Catechins at a Glance
- Definition: Catechins are a subgroup of flavonoids (polyphenols) and the dominant compound class in unoxidized tea.
- Name origin: The term comes from "catechu," the extract of the catechu acacia (Acacia catechu) – not from tea, even though tea is catechins' best-known source.
- Main types: The four key catechins in tea are EC, ECG, EGC, and EGCG – the latter often makes up 50 to 80% of total catechin content.
- Where to find them: Green and white tea contain the most catechins, since they stay unoxidized – especially fine varieties like sencha, gyokuro, or matcha.
- Taste: Catechins are behind tea's bitterness and astringency – that slightly puckering mouthfeel typical of green tea.
- Effects: Catechins are among the most extensively researched antioxidant compound groups – their concrete effects are still being studied.
Definition
What are catechins? Catechins are natural plant compounds from the flavonoid group, a subgroup of polyphenols. They occur mainly in the tea plant, plus smaller amounts in cocoa, apples, grapes, and berries. In tea, they form by far the largest group of polyphenols and shape both the flavor and color of the brew.
Description
The umbrella term "catechins" actually covers several compounds. Four matter for tea: Epicatechin (EC), Epicatechin gallate (ECG), Epigallocatechin (EGC) and Epigallocatechin gallate (EGCG). The latter is by far the most researched and often makes up 50 to 80% of total catechin content in good green tea. Catechins are the dominant subgroup of flavonoids in tea.
How many catechins end up in your cup depends heavily on processing. Green tea is heated right after harvest – steaming or pan-firing stops oxidation before it can convert the catechins on a large scale. That's why green tea often contains over 10% catechins by dry weight. Black tea usually sits at just 1 to 12%, because most of its catechins get converted into theaflavins and thearubigins during full oxidation – new polyphenols responsible for black tea's dark color and bolder flavor.
Brewing matters too: catechins are water-soluble and dissolve straight into the water. Softer water under 80°C (176°F) extracts more of them than hard, boiling water, which breaks down some of the delicate molecules. The longer a tea steeps, the more catechins end up in your cup – but so does the bitterness.
Catechins in Tea
Not every tea contains the same amount of catechins. Green and white tea stay unoxidized and retain most of their original catechins – they're considered especially catechin-rich, particularly fine varieties like sencha, gyokuro, or long jing. Matcha stands out even further: since you drink the whole, finely ground leaf instead of just an infusion, you take in significantly more catechins than with classic brewed tea.
Oolong sits in the middle, both in taste and composition: only part of the catechins oxidize, part remain intact. Black tea goes through full oxidation, and pu-erh undergoes an additional microbial fermentation – both end up with far fewer original catechins, but other polyphenols newly formed during processing.
Catechins: Effects
Catechins are among the most thoroughly researched plant compounds out there – mainly for their antioxidant properties. Studies are looking into their role in protecting cells from oxidative stress, in metabolic processes, and in normal cardiovascular function – but the research is still ongoing, and no confirmed results exist yet for humans. Many of these studies use isolated, high-dose extracts in lab settings – so the findings don't translate one-to-one to a cup of tea in everyday life. What we can say: if you drink green tea or matcha regularly, you're naturally taking in one of the most catechin-rich ingredients out there.
Historical Background
The name "catechin" originally has nothing to do with tea. It comes from "catechu," the tannin-rich extract of the catechu acacia (Acacia catechu), used for centuries across South and Southeast Asia for tanning leather and dyeing textiles. When 19th-century chemists took a closer look at this extract's components, they isolated a previously unknown compound – and named it after its source: catechin.
Only later did it turn out that structurally related compounds also occur in the tea plant – where they actually form the dominant polyphenol group. In East Asia, people had long known about tea's special qualities without understanding the chemistry behind it: green tea was linked to vitality and wellbeing in China and Japan centuries ago. It wasn't until modern analytics emerged in the mid-20th century that catechins in tea could be precisely detected and distinguished. From the 1990s onward, EGCG in particular moved into the spotlight of international research – becoming one of the most studied plant compounds worldwide.
Fun Facts
- Not named after tea: The name "catechin" comes from the catechu acacia, not the tea plant – a mix-up that persists to this day.
- EGCG dominates: In high-quality green tea, EGCG alone often accounts for 50 to 80% of total catechin content.
- Matcha brings the most: Because you consume the whole leaf, matcha delivers significantly more catechins than brewed tea made from the same amount of leaf material.
- Younger leaves, more catechins: Delicately picked first-flush harvests usually contain the season's highest catechin concentration.
- Oxidation transforms, doesn't destroy: Even heavily oxidized teas like black tea still contain catechins – just in a converted form, as theaflavins and thearubigins.
- Catechins are heat-sensitive: Boiling water can break down some catechins – one reason lower temperatures are recommended for high-quality green tea.
