Valley Brook Tea.

Valley Brook Tea occupies a space inside The Ven at Embassy Row, the hotel at 2015 Massachusetts Avenue NW, and says it is headquartered in Fujian and in Virginia. Its claim is unusual for a shop in an American city: it cultivates three tea mountains and grows, harvests, crafts and packages everything it sells, which it calls its three-W guarantee. The range follows from that, concentrating on oolong, black and white tea from one province rather than ranging across the tea world.

The packaging decides how you buy here. Most teas come in five gram bags sold as a single sample, an eight-pack or a sixteen-pack; the Wuyi oolongs come in eight gram bags sold as a sample, a six-pack or a twelve-pack. Each bag is stated to make at least a litre of tea. That makes a single sample the cheapest honest way to try a named Fujian tea anywhere in the city, and it also means you never open more leaf than you are about to drink.

The shop is not only a shelf. It runs its own hot and chilled tea menu on site, promotes an in-store tea experience, publishes a tea blog and has hosted public tea classes; gift cards bought online are redeemable in the Dupont store. One practical warning: the site publishes no opening hours anywhere, so call before crossing town. Shipping is free above ninety-nine dollars, with up to two business days of processing.