A method for controlling the epimerization of (-)-epicatechin to (-)-catechin in an epicatechin-containing product, preferably an edible product, or of (+)-catechin to (+)-epicatechin in a catechin-containing product, comprises the step of heating the product at a temperature of up to about 200.degree. C. and at a pH of up to about 8. Under either method, the epimerization may be carried out in an open food processor in a reduced oxygen atmosphere or in a closed food processor. The edible product may be pasteurized, boiled, or sterilized during the epimerization. Epimerization is minimized by lowering the heating temperature, by lowering the pH, and/or by lowering the heating time. Conversely, the epimerization is maximized by increasing the heating temperature, by increasing the pH, and/or by increasing the heating time. The edible product may contain or be a fruit product, a vegetable product, a cereal product, a bean product, a nut product, a spice product, or a botanical product.