TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process further involves processing the biogas to obtain methane at greater than 95% purity. Greater than 50%, 60%, 70%, 80% or 90% of the solids (on a wt of liquid/dry wt of solids basis) of the slurry has been derived from a material comprising spent cereal and yeast in a ratio of 3:1-1:3. The slurry further comprises silage in an amount of up to 20% of the total solids on a dry basis; initially comprises a dry solids content of up to 20% on a wt./wt. basis, up to 15%, up to 12%, or up to 10%; and comprises spent pot ale, pot ale syrup, water and/or a liquid which possesses a high buffering capacity for maintaining the anaerobic digester at the desired pH. The liquid with a high buffering capacity for maintaining the anaerobic digester at the desired pH possesses a high bicarbonate alkalinity. The bicarbonate alkalinity of the slurry during the process is at least 3000 mg per liter. The liquid which possesses a high buffering capacity is a liquid digestate obtained from anaerobic digestion of soluble waste products and/or a liquid digestate obtained from the process. The pH is 7-7.4. The liquid digestate is recycled to form slurry with new spent solid cereal products and/or further processed for use in agriculture. The methanogenisis comprises anaerobic digestion by mesophilic acidogenic and methanogenic bacteria at 30-40 degrees C. The anaerobic digestion has average retention time of 35-45 days. The starter culture of microorganisms for carrying out an anaerobic digestion is obtained from a waste sewage sludge treatment plant, or from a conditioned microbial population obtained from the anaerobic digestion of soluble distillery waste products. The slurry, prior to anaerobic digestion is subjected to a milling or other suitable grinding or homogenizing process to reduce the particle size, increase surface size area, and/or aid solubilization of the solids in the slurry. The process further involves monitoring at least one micronutrient level and adding the micronutrients to the anaerobic digestion process as required; and involves an acidogenic phase prior to the anaerobic digestion. The acidogenic phase has an average hydraulic retention time of only 24 hours (with no recycling). The liquid digestate is stored for a period of up to 180 days. At least a portion of the liquid digestate is subjected to evaporation to concentrate the liquid digestate such that it is suitable for use as a liquid fertilizer; and is subjected to evaporation to form a solid product suitable for use as a solid fertilizer. The portion of the biogas is used to aerate the anaerobic digester. EXAMPLE - No suitable example given.