This study determined the properties of Earl Grey Japanese black tea, called wakocha or jikocha in Japanese. Wakocha Earl Grey samples were as follows: “Aun” Earl Grey from Shimanto-cho in Kochi prefecture; “Ureshino” Earl Grey from Saga City in Saga prefecture; and “Sashima” Earl Grey from Sashima-gun in Ibaraki prefecture. We determined the content of essential oil and theaflavins in Earl Grey wakocha and the active oxygen-scavending function (SOD). We compared these results with those for nine other varieties of Earl Grey from around the world. The essential oil level of Aun which ranked second among the 12 tea samples, was around twice that of Ureshino and Sashima. The theaflavin content of the three Earl Grey wakocha samples ranked in the mid range of all tea samples. The caffeine level of all samples ranged from 2.10 to 2.98 mg per 100 g of tea leaf. The activity of SOD was higher in Aun than in Ureshino and Sashima. Enantiomer analysis of linalool was determined in order to verify the authenticity of the bergamot peel oil used to flavor the tea leaves. The purity of genuine bergamot oil was more than 99% enantiomeric excess of (R) (-)-linalool, the highest concentration, while the purity of (R)-(-)-linalool in other citrus oils was less than 96%ee; hence among the Earl Grey flavoring materials, it is possible to distinguish genuine bergamot oil from artificially blended bergamot oil. This analysis provided substantial evidence that the following Earl Grey varieties were flavored using genuine bergamot oil, Aun and Ureshino, and Sashima, Nittoh, Mariage. Wedgwood and Fortnum & Mason were also in this category.
