accelerate their activities and as the ambient temperature increases
generate even more heat, the ultimate temperature is reached when
the pile gets so hot that even thermophilic organisms begin to die
off. Compost piles have exceeded 160 degree. You should expect the
heaps you build to exceed 140 degree and shouldn't be surprised if
they approach 150 degree

Other types of decomposing organic matter can get even hotter. For
example, haystacks commonly catch on fire because dry hay is such an
excellent insulator. If the bales in the center of a large hay stack
are just moist enough to encourage rapid bacterial decomposition,
the heat generated may increase until dryer bales on the outside
begin to smoke and then burn. Wise farmers make sure their hay is
thoroughly dry before baling and stacking it.

How hot the pile can get depends on how well the composter controls
a number of factors. These are so important that they need to be
considered in detail.

_Particle size. _Microorganisms are not capable of chewing or
mechanically attacking food. Their primary method of eating is to
secrete digestive enzymes that break down and then dissolve organic
matter. Some larger single-cell creatures can surround or envelop
and then "swallow" tiny food particles. Once inside the cell this
material is then attacked by similar digestive enzymes.

Since digestive enzymes attack only outside surfaces, the greater
the surface area the composting materials present the more rapidly
microorganisms multiply to consume the food supply. And the more
heat is created. As particle size decreases, the amount of surface