Microbes need water to work and air to work cleanly. ICAR-DMR wets straw to about 75 percent moisture, roughly 4000 litres per tonne. Too wet and the heap turns anaerobic and sour; too dry and it never heats. Straw should be fresh, chopped 5 to 8 cm, and a batch under 300 kg will not hold heat.
Gypsum, added at the third turning, keeps the compost open rather than greasy and buffers the pH. Finished compost should sit at pH 7.2 to 7.8. Outside that band growth slows and white plaster mould invades, and a low pH favours green mould.