Build Your Own Yogurt Maker, Sous-vide Cooker, and All-purpose Fermenter for $40

I make a half gallon of yogurt, twice a month.  I like making my own yogurt for many reasons, but it's a bit of a pain.  Since I make large batches, I can't use a standard yogurt maker.  I often get distracted and over-heat the milk, and the method I use to incubate the yogurt is wildly inefficient (my beloved Excalibur dehydrator).  I also need a constant warm temperature for various other fermentation projects, and that's often difficult to achieve with the tools I have.

I finally found a better solution: a temperature controller that accurately regulates the temperature of a slow cooker by turning an outlet on or off.  I simply set the temperature of the controller, place the temperature probe into the slow cooker, and plug the slow cooker into the temperature controller outlet.  The slow cooker then stays at whatever temperature I want.  Here's what the temperature controller looks like:

Once built, the temperature controller with or without the slow cooker can be used for a variety of other tasks (including regulating cooling devices).  Here are some ideas that come to mind:

• Sous-vide cooker
• High-capacity yogurt maker
• Bread dough riser
• All-purpose thermophilic fermenter (e.g., for tempeh, natto, koji)
• Beer/cider/wine fermentation temperature controller
• Kegerator controller
• Freezer-to-fridge conversion
• Egg incubator
• Soil temperature controller for seed starting

Don't worry, I'm not turning into a food blogger.  But this sous-vide-cooked
chicken I made with my DIY temperature controller was pretty tasty.
I used this recipe from NomNom Paleo.

You can build the whole thing for about $40, including the slow cooker.

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