How Green Tea Is Faked, and How to Spot It

Green tea fraud takes four forms: origin substitution, grade inflation, colouring and the sale of old tea as new. All four are labelling and presentation problems rather than adulteration, and all four are cheap to commit. Colouring is the only one that involves adding something to the leaf, and it is rare but real.

The reason the fraud is common is that the price differences between claims are large and the claims are hard to check. A Mingqian Longjing and a post-Mingqian Sichuan leaf can differ tenfold in price and be difficult to separate in a photograph.

The four methods

Origin substitution is by far the most common and the least harmful. The leaf is real tea, it is simply from a different place, and a well-made substitute can be a good drink.

Grade inflation is the second. A tea picked in late April is sold as a Mingqian tea, and the difference is in the leaf size and the tenderness rather than in the appearance of the tin.

Colouring is the third and the only one that adds a substance. Green tea has been coloured with copper chlorophyllin, tartrazine and indigo to make a dull leaf look fresh, and the practice is illegal in most markets and prosecuted occasionally.

Selling old tea as new is the fourth. A previous season’s tea is re-fired to restore crispness and sold as the current crop, and the aroma is the tell because a re-fired tea smells flat and slightly cooked.

How to catch each one

Origin substitution is caught by comparison. A drinker with a reference sample of a known tea can taste a substitute immediately, and without one the task is much harder.

Grade inflation is caught by the wet leaf. A Mingqian tea shows small, tender, even leaves after brewing; a later pick shows larger and coarser ones, and the difference survives any packaging.

Colouring is caught by a simple test. Rub the dry leaf on a damp white paper or cloth: a coloured tea leaves a green or blue stain, and a natural tea leaves almost nothing. The liquor of a coloured tea is also unnaturally bright and can leave a ring on the cup.

Old tea sold as new is caught by the smell and the colour. A fresh green tea smells of chestnut or the sea; a re-fired one smells flat and slightly toasted, and the leaf is yellowed rather than green.

• Origin substitution is the commonest and the least harmful.
• Grade inflation shows in the wet leaf.
• Rub the dry leaf on damp white paper to test for dye.
• A coloured tea leaves a green or blue stain.
• Old tea re-fired smells flat and slightly cooked.
• Comparison with a reference sample catches the first and the largest.

Why the fraud persists

The claims that carry the largest premium are the ones hardest to check. Mingqian, core area and hand-picked are all claims about when and where, and neither is visible in the finished product.

Enforcement is local and the market is enormous. A provincial authority can inspect producers within its jurisdiction and cannot inspect a shop on another continent.

And the buyer often cannot taste before purchase. A sealed tin or an online order offers no opportunity to check, and the label is the only information.

That combination, high premiums on unverifiable claims and a market that spans jurisdictions, is what makes the fraud profitable and persistent.

A buyer’s defence is the same in every case: buy small, compare against a reference, and prefer a producer who can be questioned.

The colouring problem in detail

Colouring has a long history in the tea trade and it was more common in the nineteenth century than now. The motive is to make a dull or yellowed leaf look fresh, and the substances used include copper chlorophyllin, tartrazine and indigo.

The practice is illegal in China and in most importing markets, and it is prosecuted when it is found. It persists because detection requires a test that a consumer cannot easily run and an inspector rarely does.

The paper test is the consumer’s version. Rub a few leaves on damp white paper: a natural tea leaves a faint brown-green mark at most, and a coloured one leaves a clear green or blue stain.

The liquor is the second check. A coloured tea brews an unnaturally vivid green and can leave a ring of colour on the inside of the cup, which a natural tea does not.

• Colouring makes a dull leaf look fresh.
• Copper chlorophyllin, tartrazine and indigo are the usual agents.
• It is illegal and prosecuted, and it persists.
• The paper test is the consumer’s check.
• A natural tea leaves at most a faint mark.
• A coloured tea brews unnaturally bright and can ring the cup.

Why old tea sold as new is the mildest case

A previous season’s tea is real tea from the right place and it is simply older than claimed. It is flat and it should be cheaper, and the dishonesty is about the price rather than the safety.

That makes it the easiest fraud to forgive and the hardest to detect, because a well-stored green tea at twelve months is not obviously wrong. The aroma is the only reliable tell.

A drinker should treat a green tea bought out of season with suspicion and ask for the harvest date. A producer who cannot give one is selling an unknown age.

The same advice applies to every form of fraud on this page: the date and the garden are the two facts that make a claim checkable, and a tea without them is a tea without evidence.

The grade claim and the wet leaf

Grade inflation is caught by the wet leaf and by nothing else. A Mingqian tea shows small, tender, even leaves that are still whole after brewing; a later pick shows larger, coarser leaves and more stem.

The difference survives every packaging trick because it is in the leaf rather than on it. A buyer who brews a tea once and looks at what is left has the evidence.

That check also catches leaf substitution, where a coarse leaf is sold as a fine one under a name that implies a high grade.

It is the most reliable test on this page and it costs a single infusion.

• Grade inflation is caught by the wet leaf.
• Mingqian leaf is small, tender and whole after brewing.
• A later pick shows larger leaves and more stem.
• The evidence survives every packaging trick.
• The same check catches leaf substitution.
• It costs one infusion and settles the claim.

A buyer who runs the paper test and looks at the wet leaf has caught the two frauds that involve a physical difference, and the other two are caught by asking for the date and the garden.

That is the whole defensive toolkit, and none of it requires equipment beyond a piece of white paper.

What the market does about it

Producer associations in the famous regions run inspection schemes and issue marks, and the schemes work within their own area and cannot follow a tin abroad.

Some large buyers run their own testing, particularly for colouring, because a scandal would damage them more than the testing costs.

Neither approach solves the problem for a small purchase. The consumer is left with the paper test, the wet leaf and the questions about date and garden.

That is a modest toolkit and it catches the physical frauds and the obvious age claims, which is most of what a buyer will meet.

The rest is a matter of buying from a source that has something to lose, which is the same advice as for every other tea on this site.

That is the whole of the fraud question, and every item on the list costs less than a tin of the tea it protects.

A buyer who uses it will still occasionally be sold a substitute, and will at least know what he has bought rather than being told a name and believing it.

Frequently asked questions