As it happens, there is a document reprinted in Benjamin Labree’s The Boston Tea Party, 1773, which details the exact composition of the crates of tea that were dumped into Boston Harbor in December 1773. The official report, filed in February 1774, lists the following: out of 340 crates carried on the Dartmouth, Eleanor and Beaver, 240 contained Bohea, 215 were Congou, 10 were Souchong, 60 were Singlo, and 15 were Hyson.

So what exactly were these varieties of tea? Even though the tea monopoly belonged to the East India Company, all the tea leaves were imported from China. While the Chinese themselves had a sophisticated system of classifying tea – defining tea varieties primarily on the place of origin, as well as by mode of preparation and quality of the leaves – English merchants had a cruder method of defining tea by color and appearance.

In the early years of the tea trade, dominated by the Dutch, green teas dominated, but by the mid-18th century the Dutch had innovated methods of exporting a kind of black tea commonly known as Bohea, which was a cheap, low-quality variety that allowed tea-drinking to become popular in both Europe and among American colonists.

The tea took its name from the Wuyi mountains between Fujian and Hokkien province; “Bohea” was the English pronunciation of the Fujianese word. The superior grade of Bohea, also from the Fujian area, was known as Congou, derived from the word kung fu, meaning “skill”. By the 19th century, this variety became the basis of English breakfast tea.

Souchong was another high-grade black tea variety from the Wuyi mountains, often made by roasting leaves in a bamboo basket. The word simply meant “variety of leaf”.

Singlo and Hyson were varieties of green tea, grown in the Anhui province. Hyson was possibly named after Philip Hyson, director the East India Company, although a high-quality variety picked in the spring was known as yu-tsien, meaning “before the rains”.

Singlo was also a green tea, with larger leaves than Hyson, which was typically picked later in the seaon. According to this 1813 source, Singlo was “more dusty than Hyson tea… twice tossed in baskets: Hyson only once.”

For more on the 18th-century tea trade, see Chris Nierstrasz, Rivalry for Trade in Tea and Textiles: The English and Dutch East India companies (1700–1800); Markman Ellis, ed., Tea and the Tea-Table in Eighteenth-Century England