I use whole milk I buy at Aldi. First step is to heat it to 180°F, which I do in the microwave in a glass measuring cup. I usually do 2 quarts and microwaving it for 11 minutes covered gets me the temp I want. This step is optional, but alters the proteins and makes a thicker yogurt.

Next I cool the milk down to 110°F. Sometimes I use a mason jar filled with ice water to do this more quickly than just standing the milk at room temperature. But milk at over 115° or so will kill the culture, so this is important. I check with a couple thermometers, one infrared and one instant-read pen type. But you can comfortably touch 110 degree liquid, so you can get away without the thermometer at all.

I add about two tablespoons of the freshest commercial yogurt I can obtain as a culture starter. I really like Fage, but I’ve had good luck with other brands. IF you like the taste of the yogurt, using it as a starter should be fine, just avoid flavored and sweetened starters.

I have some five-pound cartons that I bought filled with yogurt originally–these make great containers to do the actual culture. My method is to put the yogurt in this container, then cover it and place it in a metal stock pot that I fill with hot tap water, which gets me to about 110 degrees without much effort.

That pot goes into my oven, and by using a combination of the bread proofing setting and leaving the oven light on, I keep the yogurt over 100 degrees overnight. In the morning I have excellent, fresh yogurt.

To get Greek style yogurt, I sometimes strain the whey out. I have muslin bags, but I also like a plastic fine mesh strainer that I got at a thrift store. Straining can really thicken the yogurt up and make it tastier and more nutritious per gram.

I keep my yogurt in mason jars with a date label made from freezer tape (date written in sharpie marker). If you eat a lot of yogurt, paying six or seven bucks for the five pound tubs seems good until you figure out how to get a fresher homemade version for around two bucks.