What's the Difference Between Green, Black, Oolong and White Tea?

Most people know two teas: green, and the one in the bag.

White, green, oolong and black tea all come from the same plant, Camellia sinensis. What makes them different is what happens to the leaf after it's picked. The biggest distinction is oxidation, a series of chemical reactions that change the leaf's flavor, aroma and color.

Green tea is heated early to limit oxidation. Oolong is allowed to oxidize partway. Black tea undergoes extensive oxidation, while white tea is usually withered and dried with comparatively little intervention.

That's the short answer. The longer one is more interesting, because oxidation isn't the only decision the tea maker makes. How the leaves are grown, handled, heated and dried matters too. Those choices explain why four teas from the same plant can taste like four completely different things.

The four at a glance.

These are general starting points for brewing loose-leaf tea in an ordinary mug or pot, using about 8 ounces of water. Individual teas may prefer something different, so follow specific instructions from the producer when they're available.

For any of the four, 2–3 grams of leaf per 8 ounces of water is a sensible place to start. Some delicate Japanese greens prefer cooler water, while certain white teas and roasted oolongs take much hotter water than the table suggests.

It's worth weighing the leaves at least once. Two grams of tightly rolled oolong might fit into a small spoon, while the same weight of fluffy white tea can fill a tablespoon or more. The scoop hasn't changed. The amount of tea in it has.

There's no caffeine ranking in the table, deliberately. The kind of tea tells you less about the caffeine in your cup than most charts suggest. We'll get to that.

What oxidation does to a tea leaf.

Cut an apple and leave it on the counter, and the exposed flesh starts turning brown. Tea oxidation works through some of the same chemistry, though the process inside a tea leaf is more complicated.

Fresh leaves contain natural enzymes and compounds that can react when their cells are disrupted and exposed to oxygen. During tea making, withering, bruising and rolling help determine how those reactions proceed. Heating the leaf can deactivate the enzymes and largely stop that stage of oxidation.

Green tea is heated early, preserving much of the leaf's original chemical character. Black tea is handled to encourage extensive oxidation, transforming many of its catechins into other compounds that contribute color, body and briskness. Oolong sits somewhere between those approaches.

White tea takes a different route. It's generally withered and dried without the deliberate early heating used to make green tea. Some oxidation can take place as the leaf slowly loses moisture.

But processing isn't a single dial marked green at one end and black at the other. Roasting, drying, leaf shape, growing conditions and plant variety all influence the result. Two teas in the same category can taste further apart than two teas from different ones.

A small detour before we meet the four: China traditionally recognizes six major tea categories rather than four. Yellow tea has an additional controlled yellowing step, while dark teas, including many styles of pu-erh, involve microbial changes during processing or aging.

There's also a naming complication. What English speakers call black tea is known in Chinese as hong cha, or red tea, after the reddish color of the infusion. Hei cha, literally dark or black tea, refers to a different family. The leaves are complicated enough without the languages disagreeing about what color they are.

White tea.

The quietest of the four, at least at first introduction.

White tea is usually made by withering and drying the leaves with relatively little handling. There's generally no vigorous rolling and no early fixing step like the one used for green tea. The result can be soft, floral and faintly sweet, sometimes with notes of hay, honey or dried fruit.

But white tea isn't one single flavor. Silver Needle, made from unopened buds, is often delicate and fragrant. Shou Mei, which contains more mature leaves, can be fuller and deeper, especially with age.

White tea is easy to underestimate because a pale cup can look unfinished even when it isn't. Start with 2–3 grams per 8 ounces of water, around 175–185°F, for three to five minutes. If the result seems thin, check the amount of leaf before leaving it in the water indefinitely.

Some white teas handle water close to boiling very well. The gentle-temperature rule is a starting point, not a test of whether you're treating the leaves respectfully.

Give it enough leaf and a little attention. Quiet doesn't mean it has nothing to say.

Green tea.

Green tea is where many people first learn that water temperature matters, usually by discovering what boiling water can do to a delicate leaf.

