Yogurt is easy to make, and making it yourself can save a lot of money. Essentially a gallon of milk would make a gallon of yogurt. (Think $2 for the milk plus maybe .50 cents for add-ins. That's the same as paying for only a quart of yogurt, if it's on sale).
There are several methods of making it, but they all involve the same science. In a nut-shell he's what to do, and I'll also post the recipe I used on this blog.
1. Heat milk to 185 degrees (to prepare milk proteins).
2. Let milk come down to 110 degrees (the temp that yogurt bacterias can multiply).
3. Pitch the yogurt (add a little yogurt with active cultures that will then multiply through the milk).
4. Let it set for 7-8 hours or overnight keeping the temperature at 110 (the longer you let it ferment, the thicker & tangier the yogurt will be).
That's pretty much it, but there are some other tips that will make the yogurt even better. For example, the yogurt will be pretty runny. If you'd like it thicker you can add powdered milk when you pitch. After it's fermented, you can let it sit in the fridge for several hours to thicken. You can also strain it through a coffee filter or cheesecloth over a colander. The liquid that drains out is whey, which can be used in other cooking or tossed. (I happened to make bread with mine -replacing the milk with the whey- and I was very happy with the result.)
You can flavor the yogurt with just about anything--honey, fruit puree, jam, sugar. To ease my family into homemade yogurt (it's definitely not go-gurt), I added a little instant vanilla pudding powder. It thickened and sweetened without losing the tang. I figure after a couple goes with that, they'll be ready for a little more authentic taste.
When you pitch your milk, be aware that different store-bought yogurts have different numbers of active cultures. Yoplait and Dannon contain two, some store-brands zero, Stoneyfield has six. The yogurt you make will only multiply the original bacterias you put in. Keep a little of your homemade yogurt each time because you can use that to pitch the next batch.
Finally, there are several methods to heat the milk (stove-top, hot chocolate maker, crock-pot) and several methods to keep the milk at 110 degrees (heating pad, oven's pilot light, thick towel around crock pot, dehydrator). There are also yogurt makers out there that will do everything for you.
I used a crock pot method, which was nice because I didn't have to move my pot around a lot, but it did add about 4 hours of time (waiting for the milk to heat & then cool to 110). There are definitely quicker methods out there, although all will need the 8 or so hours to ferment..
So those are the basics. I found a lot of information on-line, and you all had great suggestions. Thanks especially to Mimi and Rachele! I also really liked
this site to understand what was happening during each step.
I'd love to know who has made yogurt & how you did it!