TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first light metal cation is magnesium, the second light metal cation is calcium, the third light metal cation is sodium, and the fourth light metal cation is potassium. Preferred Method: The step of establishing baseline concentrations of the at least four light metal cations in the organic material comprises: adding the light metal cations to the organic material as metal hydroxides or soluble oxides to raise the pH of the organic material to 5.4; adding a mixture of the light metal cations to the organic material as metal carbonates to raise the pH of the organic material to 6.6; adding a mixture of the light metal cations to the organic material as metal bicarbonates to maintain the pH of the organic material at about 6.6. The step of adjusting the pH of the organic material comprises: adjusting the pH of the organic material at least one times by a predetermined amount by modifying the amount of light metal cations present in the organic material as metal bases to identify an optimal pH of the organic material, the optimal pH yielding a maximum methane production rate from the organic material. The step of adjusting the alkalinity of the organic material comprises: measuring a first alkalinity of the organic material and a first methane production rate of the organic material; adding the light metal cations to the organic material as a combination of metal hydroxides and metal bicarbonates, while maintaining the pH of the organic material constant; measuring a second alkalinity of the organic material and a second methane production rate of the organic material; adding the light metal cations to the organic material as metal carbonates, while maintaining the pH of the organic material constant; measuring a third alkalinity of the organic material and a third methane production rate of the organic material; and determining the optimal alkalinity of the organic material, the optimal alkalinity consisting of the alkalinity relating to the highest of the first, second, or third methane production rates. The baseline concentrations of the at least four light metal cations comprises sodium (20 mM), potassium (7 mM), calcium (7 mM), and magnesium (5 mM). The step of adjusting proportions of the light metal cations comprises: adjusting the ratio of divalent to monovalent cations in the organic material at least one times to identify an optimal ratio, the optimal ratio yielding the maximum methane production rate of the organic material; maintaining the ratio of divalent to monovalent cations in the organic material at the optimal ratio; adjusting the ratio of magnesium to calcium in the organic material at least one time to identify an optimal ratio, the optimal ratio yielding the maximum methane production rate of the organic material; and adjusting the ratio of sodium to potassium in the organic material at least one time to identify an optimal ratio, the optimal ratio yielding the maximum methane production rate of the organic material. The carbon dioxide is added to the organic material. The carbon dioxide comprises carbon dioxide recycled from the organic material. Preferred Components: The optimal ratio of monovalent to divalent cations is 1000/1-1/5; sodium to potassium is 100/1-1/5; calcium to magnesium is 10/1-1/5. EXAMPLE - No suitable example is given.