1. Pour your milk into a heavy bottom pot, and heat on medium. You want to watch closely and take temperature often, to make sure it does not boil. If you want to add sweetener or vanilla, do that now.
2. For Goat's Milk heat to 190-195 F, when milk is at 190 F, turn heat down to low and keep milk between 190 and 195 F, for about 15 minutes. If you are using Cow's Milk heat milk to 185 F and then it can be immediately cooled off - it doesn't require being held at the high temperature for an extended period of time.
3. Once milk has been heated, remove from heat and cool temperature to 120F. You can do this by just letting it sit and come down on its own, or to hurry up the process, you can put it in a cool water bath in the kitchen sink.
4. When temperature reaches 120F, add your starter culture- either freeze dried or previously made yogurt, and whisk really really well.
5. Pour into jars.
6. Incubate at around 108F for about 10-12 hours. I use my dehydrator, with the trays pulled out, set at 108F for 12 hours. You can use a cooler with warm water (115F), or even the oven with your light on, with some towels around the jars.
7. When incubation is done, refrigerate for 2-3 hours and enjoy!