The defining processing step is early heating, which deactivates the enzymes responsible for much of the oxidation. This helps preserve the fresh, vegetal character associated with green tea.

For ordinary green tea, start around 160–180°F and steep for one to three minutes. A delicate Japanese tea may prefer the cooler end or even less. If your green tea has always tasted harsh, water temperature is one of the first things to check. Our guide to fixing bitter tea covers the other usual suspects.

Where the tea was made matters too. Many Japanese green teas, including sencha and gyokuro, are steamed. The results often lean grassy, savory or marine. Many Chinese greens, including Longjing, are heated in pans, producing flavors that can be nuttier or more toasted.

Gyokuro has another distinction: the plants are shaded before harvest. That changes the balance of compounds in the leaves and helps produce its pronounced savory character. It's also commonly brewed at lower temperatures than ordinary green tea.

Matcha belongs to the green tea family as well, but it's prepared differently. The leaves are ground into a fine powder and whisked into water rather than steeped and removed. You're drinking the leaf itself, which also changes the caffeine calculation.

Green tea isn't necessarily delicate in flavor. Some of it is assertively grassy or savory. It just tends to make its objections to careless brewing known rather quickly.

Oolong tea.

If you only try one new thing after reading this, make it oolong. It's the hardest of the four to summarize, which is a good reason to spend time with it.

Oolong is partially oxidized, but partially covers an enormous range. Its leaves are often withered and gently bruised or turned to encourage oxidation before the maker stops the process with heat. Some oolongs are roasted afterward, adding another entire layer of flavor.

A lightly oxidized Taiwanese high-mountain oolong can taste floral, creamy and fresh. A heavily roasted Wuyi rock oolong may be dark, mineral and rich with roasted or dried-fruit notes. Two oolongs can have less in common than an oolong and a black tea.

Buying one and deciding you don't like oolong is a little like eating one apple and deciding fruit isn't for you.

It's also an excellent category for multiple infusions. Brewed gongfu style, with plenty of leaf in a small vessel and short steeps, many oolongs can produce five or six infusions, sometimes more. The flavor changes as the tightly rolled or twisted leaves open and release different parts of their character.

That doesn't mean you need special equipment. In an ordinary mug or pot, start with 2–3 grams per 8 ounces, around 185–205°F, for three to five minutes. Light, floral oolongs may prefer cooler water; darker roasted ones often welcome more heat.

Try steeping the same leaves a second time. The result may be lighter, different, or surprisingly good. Multiple infusions aren't guaranteed, but they're well worth trying.

One leaf, several conversations. Oolong has a habit of making the pot feel smaller than it is.

Black tea.

Black tea is the one much of the West grew up on: Assam, Darjeeling, Ceylon, and the breakfast blends made from teas like them. Earl Grey usually begins with black tea too, then adds bergamot flavoring.

During processing, black tea undergoes extensive oxidation, producing a darker leaf and compounds that contribute to its reddish-brown infusion, body and brisk taste.

Assam is often malty and robust. Ceylon teas can be bright and lively. Darjeeling can be lighter, floral and far more delicate than the strong breakfast blends people associate with black tea. The category is broad enough that treating every black tea the same would be a mistake.

For a typical black tea, use water around 200–212°F and steep for three to five minutes. A robust breakfast blend usually handles near-boiling water well. A delicate Darjeeling may taste better with slightly cooler water and a shorter steep.

Strong black teas also tend to work well with milk. Their fuller flavors hold their own, and the milk softens some of the drying sensation. You don't have to add it, of course. The cup belongs to whoever is drinking it.

Which tea has the most caffeine?

Black tea often has more caffeine than green tea in an ordinary brewed cup. But the familiar ranking of black, then oolong, then green, then white is much less reliable than it looks.

For perspective, Mayo Clinic's caffeine guide lists approximately 48 milligrams for 8 ounces of brewed black tea and 29 milligrams for brewed green tea. The same amount of brewed coffee averages about 96 milligrams.

