In this study, we examined the carbon stable isotope ratio (δ
13C) of alcohol and the oxygen stable isotope ratio (δ
18O) of water in commercially supplied
Honkaku Shochu (
Mugi Shochu,
Imo Shochu,
Kome Shochu,
Soba Shochu,
Kokuto Shochu,
Sakekasu 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 δ
18O value of water in it at around 25% alcohol. The δ
18O values of water in
Honkaku Shochu are correlated with the latitude (R
2 = 0.67), regardless of the kind of raw materials used. The δ
13C values of alcohol in
Kokuto Shochu (–17.6±0.8‰), 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‰), is characterized by a lower δ
13C of alcohol than that has no indication of the geographical origin of barley (–24.8±1.4‰).
Imo Shochu, made from
Imo Koji (–28.4±0.2‰), is characterized by a lower δ
13C of alcohol than that from
Kome Koji (–27.8±0.4‰). These results suggest that the δ
13C values of alcohol and the δ
18O values of water in
Honkaku Shochu are partially useful for confirming the geographical and raw material origins.
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