Jan 11, 2011
$100 DIY cheese vat/sous vide circulating water oven
I love cheese.
So does Yoav Perry, our friend and neighbor who makes, invents, and ages his own cheese.
Yoav’s idea is to make a digital cheese vat based on our $50 dollar sous vide. Since temperature control is essential for cheesemaking, we are on the same precise heating page. He purchased a discount double-pan roaster at Kmart to serve as the water oven. We then hatched plans to replace the innards of the roaster with the sous vide components.
This post gives details of the technical aspects, but please enjoy Yoav’s account of the construction as well.
UPDATE: We now have a kit to build your own sous vide controller for $80! It requires soldering, but we think it produces an elegant and convenient result.
- Roasting oven (Yoav found this Oster 22-qt oven on sale for $30; Amazon)
- JLD612 PID controller (Lightobject)
- Pt-100 RTD temperature sensor (Lightobject)
- 25A Solid state relay (Lightobject)
- Aquarium air pump (Amazon)
- Aquarium air tubing (Amazon)
- 2 feet of high temperature wire (18 gauge)
- Ring and spade terminals (18 gauge)
- Electrical tape
As always, please build anything you plug into a wall at your own risk.
NB: serious hackers! We have a quickie MAKE guide.
We first disassemble the roaster– we unscrew the bottom, remove insulation, and detach the thermostat. The wiring is very simple, but the roaster’s thermostat is difficult to remove.
At first we weren’t aware our wires needed to be high-temp safe so we used basic double stranded wires (as seen above). Disastrously, during our trial run our wires started melting– so now we write instructions now to fit our high-temp safe single strand wires.
Prep four high-temperature wires. Two will be the power cords, so we attach ring terminals on either end. The other two will control the relay, so we attach spade terminals. Check that the ring and spade terminals will fit into their PID locations before fastening them on. See the wiring diagram for details.
Pull on the wire and attached electrodes to ensure they will not come loose.
Next, we use heat shrink tubing to protect wires. If tubing is not available, an easy substitution is to cover the thermostat hole in a few layers of electrical tape.
Next, pull out the two wires attached to thermostat of the roaster through the hole. Attach the wires to the SSR according to the above wiring diagram.
Now, take one prepped wire with ring terminals and connect it to the roaster power wire inside the roaster. Connect the other wire with ring terminals to SSR terminal 2. Connect the other ends of these wires to the PID controller terminals 1 and 2.
It’s now time for the prepped wires with spade terminals. Use one wire to connect SSR terminal 4 to PID terminal 7, and the other to connect SSR terminal 3 to PID terminal 6.
Finally, connect the thermocouple to PID terminals 8-10 as shown in the wiring diagram.
We have found the Pt-100 sensor to be particularly sensitive to water so we put the whole thing inside a latex glove.
Lastly, we put the end of the air pump tubing into the air pump, and the other end between the tines of a fork to weigh the tube down.
The last step is to correct the thermocouple settings on the PID controller. On the PID, hit SET, enter the number 0089, and press SET again. Scroll up or down so that”Inty” is blinking, and press SET. Then scroll so that “Pt10.0″ is blinking. This lets the controller know we are using a Pt-100 and want to measure temperature to 0.1 degrees. Press SET, scroll to “End” and press SET.
And she is finished! We add water to the tub and plug everything in.