$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.

Shopping list:

  • 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

I prep some wires while Yoav disassembles the roaster.

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.

Our original two wire prep, one with ring terminals and the other with spade terminals.

We use heat shrink tubing to protect the wires leaving the roaster.

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.

Wiring diagram.

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.

Feed a power wire and heating wire through the thermostat hole.

Attach power wires to the relay, but keep relay loose for now.

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 setup in water, with the sensor in a glove on the left and the tubing in a fork on the right.

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.

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17 Responses to “$100 DIY cheese vat/sous vide circulating water oven”

  1. @Yoav Perry
    January 11, 2011 at 3:10 pm #

    The hacking continues. First of, just to note that the ceramic coated wire that is the end of the heating element is no longer going directly into the SSR because, well …it’s hot! Instead I just connected it to a ceramic terminal (you know, those cheap $0.39 cent ones from a hardware store) and then transferred the power to a more manageable wire, the heat resistant type ($0,69 cents per ft at a hardware/lighting store or Radio Shack). It’s better for the wire, it’s safer design that contains the heat in the insulated body of the roaster, and it protects the SSR from unwanted heat.

    The duct tape is only for testing purposes and not a suggested design… I am now on to finish this project by getting a nice stainless steel or plastic box to mount the electronics into in a safe sturdy way. This will be screwed on to the body of the roaster and sealed with a silicone ring so it will be a safe, elegant nice finish. Will send photos in when done …or, will we be making cheese together in this thing soon?

    • January 11, 2011 at 4:00 pm #

      Om nom, it has to be goat cheese… we’re both lactose intolerant!! Yoav! I’m so excited to see the finished product!

  2. January 12, 2011 at 9:45 pm #

    something about this is so cool, but i literally have no idea what’s going on here — totally baffled

    • January 13, 2011 at 1:19 pm #

      My offer stands to debaffle you. Buy parts, we’ll put it together for you. :-)

  3. Paul
    January 23, 2011 at 1:47 pm #

    Howdy Yoav, Abe and Lisa…first of all, thanks for such a great idea; wonderful blogsite.

    Now…I didn’t blow up. But on a slight mod, something is awry. (Please see ). If around, and have the time, your thoughts very much appreciated!

    Best, and thanks again,


  4. Paul
    January 23, 2011 at 1:48 pm #

    sorry, messed the link up.

  5. Matt
    March 28, 2011 at 2:47 pm #

    After much research I think that your solution for either an external universal controller or this water oven setup would be the best setup for what me and the wife are seeking.

    We want a setup that has the pull out and plug in elegance of the sous-vide supreme with out the cost.

    After reading this post I think this would be easiest solution that could be wired to pull out and plug in. With that in mind what do you think?

    The $50 sous-vide and the $70 universal controller may be cheaper but I think the savings is negated by the setup and storage of the device. Especially if you crafted a permanent box instead of duct tape for the device.

    Does this perform as well as your other sous vide machines?

    Thanks in advance for the advice and love the blog.

    • April 2, 2011 at 12:58 pm #

      Thanks for your comments! Yoav seems happy with this design, but I have heard that designs with the heating element below the water (rather than on the sides) work a little better, so if you can you should get a rice cooker instead. If you have room, and don’t mind less portability, this is definitely easier to pull out and turn on than the other systems. It should be just as stable, etc.

  6. November 8, 2011 at 6:01 am #

    I am ready to do this……but I am skeptical of the roaster being used. Does that thing really fit 22 quarts of liquid? I am really looking to make 4 gallon batches (16 quarts). It it doesn’t I was thinking of using the same set-up, but with an electric steam table/warming well. Thoughts?

    • November 10, 2011 at 11:21 am #

      Yep, it fits 22 quarts, but you need to use it as a double-boiler for making cheese, since there needs to be circulation from the walls. So how much cheese you can make will depend on what you use as the inner container.

  7. Mark
    January 24, 2012 at 4:34 am #

    Hello, thank you for your work on this site–I have really enjoyed studying your DIY designs here. I am still new to PID, but I have a question. My application will be not sous vide but aerobic fermentation, specifically natto, which must be kept at around 40 degrees C for up to 24 hours to complete. I think PID control is perfect for this. I would have the natto (made from soybeans) in a shallow container, about 1 kg at a time, and use the PID to control a water bath. Do you think the design here would be adequate for that?

    • January 24, 2012 at 9:15 am #

      Hi Mark,

      This should be great for that. Yoav used it for cheese, usually only for a few hours, but the temperature should be stable for arbitrarily long.

      If you’re handy with soldering, we’re coming out with a new Ember Kit next week that will fit onto this type of roaster.

      Good luck!

  8. John O
    June 8, 2012 at 12:03 pm #

    Quick Q:

    Why did you choose to bypass the thermostat? I’m looking into a similar build and it makes more sense to me to just build a generic “box” that I can plug any appliance into with the relay controlling power to the box’s “out” plug.

    I figure this way I can control (with recalibration each time) not just the roaster, but also crock-pots, electric smokers, etc.

    Was there something about this roaster that wouldn’t let you do this?


  9. Tom Turophile
    December 3, 2012 at 12:07 pm #

    With Christmas and Modernist Cuisine at Home coming, I must have a sous vide machine — not to mention that my cheesepress is almost complete.

    This setup seems good for the initial ripening stage, but will the airhose be adequate for stirring curds?


  1. $70 DIY Sous Vide Universal Controller | Q and Abe - February 21, 2011

    […] One thing we noticed is that the Pt100 probe gives some wonky results if the back end gets even a little wet, we wrapped it up in duct tape and electrical tape to avert this.  Perhaps a better idea is to put the entire probe inside a finger of a latex glove, as we did in the DIY cheese vat. […]

  2. Women 2.0 » Open Source Yumminess: DIY Sous Vide Arduino-Based Kits from Lisa Qiu of Lower East Kitchen - August 30, 2011

    […] We just want to help other people cook sous vide and to collaborate with those that are on the same wavelength. When we started in Manhattan six months ago we went to the apartment of a cheesemaker who tweeted at us and helped him make a digital cheese vat. […]

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