At Infuse Tea Bar in West Sayville on a recent evening, Kristine Henderson, 42, the owner, demonstrated the “slurp, swish and swallow” technique to six would-be aficionados. “You aerate the tea in your mouth and you coat the taste buds, so you can experience all the aromas and subtle flavors,” she said as the class sampled the first of six Japanese teas.

The 90-minute tasting workshop, one in a series of 15 workshops she has been offering on loose-leaf teas from around the world, began with an enthusiastic discussion of Japanese terroir. The growing conditions, the harvest and the drying, roasting and processing of the leaves all influence the flavor of each tea, she said.

A gyokuro tea has a buttery, vegetal aroma like corn or cut grass, Ms. Henderson said. It was followed by a three-ounce shot of powdered matcha green tea, which was bracing and smooth with a hint of seaweed.

Ms. Henderson, a certified tea specialist with accreditation from the Specialty Tea Institute in New York, is one of several owners of new establishments on Long Island who lead tea tastings and other events to introduce the variety and quality of loose-leaf teas to customers.