The yogurt worked

I did it! I made my own yogurt! Last night, around 7PM, I heated up a small pot of milk to just before the boiling point. I poured it in a jar and let it cool until about 9:30PM on the counter, then added about 1/4 cup of plain yogurt. I put the tightly sealed jar in a large pot with hot tap water, up to about 1/4 of the way up the side of the jar. I put the cover on the pot, covered the pot with a couple of dishtowels and wrapped the sides of the pot with a bath towel, to keep some heat in. This morning, at 6:30 when we got up, I checked the jar: it was full of firm yogurt! I put the jar in the fridge and tested it for flavor a few minutes ago. Yum. Good to know. I'll just have to keep it up, making a fresh batch every 5 days so that the cultures stay active.