Fermentation Chamber Temperature Controller

Between fermenting beer and fermenting peppers I do a lot of fermentations and they all require different temperatures for optimal fermentation. Fortunately, a hot pepper mash usually will ferment between 85 and 95 degrees F (29.4 and 35.0 degrees C) and the ambient temperature for Central Florida is very nice about complying with that need.

Fermenting beer is a totally different matter though. Higher temperatures are not good as they can cause off flavors and Fissile Alcohols to be created in the beer.
To give me more control over fermentation temperatures I’m using our garage refrigerator and building a Temperature Controller which will turn the refrigerator on or off as needed to maintain the proper temperature for the beer. This includes being able to lower the temperature to lager. Note: the controller can also be used to control a Kegerator.

I have seen numerous plans on the internet for these and have adapted this one from several of them. Since I’m using a refrigerator that won’t always be full of fermenting wort I’ve added a bypass switch to allow the fridge to work normally.

Suppliers:
EBay:
STC-1000 Available from numerous sources (12 VDC, 110 VAC, 220 VAC) ranging from $15.00 to $25.00 US.
Radio Shack:
Project Enclosure $6.49 US
4 Position Terminal Block $2.49 US
Size N D/C input Plug and socket $10.00 US
10A / 125 AC SPDT Switch $8.00 US
Hook up wire, min 22 gauge, in 3 colors (lead, neutral and ground) $8.49 US
Lowes:
20 Amp Duplex Outlet with removable bridge $5.97 US

My total cost was $52.94. I picked up my STC-1000 for 19.99 with free shipping and I have a ton of PC Power Chords around and stripped my wires out of one.





Wiring Diagram.
This first diagram includes the bypass switch.


And without the bypass switch it would look like this


The controller used in this is the STC-1000 which is designed for use with Aquariums. Also it only reads in degrees C. The colors used for wires in the diagram are:

Black for the Load (P) black in the build
Blue for the Neutral (N) white in the build
Brown for Ground (G) green in the build

The A/C in is a 3 prong plug in like you would find on any computer. The wires off of this go into a Terminal Block.



From the Terminal Block the wires go out to:

Positive (P) 4 wires out

1. Connector 1, the STC-1000 power positive connector
2. Connector 5, the Cool In
3. Connector 7, the Heat In
4. Connection on the Bypass side of the SPDT switch.

Neutral (N) 2 wires out:

1. Connector 2, Power negative connector
2. Negative (silver) connector on the outlet

Ground (G) connects to the outlet ground connection

This leaves connections 3, 4, 6 and 8 on the STC-1000 unconnected.
Connections 3 and 4 are for the Temperature sensor.
Connection 6 will go to control side of the switch if you’re using the Bypass or the Positive side of the Cool plug if not.
Connection 8 will go to the positive side of the Heat plug.
If using the Bypass Switch, the center position connector from the switch is then wired to the Positive side of the cool plug on the outlet.
Parts that don’t have screw mounts, such as the Terminal block, can be hot glued to the box.

Steps:
1. Mark the positions for the cuts to be made into the case for parts mounting.



2. Cut and shape the holes. I used a Dremel and it was really simple. If you had to use a Craft Knife it could be done but would be tough going and time consuming.

3.Remove the bridge from the Hot (Brass) side of the Duplex Plug and mount it, the Sensor Plug socket and the STC – 1000 and drill the holes for the screws where needed.



4. Solder wires to the 3 posts on the A/C input, sensor plug and socket and bypass switch if you’re using one.

5. Attach wires from Sensor Plug socket to the STC – 1000 (3 and 4).

6. Run wires from A/C input to the Terminal Block.

7. Run wires from the Terminal Block (P) to the STC – 1000 (1, 5, 7), Bypass Switch (Bypass) and the Duplex Plug (N, G).

8. Run the wires from the Bypass Switch (Control) to the STC – 1000(6), Bypass Switch (Center) to the Duplex Plug Cool side and from the STC – 1000(8) to the Positive side of the Heat plug.
Note: If you’re not using the Bypass Switch then the wire from Connection 6 (Cool Switch) on the STC – 1000 will connect directly to the Positive side of the Cool Plug.

9. Close up the box and place the Bypass Switch into the Center (off) position.

Setting your new Temperature controller up for use.

1. Plug the Controller into the wall outlet. It’s ok if the STC-1000 comes on as the Bypass switch is in the Center (off) position.
2. Plug the Refrigerator into the Cool Plug.
3. Plug your heat source, a reptile warmer works well as a low cost warmer, and place it inside the refrigerator.
4. Switch the Bypass to Bypass and the refrigerator should come on.
5. Program the STC-1000 per the instruction sheet.

Note: the STC-1000 is in Degrees C

1. Go Brew some Beer.
2. RDWAHAHB!!!!

Tools:
Cross Tip Screwdriver
Flat tip Screwdriver
Needle Nose Plyers
Wire Cutters
Wire Stripper (if you’re no good at stripping wire)
Drill with bits
Dremel with cutting and routing attachments
Soldering Iron
Solder

Still have a few more pics to upload and post so check back. If you want to build one and have questions send a PM.

Cheers y'all,
RM

Nice write up man! This will be a life saver for me. Do you know if the controller allows a couple degrees on either side of the temp as to not kill the compressor of the fridge from turning on every few minutes?

