Storing Matcha Through Humid Weather

Rising humidity and temperature together create the worst conditions for powder.

What happens

Caking Moisture on particle surfaces forms bridges that harden into clumps.

Accelerated change Higher temperature speeds oxidation and aroma loss. Matcha's green comes from chlorophyll, which is heat-sensitive.

A spot that worked in winter may not in summer.

Avoid sunny windows, the area near a stove or toaster, under the sink, and near a rice cooker. Each fails on either temperature or humidity.

The back of a cupboard or a dry drawer is better.

In hot weather it starts to make sense, with one condition.

Opening a cold container causes room moisture to condense inside. Water on the powder accelerates deterioration sharply.

Let the sealed container reach room temperature before opening — several hours. That makes it impractical for something you use daily.

Keeping a small portion at room temperature and refrigerating the rest is the workable version.

A dehumidified room is fine for storage.

The issue is when the air conditioning goes off. A closed room heats up and humidity climbs, which matters in households empty during the day.

On humid days, keep the package open as briefly as possible. Take what you need and close it.

Use a dry measuring spoon and do not leave it inside the bag.

Reducing purchase size for the season is a legitimate strategy.

At 20 g per serving, 300 g is 15 cups. Switching to smaller packages through the humid months removes most of the problem.

Light clumps break up with a dry spoon and pass through a strainer. Moisture is present though, so use it promptly.

Stop if the smell has changed or spots have appeared.