Green Tea: A Complete Overview

Green tea is the largest tea category in China by a wide margin, and it is also the easiest one to ruin. A bag that smells like sweet corn and fresh hay in March can taste like old straw by September if it sits in a warm cupboard. That instability is the whole story of the category. The leaf is picked, heated hard enough to stop the enzymes that would otherwise darken it, and then spends the rest of its life slowly losing the compounds that made it worth buying.

Almost everything below follows from that single step. Stop the enzymes and the leaf stays green. Do it badly, or store the result carelessly, and no amount of good brewing will bring the cup back.

What Actually Makes a Tea "Green"

Every true tea comes from Camellia sinensis. Green, black, oolong, white, yellow and dark teas are the same plant steered in different directions after picking. The fork in the road is a group of enzymes, polyphenol oxidase above all, that start oxidizing catechins the moment the leaf is bruised. Leave a picked leaf alone for a few hours and it darkens, and the aroma moves toward malt, dried fruit and wood. That is the road to black tea.

Green tea takes the other road. Within hours of picking, the leaf is heated hard enough to denature those enzymes, so oxidation stops before it has produced much colour or much aroma change. In Chinese this step is sha qing (杀青), usually translated as "kill-green." The translation is a little unfair: what gets killed is the enzyme, not the green.

How hot, and for how long, decides what you end up drinking:

• Pan-firing (chao qing, 炒青). Leaf goes into a heated wok or rotating drum, often starting around 180 to 220 °C and dropping as moisture leaves, for somewhere between 5 and 15 minutes depending on the batch. This is the Longjing method and the source of the toasty, nutty edge people recognise in Chinese greens.
• Steaming (zheng qing, 蒸青). Saturated steam for roughly 20 to 45 seconds for Japanese sencha; deep-steamed fukamushi styles run 60 to 120 seconds. Steaming is faster and more even than pan-firing, and it keeps more of the leaf's original colour and grassy, marine character. Enshi Yulu from Hubei is one of the few Chinese greens still made this way.
• Basket or oven baking (hong qing, 烘青). Hot air in the 100 to 130 °C band. Gentler than a wok, which is why baked greens often taste rounder and less obviously roasted.
• Sun-drying (shai qing, 晒青). Rare as a finished green; mostly used for Yunnan material that goes on to become raw pu-erh.

The firing step matters more than any later decision. A tea fired too lightly keeps a raw, grassy edge and goes stale quickly. Fired too hard, it picks up a baked or even scorched note that no brewing temperature will remove.

The Four Firing Styles Compared

Style	Typical parameters	Where you meet it	Effect on the cup
Pan-fired	180 to 220 °C, 5 to 15 min	Longjing, most Zhejiang and Anhui greens	Toasty, chestnut, fuller body
Steamed	100 °C steam, 20 to 45 s (fukamushi 60 to 120 s)	Japanese sencha, Enshi Yulu	Bright green, grassy, marine, more umami
Baked	100 to 130 °C hot air	Taiping Houkui, many Anhui greens	Softer, rounder, less roast character
Sun-dried	Ambient sun, intermittent	Yunnan material for raw pu-erh	Light, sweet, built to age

A Working Map of Chinese Green Teas

There are hundreds of named greens. These are the ones you will actually meet, and each one is worth knowing because it shows a different corner of what the category can do.

Tea	Origin	Leaf form	One detail worth knowing
Longjing (Dragon Well)	Xihu district, Hangzhou, Zhejiang	Flat, smooth, spear-shaped	Hand-firing uses around ten named hand movements. Longjing 43 (龙井43) is the planted clone, Qunti (群体种) the older seedling stock, and Wuniuzao (乌牛早) buds a week or two earlier and is widely sold as Longjing from outside the region.
Biluochun	Dongting Mountain, Suzhou, Jiangsu	Tight spiral, heavy silver down	Traditionally grown among peach and plum trees. Its old local name is often rendered as "scary fragrant" (吓煞人香).
Huangshan Maofeng	Huangshan, Anhui	Loose, slightly curled, downy buds	Picked at roughly 700 to 1200 m, where cooler nights slow growth and build amino acids.
Anji Baicha	Anji, Zhejiang	Needle-like, pale	Despite the name it is a green tea. It comes from a temperature-sensitive albino cultivar (Baiye No.1) whose young leaves go pale in cool spring weather and carry noticeably more free amino acids than a normal green.
Taiping Houkui	Taiping, Anhui	Very large flat leaves, 5 to 7 cm	Pressed flat between mesh during firing. One of the few greens where a big leaf is the point rather than a defect.
Xinyang Maojian	Xinyang, Henan	Thin, tight needles	A northern growing area, so the first flush comes later than in Zhejiang, often into April.
Enshi Yulu	Enshi, Hubei	Straight, dark green, pine-needle	One of the few surviving Chinese steamed greens, and closer in character to Japanese sencha than to anything else made in China.

