Patent ID: 8703155

Claim:
A method of producing reduced coenzyme Q 10 crystal which comprises the steps of: providing a reduced coenzyme Q 10 ; successively crystallizing said reduced coenzyme Q 10 in a solvent in the presence of a citric acid or a related compound thereof and/or an ascorbic acid or a related compound thereof; and recovering said reduced coenzyme Q 10 crystal; wherein the solvent to be used is at least one species selected from the group consisting of hydrocarbons, monohydric alcohols, dihydric alcohols, trihydric alcohols, ketones, nitrogen compounds, sulfur-containing compounds and water, and the amount of the above solvents is 50% by weight or more in a whole mixture, and wherein crystallization is carried out under forced flowing at a stirring power consumption per unit volume of 0.01 kW/m 3 or more.