The muscatel character in Darjeeling tea is caused by the green leafhopper, Empoasca onukii Matsuda — a tiny sap-sucking insect that feeds on the underside of tea leaves during the warmer months. When it punctures a cell wall to extract plant fluids, the plant mounts a chemical defence. This stress response converts fatty acids and carotenoids into volatile organic compounds — the plant's attempt to repel the insect. As a by-product, it also produces the distinctive muscatel aroma.
“The muscatel note is not something the plant makes on purpose. It is a defence. The beauty is entirely accidental.
— Rohan Mehta, Head of Sourcing
The key compound is hotrienol (3,7-dimethyl-1,5,7-octatrien-3-ol), with supporting contributions from linalool, geraniol, alpha-farnesene, nerolidol, and benzyl nitrile. Together, these create the grape-like, floral quality that Darjeeling second flush is known for worldwide.
Muscatel is exclusively a second flush phenomenon — May to June, not the first flush of March and April that most people associate with Darjeeling. The leafhopper population is low in cooler months; it rises with the heat of late spring. By the time second flush leaves are ready, the insect pressure is at its peak. This is why first flush Darjeeling is delicate and greenish, while second flush is fuller and unmistakably muscatel-forward.
The effect is most pronounced at elevations between 1,200 and 2,000 metres. Estates like Castleton (ranging up to 2,300m), Gopaldhara (1,700–2,134m), and Singell occupy this ideal zone. The high-altitude plant already carries an elevated terpene baseline; the leafhopper's stress signal amplifies it dramatically.
What is remarkable is that this flavour cannot be manufactured. No pesticide-treated estate produces muscatel. When you eliminate the insect, you eliminate the note. The leafhopper is not a pest here. It is a collaborator.