Japanese Greens Work on a Different Axis

Chinese green tea is sorted mostly by shape, region and picking date. Japanese green tea is sorted mostly by how the leaf was grown and how it was finished, and the two systems do not map onto each other cleanly.

The big extra variable in Japan is shading. Covering the plants for roughly three weeks before picking cuts photosynthesis, which forces the plant to hold onto nitrogen compounds. Catechins fall, theanine and chlorophyll rise, and the resulting tea tastes thick and savoury rather than bright and grassy. Gyokuro and matcha are both shaded; sencha is not, or only briefly.

• Sencha is the everyday tea: unshaded leaf, steamed for 20 to 45 seconds, rolled into needles. It is the reference point for Japanese green tea flavour.
• Fukamushi sencha is steamed two to three times longer. The leaf breaks up, the liquor goes cloudy, and the cup is rounder and less sharp.
• Gyokuro is shaded leaf, brewed cool at 50 to 60 °C with a high leaf ratio. It is closer to a broth than a tea, and it is why people describe some Japanese greens as savoury.
• Matcha is shaded leaf that has been steamed, dried, de-stemmed and stone-ground into powder. Because you drink the whole leaf rather than an infusion of it, a 2 g serving carries considerably more caffeine than a cup of steeped sencha, often 60 to 70 mg. Usucha (thin) is around 2 g whisked in 60 to 70 ml; koicha (thick) is closer to 4 g in 40 ml and is not whisked to a froth.
• Hojicha is roasted leaf or stem, usually at 160 to 200 °C. Roasting drives off much of the caffeine and replaces the grassy notes with toasted, caramel ones, which is why it is the Japanese green people give to children and drink in the evening.
• Bancha and kukicha are made from later, coarser leaf and from stems respectively. Both are lower in caffeine and more forgiving of boiling water.

One practical consequence: Japanese greens are usually brewed cooler and with more leaf than Chinese ones, and they rarely survive a second or third infusion as well as a good Chinese green does.

Grades Track the Calendar, Not Just Skill

Chinese green tea is graded heavily by picking date. Mingqian (明前), picked before the Qingming festival around 5 April, sits at the top of the price ladder. Yuqian (雨前), picked before Grain Rain around 20 April, comes next. After that, prices fall quickly.

Earlier is not automatically better for the person drinking it. Bud-heavy early pickings are aromatic and sweet but often thin in body, and they punish hot water. Later pickings have more substance and more pleasant bitterness, and they usually tolerate higher temperatures. For a tea you drink every day, a well-made Yuqian lot is frequently better value than an expensive Mingqian one. The exception is if you specifically want that delicate, sweet, almost watery first-flush character, in which case nothing else will do.

What Is Actually in the Cup

A 240 ml cup of green tea typically carries something in the range of 20 to 45 mg of caffeine. That is a wide band for a reason: cultivar, leaf grade, water temperature, leaf-to-water ratio and steeping time all move it, and a strong gongfu brew can sit well above a western-style one. For comparison, the same volume of black tea usually lands near 40 to 70 mg, and drip coffee near 95 mg.

Green tea also contains L-theanine, an amino acid that appears in very few plants outside tea and one particular mushroom, and a set of catechins, of which EGCG is usually the largest single fraction. Theanine is a large part of why shaded greens like gyokuro taste savoury and why green tea feels different from coffee at similar caffeine levels. Catechins are what turn astringent and bitter when the water is too hot or the steep too long.

Brewing Numbers That Hold Up

There is no single correct recipe, but there are ranges that rarely disappoint.

