Reference
Myths, checked
A fair amount of what gets repeated about tea is plausible rather than verified. These are the claims that can be settled with numbers. Where the evidence does not settle it, the verdict says so.
“Gyokuro tastes gentle, so it must be low in caffeine”
Not true- What's actually true
- The opposite: it sits at the high end for Japanese tea. The Standard Tables of Food Composition in Japan give 3.5 g of caffeine per 100 g of gyokuro leaf against 2.3 g for sencha, and 0.16 g per 100 mL of gyokuro liquor against 0.02 g for sencha.
- Why it gets said
- Brewed cool, it feels round and unaggressive in the mouth. But the eight-fold gap in the liquor is not all content. The composition tables brew gyokuro as 10 g of leaf in 60 mL of 60°C (140°F) water for 2.5 minutes, and sencha as 10 g in 430 mL at 90°C (194°F) for one minute — gyokuro is simply made about seven times more concentrated. If you are watching caffeine, how strong you brew matters more than which tea you choose.
“The more expensive the tea, the more catechins”
Not true- What's actually true
- Gyokuro carries 10.0 g of tannins (catechins) per 100 g of leaf against sencha's 13.0 g. Price and grade do not track catechin content.
- Why it gets said
- Shading suppresses catechin formation and leaves more of the savory amino acids like theanine in the leaf — which is exactly why gyokuro tastes sweet. Gyokuro is a tea deliberately made to have fewer catechins. If catechins are what you want, sun-grown sencha or bancha is the better choice.
“There is nothing left in the second infusion”
Not true- What's actually true
- There is. Most of it comes out first, but the second infusion still extracts — and faster, because the leaf is already open.
- Why it gets said
- The first cup is strong enough that it feels like everything came out at once. In practice, steeping the second as long as the first usually turns it astringent. Use hotter water and cut the time hard.
“Cold brewing means no caffeine”
Not true- What's actually true
- It lowers it; it does not remove it. Caffeine simply dissolves slowly at low temperature — given hours, it still comes out.
- Why it gets said
- Cold brew tastes smooth and unaggressive, which reads as 'nothing stimulating in here'. If you genuinely want less caffeine, choose a tea that starts with less — kukicha, or a roasted bancha — rather than relying on the water temperature.
“Want it stronger? Just leave it longer”
Not true- What's actually true
- Longer steeping adds astringency faster than it adds strength. To change strength, change the amount of leaf.
- Why it gets said
- Savory compounds dissolve early; astringency builds late. The advice conflates 'strong' with 'harsh'. Keep the time where the tea wants it and let the leaf weight set the strength.
“Matcha is just green tea ground into powder”
Not true- What's actually true
- Matcha is ground tencha — shade-grown leaf dried without rolling. Ground sencha is powdered green tea, which is a different product from a different field.
- Why it gets said
- Both are green powder, so they look interchangeable. The ingredients line separates them. Plenty of 'matcha-flavored' sweets and drinks use powdered green tea.
“Japanese tea is all green tea”
Half true- What's actually true
- Most of it, but not all. Kamairicha from Miyazaki and Kumamoto is pan-fired rather than steamed; wakōcha is fully oxidized black tea; Kochi's goishicha and Tokushima's awa bancha are post-fermented by microbes.
- Why it gets said
- Steamed green tea so dominates the market that the rest is easy to miss. The same plant becomes a different tea depending on how oxidation is stopped — or encouraged.
“Never use boiling water for Japanese tea”
It depends- What's actually true
- It depends on the tea. Gyokuro, kabusecha and high-grade sencha turn astringent above their range, but hojicha, genmaicha and bancha want water straight off the boil — the toasty aromatics need the heat.
- Why it gets said
- 'Japanese tea is delicate, so keep it cool' spread as a single rule. Temperature is per tea type; the seven on the front page each carry their own range. And even when you want cool water, boil it first and let it fall.
“A floating tea stem is a sign of good luck”
It depends- What's actually true
- Folklore, unrelated to flavor. A stem has to be in the packet for it to happen at all, and modern sorting takes most of them out. Kukicha, which is all stem, does it readily.
- Why it gets said
- The usual explanation is that stems meant coarser sorting, so it was rare enough to read as a good omen. The origin story cannot be verified; the part that can is that today's finished tea rarely does it.
“Shincha is the best tea of the year”
It depends- What's actually true
- A matter of taste. New tea is bright and green in aroma, but its astringency and savoriness have not settled. Kuradashi tea — held cool until autumn — is prized precisely because it rounds out.
- Why it gets said
- Shincha arrives once a year and costs more, which reads as 'best'. Being first flush (a fact about the leaf) and being sold early in the season (a fact about the calendar) are two different claims.
Composition figures come from Japan's Standard Tables of Food Composition. Liquor values only mean anything alongside the brewing conditions the tables specify — gyokuro as 10 g of leaf in 60 mL at 60°C (140°F) for 2.5 minutes, sencha as 10 g in 430 mL at 90°C (194°F) for one minute. Brew a tea to a different strength and the numbers move with it.
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