Green tea (Camellia sinensis)

OriginOne plant, all types of tea

Green tea, white tea, oolong, black tea, pu-erh - these are not five plants, but five ways of handling the leaf of the same plant.

The tea plant originates from the border region of southwest China, northern Myanmar, and Assam. Two varieties are important: the small-leaved Chinese form. sinensis, which tolerates cooler altitudes and yields finer teas, and the large-leaf variety assamica, which produces stronger, tannin-rich leaves for black tea. Left unpruned, a tea bush would grow into a tree; in cultivation, it is kept at hip height so that the young shoots remain accessible.

The difference between the types of tea lies solely in the processing. After picking, enzymes in the leaf begin to oxidize the catechins – colloquially referred to as "fermenting," although no microorganisms are involved. For Green tea This process is immediately stopped: in China by roasting in a pan, in Japan by steaming. That's why Japanese green tea tastes grassy and marine, while Chinese green tea is more nutty and roasted. Black tea If the oxidation is allowed to proceed completely, for Oolong partially, for white tea Not at all - it's just withered and dried.

Culturally, tea is the second most consumed beverage in the world after water. In China, its history stretches back over two thousand years; the Japanese tea ceremony has elevated it to an art form; in Morocco, green tea with mint is the quintessential drink of hospitality. And it has become of interest to researchers because East Asian observational studies have shown that regular green tea consumption is associated with lower rates of cardiovascular disease.

To useWhat green tea does for you

There are two levels to distinguish when it comes to green tea: the beverage and the extract. When it comes to green tea, the situation is pleasantly clear. Large observational studies from Japan and China link regular green tea consumption with a slightly lower risk of cardiovascular disease and a slightly lower overall mortality rate. These are correlations, not proof—people who drink a lot of green tea differ in many ways from those who don't. But the trend is consistent across many studies, and a calorie-free beverage with a good safety profile is a sensible habit to keep.

The most famous ingredient is EGCG (Epigallocatechin gallate), a catechin with impressive antioxidant and cell-biological properties in the laboratory. However, intervention studies in humans have yielded considerably more sobering results: The effects on weight loss are so small that they are negligible in everyday life; there are small, inconsistent effects on blood lipids and blood pressure; and the numerous cancer prevention hypotheses have not yet been confirmed in controlled studies. This is a laboratory value, not a promise of a cure – and EGCG is a particularly clear example of this.

One special feature that receives too little attention is that L-Theanine. This amino acid is found almost exclusively in tea and has a relaxing effect without causing drowsiness. Combined with caffeine, this results in the characteristic "calm alertness"—tea wakes you up differently than coffee, and this is not just your imagination, but measurable. Theanine content is particularly high in shaded Japanese teas such as Gyokuro and Matcha.

And then the point that belongs on this page because it is current and serious: High-dose green tea extracts are not the same as green tea. The European Food Safety Authority (EFSA) has determined, after evaluating case reports, that preparations containing 800 milligrams of EGCG or more per day are linked to liver damage. This isn't an issue with herbal infusions, as one would have to consume unrealistic quantities. However, it is a concern with capsules and "fat burner" products containing concentrated extract. Anyone taking such preparations should check the EGCG content on the label.

IngredientsThat's what's in the leaf

The most important group of substances are the Catechins, which can make up to 30 percent of the dry mass. The best known is EGCG, Alongside these are EGC, ECG, and epicatechin. They are responsible for the tart, slightly astringent taste and for the majority of the antioxidant effect. In black tea, they are converted to theaflavins and thearubigins during oxidation – this is why black tea is dark and tastes less grassy, and why it has a different polyphenol profile.

caffeine Green tea contains a similar amount of vitamin D as coffee in terms of dry weight, but significantly less per cup because less material is used – about 20 to 45 milligrams compared to 80 to 120 in coffee. More importantly, in tea, some of the vitamin D is bound to tannins and is therefore absorbed more slowly. Along with the L-Theanine, which smooths out the stimulating effect, results in a milder, longer-lasting effect.

This leads to two clear rules for preparation. First: Do not pour boiling water over it. At 70 to 80 degrees Celsius, amino acids and milder flavor compounds dissolve well, while bitter catechins dissolve more slowly – at 100 degrees Celsius, the opposite is true, and the tea becomes bitter and astringent. Secondly: Don't let it steep for too long. Two to three minutes are enough; after that, tannins dominate. And a practical tip regarding iron: tannins bind plant-based iron significantly – those looking to build up their iron stores should drink tea between meals, not with them.

Enhanced combinationsWhat makes green tea stronger

Temperature and time determine taste and digestibility - more than any variety.

What contradicts itselfIt's best to avoid these combinations.

To which courtWhere he belongs

• SenchaJapanese everyday tea - steamed, grassy, 70 degrees, two minutes.
• GyokuroGrown in the shade, very rich in theanine, steeped at 50–60 degrees.
• MatchaGround leaf powder, whipped up - here you drink the whole leaf.
• GunpowderRolled Chinese green tea - the basis for Moroccan mint tea.
• Moroccan mint teaGunpowder, lots of fresh mint, sugar, poured in from a height.
• Cold infusionLeaves soaked overnight in cold water - sweeter, almost without bitterness and with less caffeine.
• Matcha LatteFrothy with warm milk - significantly milder than plain.
• Green tea ice creamMatcha in ice cream - the most well-known culinary use.
• OchazukeJapanese: Rice poured with green tea, with salmon or umeboshi.
• smokehouseLeaves for smoking fish and duck - a Chinese kitchen trick.

As a home remedyThe cold infusion

Ayurveda & TCMWhat the old systems say

Warning noticesWhen you should be careful

This page provides information and does not replace medical advice. If symptoms persist, please consult a doctor.

Related to the topicRead on and cook along!

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