F. This is the pile temperature when you first build it. The psychrophylic bacteria begin to decompose the pile by breaking down the particles. If there is enough air, moisture, and food in a pile in this temperature range, the phychrophilic bacteria will be very happy. When bacteria are happy, they eat and reproduce. Reproduction occurs by literally splitting themselves in half down the middle and becoming two bacteria.
Bacteria reproduce at amazing speed.
One gram of Escherichia coli in favorable conditions takes only three hours to become a pound. This amazing rate of reproduction, in addition to the eating frenzy which occurs, builds heat. If the compost pile is a minimum of 3 x 3 x 3 feet, the center of the pile will retain the heat that is generated. If the pile is smaller, the heat will escape into the air and the pile remains cool. Mass is one of the variables we control by building piles of at least 1 cubic yard.