I’ve been making yogurt on and off for many years. Sure, it’s easier to buy it, but it’s significantly less expensive to make it yourself. And it’s easy.
Equipment:
1 gallon insulated drink container
1 large pan
thermometer is helpful, but not crucial
Ingredients:
1 gallon whole milk
1 cup live yogurt (plain yogurt, yeah?)
Method:
Heat the milk gently until it reaches scald temperature, around 180F, stirring often. You don’t want to burn it… The milk will start to form a skin on the surface. This step alters (or “denatures”) the proteins in milk to make better yogurt. Cool the milk to about 100-110F. A sink full of ice helps here, but simply waiting works too. The milk will feel quite warm on your wrist – a little hotter than you’d give to a baby. Mix in the yogurt, and put it all into the insulated container and leave overnight.
You now have a gallon of yogurt.
To make Greek yogurt out of this, line a colander with a fine clean cloth (i.e. pillowcase fabric) and pour the yogurt into it. I pull the fabric corners up to form a bag, and let the whey drain out over the sink over several hours. Removing some of the whey thickens the yogurt and removes a lot of the sour taste to which a lot of people object.