Best Water for Matcha

Taste — A basic activated-carbon jug filter removes chlorine and organic compounds, which is the majority of what makes tap water taste of tap water. In a soft-water region the result is indistinguishable from good bottled water for matcha purposes.

Performance — Carbon alone does not remove hardness. If your supply runs above about 150 ppm, you need a filter with an ion-exchange resin stage — most jug brands sell one — rather than a plain carbon cartridge.

Best for — Daily drinking anywhere with soft to moderately hard water.

Watch out — Replace cartridges on schedule. An exhausted carbon filter stops removing chlorine silently, and you will blame the matcha.

Taste — Volvic (around 130 ppm), Crystal Geyser (around 90 ppm) and Icelandic Glacial (around 60 ppm) all sit in a workable range with near-neutral pH. Matcha made with these tastes rounder and sweeter than the same powder in hard tap water.

Performance — Entirely consistent from bottle to bottle, which makes it useful for judging a new matcha.

Best for — Hard-water areas, tasting and comparing matcha, travel.

Watch out — Read the bottle. Bottled water is not automatically soft — Evian is around 300 ppm and San Pellegrino far higher. The mineral content is printed on the label.

Taste — RO strips essentially everything, then a remineralisation cartridge or a few drops of mineral concentrate adds back a controlled amount. The result is repeatable in a way no tap supply is.

Performance — Excellent, but only with the remineralisation stage. Pure RO water on its own makes hollow, lifeless matcha.

Best for — Very hard water areas, anyone already running an RO system for coffee.

Watch out — Do not skip remineralisation. Zero-TDS water is as wrong as very hard water, just in the opposite direction.

Taste — If you live somewhere with genuinely soft water, the main issue is chlorine rather than minerals. Drawing water and letting it stand uncovered for an hour lets free chlorine dissipate, though it does nothing for chloramine.

Performance — Good, with a chlorine note in the aroma that some people never notice and others find obvious.

Best for — Soft-water regions, casual daily drinking.

Watch out — Never use water from the hot tap. It sits in a tank and picks up dissolved metals and sediment.

Taste — Flat and chalky, with the sweetness and umami noticeably reduced. Calcium and magnesium ions bind to catechins and to L-theanine, the amino acid responsible for matcha's savoury depth, so the parts you paid for are the parts you lose.

Performance — Also visibly dulls the colour, shifting a vivid green toward olive. Foam is coarser and dies faster.

Best for — Nothing, if you can avoid it.

Watch out — This is worth diagnosing before you conclude your matcha is bad. Make the same bowl with bottled low-mineral water and compare — the difference is usually obvious immediately.

Taste — Hollow and thin with no body. A small amount of dissolved mineral is needed for extraction to work properly and for the tongue to register body at all. Zero-TDS water makes matcha taste like a dilute suggestion of itself.

Performance — Poor extraction across the board.

Best for — Nothing tea-related.

Watch out — Counterintuitive but consistent — purer is not better here.

Taste — At pH 9 and above, alkaline water extracts catechins far too aggressively. The result is harsh, drying and bitter, and it also darkens the colour. Whatever the health claims, this is the wrong water for matcha.

Performance — Over-extraction at any temperature.

Best for — Nothing tea-related.

Watch out — Some filter jugs sold as premium are alkalising jugs. Check what yours actually does.