Digester process management involves carefully balancing the quality and quantity of sludge going into the digester and the health of the micro-organisms—an imbalance can result in a poor quality or quantity of biogas production (too much or too little), a digester upset or foaming. Monitoring biogas production is a complex endeavor. Not only is it affected by the sludge and micro-organisms, but as a condensing gas, daily and seasonal temperature variations also change the amount of liquid present in the biogas.