Tea	Water	Leaf per 150 ml	First infusion	Notes
Delicate bud greens (Biluochun, top Maojian)	75 to 80 °C	3 g	45 to 60 s	Hotter than this and the sweetness goes
Longjing and other flat pan-fired	80 to 85 °C	3 g	60 to 90 s	Glass or porcelain, not a thick clay pot
Japanese sencha	70 to 80 °C	3 to 4 g	60 to 90 s	Cooler for first flush, warmer for later
Fukamushi (deep-steamed) sencha	80 °C	3 g	45 to 60 s	Broken leaf, extracts fast, cloudy liquor is normal
Gyokuro	50 to 60 °C	5 g	120 s	Shaded for roughly three weeks before picking; thick and savoury
Baked greens (Taiping Houkui)	85 to 90 °C	3 g	60 to 90 s	Large leaves need room; use a tall glass

Two ratios cover most situations. Western style is about 3 g per 150 ml with two or three infusions. Gongfu style is closer to 5 g per 100 ml with short 20 to 30 second infusions, which will give you five or six before the leaf gives out. Neither is more authentic; they produce genuinely different drinks.

Water matters more than most people expect. Something in the region of 50 to 150 mg/L total dissolved solids tends to extract well. Very hard water mutes aroma and leaves a dull film on the surface, and heavily filtered or distilled water can produce a thin, hollow cup. If your tap water leaves scale, filter it, but do not strip it to zero.

Storage: Where Most Green Tea Dies

Finished green tea leaves the factory at roughly 5 to 7% moisture. Above that, quality falls away quickly. The enemies, in rough order of how fast they do damage, are heat, oxygen, light, moisture and whatever is sitting next to the tin.

• A sealed, opaque tin in a cupboard is fine for a few weeks.
• Refrigerate at 0 to 5 °C, sealed and genuinely dry, for a few months.
• Freeze at -18 °C or below for anything you plan to keep past a season, in an airtight bag with the air pushed out.
• Let a cold package come back to room temperature before you open it. Condensation landing on cold leaf will do more damage in one minute than a week in the cupboard.

Most delicate greens are at their best within 6 to 12 months of harvest. Pan-fired greens with more roast tend to hold up a little longer. Anything sold to you as "aged green tea" deserves scepticism; unlike white or dark tea, green tea does not improve with years. See the practical home storage methods and the storage environment reference values for more detail.

What the Health Research Does and Does Not Show

Green tea is studied more than any other tea, which is not the same as being proven to do anything dramatic. The honest summary is that most of the evidence is observational: populations that drink a lot of green tea tend to show somewhat lower rates of certain conditions, but people who drink a lot of green tea also differ in many other ways, and controlled trials have produced mixed results with modest effect sizes.

Two things are more solidly established and more immediately useful. Tea polyphenols can reduce absorption of non-heme iron when drunk with a meal, which matters if you are iron deficient or vegetarian and relying on plant sources. And green tea contains vitamin K, so drinking large quantities can interfere with warfarin and similar anticoagulants. If you are pregnant, on blood thinners, or managing a condition, ask a clinician rather than a tea seller. Details in benefits supported by modern research and contraindications and precautions.

Buying Without Wasting Money

• Ask for the harvest date. A seller who cannot tell you when the tea was picked probably does not know much about it. For a delicate green, anything past 12 months is a compromise.
• Insist on a specific origin. "Chinese green tea" tells you nothing. "Xihu Longjing" or "Dongting Biluochun" tells you a great deal, and a seller using the specific name honestly has more to lose.
• Smell it before you commit. Fresh green tea smells clean, sweet and slightly grassy or nutty depending on firing. Stale tea smells like hay, cardboard, or nothing much at all.
• Buy smaller amounts more often. Two 50 g purchases across a year beat one 100 g purchase that goes flat after four months.
• Treat very cheap Mingqian Longjing with suspicion. Labour, not leaf, is most of the cost of a top-grade early picking. The arithmetic rarely works.

More on this in common buying traps and the practical buying process.

Where to Go Next

If you want to understand why the same plant produces six different categories, read about green tea processing and craft. If region matters more to you, start with origin and growing regions. For identifying what you already have, named varieties and grades and quality and identification are the practical references. And if you only drink one Chinese green tea, make it West Lake Longjing, because almost every idea in this article shows up in it somewhere.

Green tea is the category where the maker stops everything. The other five are what happens when different things are allowed to run: black tea oxidises the leaf fully, oolong stops partway and then roasts, white tea never kills the enzymes at all and simply dries, yellow tea lets the leaf sweat under a damp cloth first, and pu-erh hands the whole job to microbes.

Practical Takeaway

Green tea is a fresh product with a short window. Buy a specific tea from a specific place, check the harvest date, keep it cold and sealed, and brew it cooler than you think you should. Do those four things and the category stops being a lottery. Skip any one of them and no brewing skill will save the cup.