I finally made a decent raw milk yogurt! I had the flavor I wanted, but couldn't get the consistency. I kept getting something that would properly be called a yogurt shake. The problem was that I wasn't heating the milk enough. Heat destroys the enzymes and natural good bacteria in the milk and I wanted to keep those. Otherwise, why not just use pasteurized milk? But it turns out that the milk's bacteria was competing with the starter culture! So, do you lose the benefits of using raw milk if you heat it to 180 degrees (as many yogurt recipes suggest)?

According to Linda Joyce Forristal (care of the Weston Price site):

Whatever temperature the milk will be heated to, in my opinion it is best to begin with raw milk. It is not homogenized so you get a wonderful cream on top. It has not had milk solids added to it, so it won’t stick to the bottom of the pan. Most important, raw milk has not been pasteurized, which is a violent, rapid-heating process that has a very detrimental effect on the proteins in the milk. A slow, gentle heating on your stove top will more effectively preserve the integrity of fragile milk proteins, especially if you remove the milk from the stove as soon as the desired temperature has been reached.

Here's my recipe:
1 quart of raw milk
1/4 cup of good commercial organic yogurt as a starter (I used Seven Stars)

Measure out the starter and allow to come to room temperature while heating the milk. In a saucepan, slowly bring the milk up to 180 degrees, stirring periodically (it took me one hour). Allow the milk to cool back down to 110 degrees, again stirring periodically. Put the milk and starter into jars, twist on a lid, and place in a dehydrator for 8 to 10 hours. (I did 10.) Refrigerate the jars. Since the milk had not been homogenized, there is a lovely cream line.