Now this is the hard part. You must leave your pot of milk/starter undisturbed for at least 7 hours. The longer you let it go the tangier your yogurt will be. Be careful when checking the temp in your roaster not to disturb the pot. That means no peaking under the lid! You don’t want to jiggle the pot at all. Leave it alone and periodically check the temp in side the roaster. Adjust as needed.