Can you use metal with matcha? The myth, and what to avoid

Yes, you can use metal with matcha. A stainless steel spoon, a metal strainer or a metal jar will not spoil the tea in the seconds or minutes it touches them. The idea that metal ruins matcha is one of the most repeated tips online, and it does not survive a look at the tea room itself, which is full of metal.

The short answer: metal does not harm matcha. Bamboo is traditional for other reasons: a bamboo scoop will not scratch a lacquered caddy, and a bamboo whisk makes a fine foam that a metal whisk cannot. The one thing to avoid is leaving wet tea on bare, rusting iron, because tea and iron react and turn dark.

I study tea in Tokyo, in the Urasenke school, and I choose the tools in this shop. Here is where the metal is in a traditional tea setting, and why bamboo still wins in two places.

The tea room is full of metal

If metal spoiled matcha, the tea ceremony would have a problem. The kettle, the kama, is cast iron, and the water for every bowl is boiled in it in front of the guests. The tea you buy from the old tea houses in Kyoto comes in a metal tin, and it sits in that tin for weeks. Most sifters, in Japan and elsewhere, press the powder through a fine wire mesh.

None of this is treated as a compromise. The iron kettle is one of the most admired objects in the room, and the tin is simply the best way to keep light and air away from the powder.

Where the myth comes from

There are two real things behind it, and both are about particular tools, not about metal touching tea.

The first is the whisk. A coiled metal whisk is too stiff and too widely spaced to build the fine foam that makes thin tea smooth. People who tried it saw a flat, lumpy bowl and blamed the metal. The problem was the shape, not the material. I go through the difference in why matcha will not froth, and the whisk against the electric frother as well.

The second is the caddy. Matcha for the tea room is kept in a lacquered caddy, a natsume. Lacquer is hard but it scratches, and a metal spoon dragged along the inside leaves marks. A bamboo scoop does not. That is a reason to protect the caddy, and it got passed on as a reason to protect the tea.

What to actually avoid

The one real reaction is between tea and iron. Tea contains tannins, and tannins combine with iron to make a dark compound. It is the same chemistry that made iron gall ink, the ink of old manuscripts. An iron kettle that only ever boils water is fine, and cast iron teapots made for brewing are enameled inside for this reason. The trouble comes when wet tea sits on bare iron that has started to rust: the tea darkens and picks up a metallic taste.

So the practical rules are short:

• Stainless steel is fine for spoons, strainers, jars and shakers.
• Keep matcha tins dry and closed. Moisture spoils matcha long before any metal would.
• Do not leave wet tea on rusty iron. Rinse and dry iron things.
• Do not use a metal spoon inside a lacquered caddy. Use the bamboo scoop, or tip the powder out.

Why bamboo is still worth having

I use bamboo for scooping and whisking, and not out of superstition. The scoop, the chashaku, is light and shaped so that one heaped scoop holds about a gram, which makes it easy to measure a bowl by eye. How much it holds, heaped and level, is in how many grams is a chashaku scoop.

The whisk matters more. A bamboo chasen has around a hundred fine tines that are flexible at the tips, which is what breaks up the powder and lifts a smooth foam. No metal tool does that job as well. If you only change one thing, change the whisk, not the spoon.

Questions I get asked

Can you use a metal spoon for matcha?

Yes. A metal spoon will not change the taste. Avoid it only inside a lacquered caddy, where it can scratch the lacquer.

Why do people say not to use metal with matcha?

Mostly because of two real issues with particular tools: metal whisks make poor foam, and metal spoons scratch lacquered caddies. Neither is about metal damaging the tea.

Can I use a metal whisk for matcha?

You can, but the result is flat and often lumpy. A bamboo whisk makes a much finer foam. The reason is the shape of the tool, not the metal.

Can I use a metal strainer to sift matcha?

Yes. A fine mesh strainer works well, and many sifters made for matcha use a metal mesh. Make sure it is completely dry. A damp sifter clogs, as I explain in sifting matcha.

Can matcha be stored in a metal tin?

Yes. Tea houses in Japan sell matcha in metal tins because they keep out light and air. Keep the tin closed and dry, and see how to store matcha for the rest.

Where this fits

The two bamboo tools worth having are a white-bamboo scoop and a 100-prong Takayama chasen. For lumps, a fine sifter does more than any change of spoon. The whole method is in how to make matcha.

Written by Mio.K, who chooses everything in this shop by hand in Japan.