Preliminary detection method for added rice- and sugarcane-derived brewer’s alcohol in bulk samples of sake by measurement of hydrogen, oxygen, and carbon isotopes

Abstract

The δD and δ18O of sake without ethanol extraction as well as the δ13C of ethanol were determined in order to detect rice-derived brewer’s alcohol. Brewing tests demonstrated that the δD decreases upon addition of brewer’s alcohol (both rice- and sugarcane-derived), while the δ18O has little response to either, and the δ13C increases only for added sugarcane-derived alcohol.

Compound Specific Carbon Isotope Analysis in Sake by LC/IRMS and Brewers’ Alcohol Proportion

“…Table 1 shows the δ 13 C values obtained for bulk sake, ethanol, glucose, and the differences between the components for 40 sake samples. For Junmai, previously reported δ 13 C values for δ 13 C bulk in sake have been −27.36 ± 0.67‰ 36 , −27.86 ± 0.22‰ 16 , and −27.8‰ 15 . The only previously reported δ 13 C glu has been −26.1 ± 0.4‰ 14 .…”

“…For example, measurements have been made of the δ 13 C of wine 7–11 , beer 12,13 , sake 14–16 , brandies 17,18 , tequila 19 , liqueur 20 , whisky 21 , and shochu 16,22 . Bulk analyses of the δ 13 C of sake have produced values of −27.8‰ 15 and −20.6‰ (−20.9 to −20.3‰) 5 . However, it is difficult to detect the addition of sugar to sake by bulk analysis.…”

Stable Isotope Analysis of Hydrogen and Oxygen in a Traditional Japanese Alcoholic Beverage, Sake, from Niigata Prefecture in Japan and Other Countries

“…In 2014, 16316 kL of sake was exported from Japan, which is approximately twice the amount of sake exported 10 years ago. 3 Notably, a specific type of sake called Junmai-shu (made from rice, koji, and water without the addition of alcohol) has expanded the foreign export market of sake; 4,5 however, this market expansion has increased the risk of distribution of counterfeit goods. 6,7 For example, in the case of Scotch whisky, several imitations have already been discovered.…”