So far, I have fresh milk and cream, now onto yogurt. I make yogurt 1 gallon at a time. The process is fairly simple. I take one gallon of milk and place it in a soup cooker and heat it up to somewhere between 170-180 degrees.
I do not do this for pasteurization purposes, this is done for consistency. When I first started making yogurt, I was reading everything I could about the process and how different people made yogurt and the types of yogurt that can be made. Yes I'm geeky that way, but from what I learned with a layman's understanding, the heating process breaks down the milk proteins that the yogurt culture feeds on. This reaction causes the yogurt to be of consistent texture and mouth feel. This maybe right, maybe wrong, but I know it works after making several gallons of yogurt. After the milk reaches the desired temperature, I let it cool to about 100-110 degrees. I then stir in two jars of yogurt from a previous batch (shown below) and stir it in thoroughly (shown at right).
After the milk and yogurt culture is thoroughly mixed, I ladle it into half pint jars and add a ring a lid.
The jars are then placed back into the soup cooker for four hours at 110 degrees. This allows the culture to grow and eat the milk proteins and curdle the milk into yogurt. I relate the whole process to cooking a turkey. A lot of prep then wait around til it's done. The payoff. I usually end up with 19 jars of yogurt that I guess run around 7 oz. Store bought organic yogurt was 99 cents for a 6 oz serving. Take away the two starter yogurts and that's a $16.83 I didn't spend at the grocery store. You may be asking can I trust the soup cooker temp to be accurate, see below for the detailed scale of black marker settings on the thermostat. The 88 degree mark is for the mozzarella to come.