The brewing process is different. Japanese sake is a fermented wine, while Japanese sweet potato shochu is a distilled wine. Its alcohol content is higher than that of sake, usually between 20 and 30 degrees. Of course, there are also higher alcohols. The production process of Japanese shochu is generally divided into two types, namely continuous distillation and single distillation. Purine is a substance produced by microbial metabolism. Distilled sweet potato soju does not contain microorganisms, so there is no purine.