It has what they call a Difference set value which has a range of 0.3 to 10degrees C as well as a compresson delay time setting which has a range of 1 to 10 minutes. It's a pretty cool little unit. I'm thinking about getting another one when I build my Kegerator but that'll be a while yet.

Ok, good deal. I recieved my temp controller (same as yours) a couple weeks ago. Your write up makes it seem not AS bad. So I may rig up that freezer soon. Or at least die trying

Bill, pass me a beer and a shot of some Rocketfuel:-)

romy6 said:

Bill, pass me a beer and a shot of some Rocketfuel:-)

Click to expand...

Man, that gives a bit of a new meaning to a Beer and a Shot

Humm, which do you do first?

Final pics









Cheers,
RM

ohhh thats sexy

Thank you Sir, I thought so too and it's working nicely chilling the forst 3 gallons of water for brew day Monday. Kool Yule Porter

Well the controller is now up, running and controlling the temp like a champ.





That's the fridge plugged into the Cool side and I have a large Heating Pad plugged into the Heat side. I set the Temperatrure to 18.0 degrees C (64.4degreesF) and the difference to +/- 0.5 degrees C and I have yet to come out and catch the fridge running though the heating pad was on for a while last night while it worked to pull the temperature up. All in all I'm very happy with it.

Lessons learned during the build

A dremel tool with the cutting blades and a sanding or grinding tip is a total +10 for this project. Just to see how bad it would be I tried cutting just one hole with a Craft Knife and after 15 minutes grabbed the dremel.

Your going to want a powerful Soldering Iron for this. I have several icluding one very expensive one designed to protect Motherboards from stray voltage and in the end I went to my Butane powered one. if you don't have one like that I'd suggest a Soldering Gun with HIGH temp capability.

While this project will fit into a 6x4x2 box, which I had purcchased and had planned on using, after looking at the pieces laying next to the box I went and picked up a bigger box. I am thinking about using the smaller one for my Kegerator build though as there will be only 1 plug outlet.

I used to work as a PC Tech and had alot of Power Supply Units around, some of which were inop. Stripping out the plug port from one was easy.

Cheers,
RM

Wow what a project!!!!

I just bought a little collage refrigerator; tore out the door panel and shelves and bent down the little drop down freezer compatment. Near instant controllable beer and wine cooler. No fuss little mess and good for a 5 gal pressurized soda container for tapping that same beer.

Balac, this is a really simple project and if you dont have a soldering iron or just don't like the idea of soldering then there are no soldier ways for it to be done. Using the controller you could use the fridge to ferment the beer by uping the temp to like 18.4 degrees C (64 F) and then when its done and kegged and the keg has conditioned just crank the temp down and after it's chilled through your ready to serve and your little fridge has served dual purpose.

I was looking for a new STC-1000 for a new project and found this on Amazon. It's the STC-1000F which is programmed for Fahrenheit instead of Celsius.  
 

 
and just $20.00 with shipping, Done!

Hey RM -
 
Very interested in your opinion on this one, too ...
 
I'm having a hard time deciding what to do on this subject ...
 
All input appreciated!!!

There's several ways to go on that one Grant, some of which can set you back over several hundred dollars. I think the best solution uses parts available at Lowes or Home Depot and with the directions from here:

http://byo.com/issues/item/362-build-a-counterflow-wort-chiller
The article says they built one for $39.00. If you sunk it in. Big tub of water and froze it then I'm betting it'll chill your wort in nothing flat.

There's several ways to go on that one Grant, some of which can set you back over several hundred dollars. I think the best solution uses parts available at Lowes or Home Depot and with the directions from here:

http://byo.com/issues/item/362-build-a-counterflow-wort-chiller
The article says they built one for $39.00. If you sunk it in. Big tub of water and froze it then I'm betting it'll chill your wort in nothing flat.


i linked to the wrong reply in the thread, sorry.

i'm inquiring re: fermentation storage ...

regular hpusehold fridge/freezer, versus pair of pid-controller chest freezer's, versus something + kegerator ...

it really kind of feels like a small squad of pid-controlled five cubic footers might be my best bet ...

Well they would allow you to control each one at a different temp it you needed to, so Yeah they would be best.

Found this while cruising Home Brew Talk. I haven't had a chance to check it out closely yet but if it's good it will really go a long way towards making the STC-1000 a great part of your controller for your fermentation chamber.
 
Here's part of what he has to say, link at the bottom.
 
Quote:
"The firmware I provide, features 6 programmable profiles, 10 setpoints each with 1-999 hours between setpoints. You can also set hysteresis, temperature correction offset, cooling delay, you can change current step and duration in the running profile and you can set current setpoint, finally you can choose and run profile or simply thermostat mode.
Right now programming is made by sending the HEX file through the Arduino usiing a serial terminal emulator that supports sending files (I use CuteCom in GNU/Linux). But once I reach something that I feel is good enough I'll provide the option to embed the HEX in the sketch and you'll just need the Arduino IDE to (user friendlier to the non-developer).

The programming header ont the STC-1000 is a bit difficult to reach from the top, you might have better luck on the bottom of the board. I have provided a picture of my dev board, but in it I have already soldered in a pin header."
 
Link: Click Here

yup, I have that repo forked on github, actually ... there's a rich history of computer programmers homebrewing! ...
 
thanks for sharing.

Oh,