Earl Grey tea is a tea blend with a distinctive flavour and aroma derived from the addition of oil extracted from the rind of the bergamot orange, a fragrant citrus fruit.

Traditionally the term "Earl Grey" was applied only to black tea; however, today the term is used for other teas that contain oil of bergamot, or a bergamot flavour.

The Earl Grey blend is named after the 2nd Earl Grey, British Prime Minister in the 1830s and author of the Reform Bill of 1832, who reputedly received a gift, probably a diplomatic perquisite, of tea flavoured with bergamot oil, taken from bergamot, a citrus fruit typical of Southeast Asia and grown commercially in Italy.

Co2 Method

This process is technically known as super-critical fluid extraction. In the carbon dioxide method, the caffeine is stripped directly from the leafs by a highly compressed semi-liquid form of carbon dioxide. Pre-steamed leafs are soaked in a bath of super-critical carbon dioxide at a pressure of 73 to 300 atmospheres. After a thorough soaking for around ten hours, the pressure is reduced, allowing the CO2 to evaporate, or the pressurized CO2 is run through either water or charcoal filters to remove the caffeine. The carbon dioxide is then used on another batch of leafs. This liquid works better than water because it is kept in super-critical state near the transition from liquid to gas, combining favorable diffusivity properties of the gas with increased density of a liquid. This process has the advantage that it avoids the use of potentially harmful substances.