Thomas Jefferson's financial records and correspondence show consistent purchases of tea and provide valuable information about the kinds and amounts of tea he and his family drank. The few references from the 1770s and 1780s show a variety of different kinds of tea, while in 1790-91 in Philadelphia Jefferson seems to have preferred Imperial. Hyson, especially "young hyson," is also mentioned as a favorite. No references to a specific type of tea exist in Jefferson's Memorandum Books after 1794.
1791 March 8. (Philadelphia) "Tea out. The pound has lasted exactly 7. weeks, used 6 times a week. This is 8/21 or .4 of an oz. a time, for a single person. A pound of tea making 126. cups costs 2.D."
1794 October 9. (Jefferson to John Barnes, a Philadelphia tea merchant and grocer) "Having occasion for about 20. lb. of good tea annually, I think it best to rely for the choice of price, and on no one do I rely more willingly than on yourself. I usually send to Philadelphia for my groceries once a quarter, and will on those occasions ask of you a quarter's supply of tea. At present I will beg the favor of you to pack for me in a cannister 5. lb. of good tea. Young hyson we prefer both for flavor and strength, but if you have none good, let it be hyson of the antient kind."