Nitrogen Flushing

Nitrogen flushing is a packaging method that replaces oxygen inside a package with nitrogen to help slow changes in the color, aroma, and flavor of matcha while it remains unopened. Oxygen can contribute to oxidation, so reducing oxygen in the package is one way to support quality during storage.

How it differs from oxygen absorbers

A related term is “oxygen absorber.” An oxygen absorber is usually a small packet placed inside a container to absorb remaining oxygen. Nitrogen flushing works differently: air is displaced with nitrogen at the time of packing. Both approaches aim to reduce oxygen, but the mechanism and the way they appear on packaging are different.

Nitrogen flushing is not a cultivation technique. It belongs to the packaging stage, after tea leaves have been processed into tencha and milled into powder. Matcha has a large surface area because it is a fine powder, so oxygen control at packing can be part of overall quality management. ICHIZEN’s Kyoto Uji matcha is selected and refined by Wakimoto Jokoen and machine-milled into an ultra-fine, uniform powder.

After opening

The benefit of nitrogen flushing mainly applies before the package is opened. Once opened, outside air enters, and the powder is exposed to oxygen and moisture whenever it is measured, whisked, or used in cooking.

For everyday use, take out only what you need, close the package promptly, and keep scoops and whisks dry. Store matcha away from heat, light, moisture, and strong odors; refrigeration may be useful depending on your storage conditions. For more detail, see our guide to how to store matcha.

“Nitrogen flushed” is a packaging term, not a grade name and not a guarantee of a specific taste. It is best understood as a practical measure to help preserve the character of matcha before opening.