I have a really easy answer: drink what you like. Enough said.
In my case, I drink both. But read on to learn more.

First off, I congratulate you for asking this question. It means that you’re already drinking tea, which means you’re living—or beginning—a healthy lifestyle. Even if coffee and soda are still part of your life, the more you switch these other beverages out for tea, the better off you’ll be.

Fresh Air

The key difference between green and black tea is oxidation. Green tea is slightly oxidized, and black tea is almost completely oxidized. I know this term may scare some, especially if you’re not a science type. But it’s really quite simple, and we experience it every day.

Think of when you cut an apple. Within a short period of time, the white flesh starts to turn brown. That brownness results from a chain reaction of oxygen mixing with the enzymes that naturally occur in fruit. The only way to stop the oxidation is to heat the apple, which kills the enzymes and stops this chain reaction. This is why a raw apple turns brown and a baked apple stays white.

Hedge Clippers

The enzymes that naturally exist in fruit exist in all plants, including the tealeaf. And Chinese tea comes from an evergreen plant called the camellia sinensis. It’s more like a bush, but if left to its own devices, can grow to be 30 feet tall.

There are three main camellia varieties, and numerous sub-varieties. When farmers cultivate a sub-variety, it’s known as a cultivar. In the world of Chinese tea, we are basically drinking some form or another of the camellia sinensis. They are usually cut to waist height, as it makes for easier picking.

So what’s picked? Think of leafy shrubs in gardens or maybe even in front of your house. In colder climates, these shrubs go dormant in the winter, but in the spring, little buds start to push forth. If left alone, the buds become leaves, then one leaf and a bud, then two leaves and a bud, and on and on until the autumn when the growing season ends.

With ornamental shrubbery, at some point during the spring, we just chop off the new growth. This way the shrubs stay flat and fill out on the inside. Nobody likes to see unruly shrubbery with spindly branches sticking out all over the place.

With tea, however, these leaves and buds are plucked. If it's a finer tea, they’re hand picked, one by one. As soon as these leaves are separated from the plant, they’ll start to oxidize just like a cut apple.

From here, the farmers have to move quickly, as if we don’t start to process the leaves soon, they’ll dry out and disintegrate.

The Heat Is On

For this reason, tea-processing facilities are very close to the tea fields. Unlike fruit, which can be picked and then processed miles away and days later, tea must be processed right on the spot. There’s very little wiggle room, so often the tea is plucked by day and processed by night.

Green tea is only slightly oxidized, and black tea is nearly fully oxidized, before heating. And hence green tea is green, and black tea is, well, a really dark brown. In China, black tea is known as red tea. Over the years the “red” got lost in translation, so in English, red tea is called black tea. I have never understood why black tea isn’t known as brown tea—either in China or in the West, as that’s really what color it is.

It’s important to note that green tea and black tea are not fermented. There are no living microbes in these teas to keep them alive, and no yeast is used in the processing. Wine is made from fermenting grapes, and sauerkraut is made from fermenting cabbage, but green and black teas are made from oxidizing and then heating tealeaves.

Royal Flush

The first round of plucking is referred to as the first flush. Once plucked, new growth begins and becomes the second flush. Each new round is another flush. In China, the first flush is usually picked when the new growth begins in March, and with most teas, the final flush is plucked in the early summer.

Some farmers produce green and black tea with leaves from the very same bush, depending on the weather and market conditions in any given year.  Farmers can, say, make green tea with the first flush and black tea from the third flush. It’s just a question of processing—and how much the leaf is oxidized.

This is very different from wine. You can’t produce a cabernet sauvignon and a sauvignon blanc from fruit of the same vine. They’re different grapes, and it would be false advertising to sell one as the other. Not so with tea, which is not as commonly sold according to the varietals.

Take It Away

With some basic science under your belt, you now know that the key difference between green and black teas is oxidation.

• Oxidation occurs when oxygen mixes with enzymes that naturally occur in plants.
• Oxidation is halted when the leaf is heated, killing the enzymes.
• Green tea is slightly oxidized, and black tea is fully oxidized, before heating.
• Chinese tea comes from the same plant, the camellia sinensis.
• The tea-growing season starts in early spring and runs until the summer, with each round of picking known as a flush.

You’re now armed with correct information. You can fight back the next time someone tells you black tea is fermented. There’s a lot of bad information on the market, much of which is propagated by misinformed tea vendors and crafty advertisers. So, what works for you, green or black?