Stable Isotope Analysis of Commercially Supplied Honkaku Shochu

In this study, we examined the carbon stable isotope ratio (delta C-13) of alcohol and the oxygen stable isotope ratio (delta O-18) of water in commercially supplied Honkaku Shochu (Magi Shochu, Into Shochu, Kome Shochu, Soba Shochu, Kokuto Shochu, Sakthasu Shochu, Awamori) to confirm them as a potential index for verifying the geographical and raw material origins. The small-scale Kome Shochu brewing experiment revealed that the material water affects the delta O-18 value of water in it at around 25 % alcohol. The delta O-18 values of water in Honkaku Shochu are correlated with the latitude (R-2 = 0.67), regardless of the kind of raw materials used. The delta C-13 values of alcohol in Kokuto Shochu (-17.6 +/- 0.8 parts per thousand), made from brown sugar, are higher than those in other Honkaku Shochu, made from rice, barley, sweet potato, buckwheat, and Sake lees. Mugi Shochu, made from domestic barley (-26.2 +/- 0.8 parts per thousand), is characterized by a lower delta C-13 of alcohol than that has no indication of the geographical origin of barley (-24.8 +/- 1.4 parts per thousand). Imo Shochu, made from Imo Koji (-28.4 +/- 0.2 parts per thousand), is characterized by a lower delta C-13 of alcohol than that from Kome Koji (-27.8 +/- 0.4 parts per thousand). These results suggest that the delta C-13 values of alcohol and the delta O-18 values of water in Honkaku Shochu are partially useful for confirming the geographical and raw material origins.