Make Volume 25 Arduino-Controlled Yogurt

MAKE Volume 25 contributing writer Chris Reilly loves yogurt but is impatient. He writes, “My impatience often leads me to botch important steps when I make yogurt. So to get better control over the fermentation process, I made a crockpot thermostat attachment to precisely control the temperature.” Enter the Arduino microcontroller. From the introduction:

You can buy electric yogurt makers, but most of them only incubate; the heating/sterilization step still has to be done on the stovetop. I wanted to experiment with Arduino microcontroller programming and electronic circuit design in Fritzing (an open source circuit layout tool that lets users document and share designs), so why not combine them into something I enjoy doing?

With my old-school yogurt recipe (adapted from, I’d use a stovetop and a candy thermometer to heat the milk to 185°F and cool it to 110°F, then use a warm oven or radiator to ferment it at 100°F. That takes a lot of attention, and more containers than I care to wash later. Even with a commercial yogurt maker, I’d probably have to heat the milk myself, and that’s the step I’m most likely to botch.

Don’t get me wrong — it’s a great recipe as long as you’re diligent. But the combination of boring, time-consuming, temperature-sensitive steps puts my diligence to the test; that’s why the automation of an Arduino-controlled crockpot yogurt maker makes perfect sense to me.

Time to geek out on your fermentation process, and you can get started right away building your own Yobot by checking out the entire project on Make: Projects. If Arduino sparks your interest, MAKE Volume 25 features a ton more Arduino projects, from getting you started picking out the right microcontroller to making your own Arduino.

Make Volume 25 Arduino-Controlled Yogurt Maker Yogurt

Check out MAKE Volume 25:
MAKE Volume 25: Arduino Revolution
Give your gadgets a brain! Previously out of reach for the do-it-yourselfer, the tiny computers called microcontrollers are now so cheap and easy to use that anyone can make their stuff smart. With a microcontroller, your gadget can sense the environment, talk to the internet or other hardware, and make things happen in the real world by controlling motors, lights, or any electronic device.