Those are useful reference values, not promises about what's in your particular mug. They also don't establish dependable averages for every white or oolong tea.

The reason is that oxidation doesn't create caffeine. Tea leaves already contain it before they're processed. The amount in a finished cup depends on the material used and how it's brewed.

The variety of tea plant matters. So do the age and type of leaves, how finely they're broken, how many grams you use, the water temperature and the steeping time. Research comparing different teas and brewing methods has found substantial variation even within the same category.

Black tea is often brewed hotter and longer than green tea, which can help explain why an ordinary cup tends to contain more caffeine. But you cannot reliably work backward from the color of a tea to its caffeine content.

White tea is a good example. Silver Needle is made from unopened buds, and young tea growth can contain relatively high concentrations of caffeine. That means a delicate-tasting white tea isn't automatically a low-caffeine tea. Neither is every cup of green tea.

Shade-grown Japanese greens such as gyokuro can also produce substantial amounts of caffeine, depending on the leaf and brewing method. Matcha deserves special attention because the powdered leaf stays in the drink. You're consuming the material rather than removing it after a steep.

One myth worth retiring: rinsing tea for thirty seconds and pouring that water away doesn't reliably decaffeinate it. Some caffeine comes out in the rinse, but a meaningful amount remains. The exact amount depends on the tea and brewing conditions.

The second steep isn't guaranteed to be low-caffeine either. It may contain less than the first, but it still contains caffeine, and the amount is difficult to predict without testing.

If you're trying to reduce your intake, using less leaf or choosing a shorter, cooler brew can reduce the amount extracted, although it changes the taste as well. If you need to avoid caffeine reliably, choose a caffeine-free herbal infusion or a clearly labeled decaffeinated product, remembering that decaf tea can still contain a little.

The useful lesson is simple: tea type gives you a clue. It doesn't give you a number.

What's actually in the cup.

Oxidation changes more than color, and some of those changes are easy to taste.

Green tea retains much of its original catechin content, compounds that can contribute bitterness and astringency. During black tea production, many catechins are transformed into other polyphenols, including theaflavins and thearubigins. These help give black tea its characteristic color, body and briskness.

Oolong occupies a broad chemical and sensory range between different processing approaches. Roasting can change its aroma dramatically, sometimes making a lightly oxidized but heavily roasted oolong taste darker than you'd expect.

Tea also contains amino acids that contribute sweetness and savory character. L-theanine is one of the best known, while compounds such as glutamate contribute directly to the umami taste found in some teas.

Shading tea plants before harvest can preserve more of certain amino acids and reduce the development of some bitter or drying compounds. That's a major part of why gyokuro and high-quality matcha can taste so unusually savory, almost like a light broth.

All of this chemistry helps explain what's in the cup. It isn't a scorecard for which tea is healthiest or best. You'll encounter plenty of confident health promises attached to tea, but the research is complicated and still developing.

None of it is a reason to drink a tea you don't enjoy.

Is herbal tea actually tea?

Not in the strict botanical sense. White, green, oolong, black, yellow and dark teas all come from Camellia sinensis. Chamomile, peppermint, rooibos and hibiscus come from other plants, so they're more precisely called herbal infusions or tisanes.

They're still perfectly good drinks. Most common herbal infusions are naturally caffeine-free, which makes them useful when you want something warm without the stimulation.

There are exceptions. Yerba mate and guayusa are botanical infusions with plenty of caffeine, so the word herbal on a label isn't a guarantee that the drink contains none.

And if you want to explore beyond the four familiar tea styles, yellow and dark teas are waiting on the same shelf, even if the shops near you don't always carry them.

Which makes the next shelf of tins a little less mysterious. White, green, oolong or black, the label tells you something about how the leaf was handled after picking. It doesn't tell you whether you'll enjoy it, how much caffeine is in your cup, or whether the most expensive tin will be your favorite.

A tea maker might spend hours or days bringing a leaf to the point where it's ready to brew. You can spare it a couple of minutes while the kettle cools.