Pour a 1/2 - whole gallon whole milk into crockpot on high heat for approximately 2-3 hours-until it reaches 180 degrees.
Turn off and allow to cool for approximately 3 hours-until it reaches 120 degrees.
Take out 2 cups and add in 1/2-1 cup of your cultures to it, then pour back into crockpot, mix well, cover, wrap with a towel and let sit for 6-8 hours.
Refrigerate for 12 hours. You may strain out some whey if you would like a thicker consistency yogurt. Remember to save a cup of yogurt for your next batch.