SI medium (culture medium for detecting hiochi-kin)

SI medium (SI baichi) is a simple culture medium that plays an important role in sake brewing. It is used mainly to detect whether sake has been contaminated by hiochi-kin (火落菌), the spoilage bacteria that cause sake to deteriorate. The medium contains ingredients that promote the growth of specific microorganisms, and the presence of hiochi-kin is confirmed by observing how microorganisms introduced from the sake react in it. By using SI medium, brewers can carry out quality control of their sake, which allows problems to be detected early and countermeasures to be taken.