to bottle condition beer.
 
Wrangle yourself a freezer turned fermentation chamber and use the fridge as a kegerator. This way you can appease swmbo and still have both :)

Thanks to everyone for all the help. I think this is my solution. The freezer compartment of the old fridge is large enough for our needs, and I'll use the chest freezer as my fermentation chamber. The fridge becomes a kegerator somewhere down the line. For now it will just hold lots of beer--homebrew and otherwise.:)
 
That's what I thought. STC-1000 will activate the compressor when cold is needed and turn on the heater when more heat is needed. Plan to put the heating element and the temp probe in the fridge section so it will bring the fridge temp up to 68 F as needed.

Cooling I think will be a little trickier. Plan to wire the cooling side of the STC-1000 to the compressor and the fan so both come on when cooling is called for.

This will mean I can not regulate the freezer temp to 68 F so will just not use the freezer section. A little waste of space but then can bottle condition more beer at 68 F in the fridge section. Who knows, the freezer section may reliably regulate the temp to around 68 F and make it usable to bottle condition beer.

The fan will already work that way that's how the all work so you just need to power in.
 
Does anyone find the heating element necessary? My understanding was that it was just an issue of turning on and off the power to the fridge/freezer.
Does the extra cost of the heating element warrant itself with a more precise temp control? Or will the fluctuation in temp remain relatively the same?
 
perrypainter said:
Does anyone find the heating element necessary? My understanding was that it was just an issue of turning on and off the power to the fridge/freezer.
Does the extra cost of the heating element warrant itself with a more precise temp control? Or will the fluctuation in temp remain relatively the same?

It is necessary for me in the winter. I ferment in my garage and it can get colder than a fridge/freezer will insulate against. We had an extended cold period this year and I had water bottles freeze in my garage.
 
Okay. but for somewhere like San Diego, it wouldn't necessarily keep a more precise temperature? Still about 2-3 degrees F variance?
 
Okay. but for somewhere like San Diego, it wouldn't necessarily keep a more precise temperature? Still about 2-3 degrees F variance?

No you'll be fine that variable in temp will only be in the ambient temp of the fridge the fermenter due to it's thermal mass will only move 1/2 a degree or so. I monitored mine for 4 batches using both seasons here. :D
 
No you'll be fine that variable in temp will only be in the ambient temp of the fridge the fermenter due to it's thermal mass will only move 1/2 a degree or so. I monitored mine for 4 batches using both seasons here. :D

PERFECT! thanks, I am still deciding whether to build this or just spend the 60 bucks on the digital johnson controls one. Or spend $130 at my LHBS so I can brew tomorrow!
 
PERFECT! thanks, I am still deciding whether to build this or just spend the 60 bucks on the digital johnson controls one. Or spend $130 at my LHBS so I can brew tomorrow!


Why not spend $30 and build a dual control box using an STC-1000?
 
Why not spend $30 and build a dual control box using an STC-1000?

yeah now I'm leaning that way again. Even though it's San Diego, It still will drop to 40 degrees in the winter. I would still have to buy a heater but if I'm trying precicely control the temperature i might as well build the controller dual and get a heating element. I dont remember if I've seen it before, but what is the recommended heating unit for a kegerator? I think I saw somebody say they got a reptile cage heater?
 
Okay sorry for over posting on this; last question, I promise!
Can anyone tell me if the temp probe sent with this unit will suffice, or should I be shopping for a beeter one? If I should get another one, which one would be best?
And thank-you to everyone for being patient and helpful with this, you don't know how helpful this really is.
 
I had a heater in mine for the just what if's along with a cycle counter and a 7 degree differential and after a year and no cycle counts, even with a couple of dips outside below 30*s. So now I have a 1* differential that runs a fan for about 2-5 minutes after a cooling cycle. The probe that is provided is just as good as the OEM.
 
Back
Top