🍵 Tea

Tea (a cuppa, a brew) is an infusion of the dried leaves and buds of the tea plant, Camellia sinensis. White, green, yellow, oolong, black and dark tea such as pu-erh all come from this single plant; what separates them is processing. Chamomile, rooibos or linden infusions are often called tea too, yet none of them grows on the tea bush.

What counts as tea in the strict sense is set by ISO 20715:2023: the standard sorts into types only products of Camellia sinensis and keeps herbal and fruit blends outside its scope. Besides the Chinese form of the bush, black tea also draws on the Assam variety, Camellia assamica. Rooibos grows on a different plant altogether, the South African legume shrub Aspalathus linearis, so, like chamomile, it is more accurately called an infusion.

Between bush and cup lie five steps: the leaf is plucked, withered, rolled, left to oxidise and dried. The fourth step shapes the result most; how the leaf's own enzymes change its colour and taste is explained on the Tea oxidation page. In short, green tea is heated before oxidation can start (by steam in Japan, in a hot pan in China), black is taken all the way over a few hours, and oolong is halted halfway. White is barely handled, yellow is allowed to sweat, and dark tea such as ripe pu-erh matures with the help of microbes. A side-by-side view of all six groups is on the Types of tea page.

FAO statistics for 2022 count 6.7 million tonnes of tea worldwide, and more than half of that mass, 3.58 million tonnes, is black. Green trails behind but grows faster: over ten years its output rose 4.9 % annually versus 2.1 % for black; in 2020–2022 the average harvest was 2.31 million tonnes, nearly all of it (2.06 million tonnes) in China. Countries guard where their tea comes from: the best-known protected name is Darjeeling from West Bengal, whose gardens and altitudes have their own page. Japan is famous for sencha and matcha, South Africa for rooibos.

How much caffeine? The USDA table gives 20 mg per 100 g of brewed black, 16 mg for oolong and 12 mg for green; coffee measured the same way has 40 mg. Scaled to an ordinary 240 ml cup, that is about 48 and 29 mg respectively. Chamomile and rooibos have none at all. EFSA's limits for healthy adults are 200 mg at one time and 400 mg over a day, and 200 mg a day in pregnancy and while breastfeeding. Not a single health claim for tea has been approved in the EU.

Shops sell tea loose, in bags and as powder. By particle size there is whole leaf, Brokens and Fannings, which the Darjeeling specification tells apart by size alone. Black tea is made either traditionally, by twisting the leaf (orthodox), or by CTC, which tears and shreds it. Matcha is ground tencha, shaded for 20–30 days before harvest. How to check that a pack of Darjeeling or rooibos is genuine is covered on their own pages.

Appearance and taste make the types easy to tell apart: green is pale and fresh with grassy notes, black is dark and reddish, oolong fruity and floral. More on the colour of each liquor is on the Green tea and Black tea pages. Colour is also a hint about caffeine: a darker cup is usually a stronger one.

Water matters most. For black tea the British UKTIA advises water just off the boil and a few minutes of steeping, for green noticeably cooler water; Japan's ministry also caps water hardness for sencha. Exact degrees, minutes and grams are on the Black tea and Green tea pages. The general rule is simple: the hotter the water, the more bitter and strong the brew. Under ISO 3103, milk belongs in black tea only.

Every country drinks it its own way: the British have Afternoon tea, the Chinese Gongfu tea, and there is Turkish tea and East Frisian tea culture. Why this matters to you: once you know the type and the right water temperature, the same pack gives you less bitterness and a predictable dose of caffeine.