1/2 gallon milk
1 cup plain yogurt with active cultures
[1/2 cup powdered milk if using 2% or lower milk or ultra-pasteurized milk]

Pour milk into crockpot.
Cover, turn on high and let the milk heat until almost boiling. The actual temp is 180F, 
but I don't use the thermometer.  Mine takes about 2 hours.

Turn the crockpot off. Take the lid of and let cool back down to 115F or where you can 
stick your finger in and leave it for 10 seconds.   Stir it around every once in a while 
as it's cooling.

Stir in 1 cup of plain yogurt from the store.  If you're using powdered milk, stir in now.

Put lid back on, wrap entire crockpot with a beach or bath towel and set away for 8-12 hours.   
I usually stick it in the oven--keeps it away from drafts and it will retain some more of 
the heat longer.

Stir it up and put it in your containers.
Remember to freeze some of it in 1 cup portions (this first batch that has been cultured 
from store bought yogurt) for your next batch!