Storage affects catechin content of loose leaf green tea

Loose leaf green tea is the freshest green tea available with the least amount of processing. Other types of green tea such as blended teas, instant teas, bottled teas, tea bags, and decaffeinated teas go through more processing.

The best whole leaves are packaged and sold as loose green tea. The broken leaf pieces, stems, and leftovers are used to process instant teas, bottled teas, and tea bags.

Catechins of loose leaf green tea

The catechin content depends on several factors. The catechin content can change according to how the leaves are manufactured. Fresh tea has the least amount of manufacturing, so it has the highest catechin content.

Bottled teas, tea bags, and decaffeinated teas go through more processing, which results in a lower amount of catechins (about half the amount as whole tea leaves).

Catechins and storage

Storage can also affect the catechin content. The catechins can degrade over time if the tea is not stored in proper packaging. Many bagged teas are not packaged properly and lose their potency and flavor over time.

The average shelf life of loose leaf green tea is approximately two years. There is minimal change if the tea is stored properly and used within two years.

The best packaging is metalized multilayer polyethylene film, similar to the packaging used for some brands of potato chips or candy bars. At room temperature, tea in this packaging can remain completely unchanged for six months.

From six to twelve months, there is very little change. However, after a year, the tea starts to slightly change, and the flavor becomes a bit mustier. Then, after two years, the tea begins to lose its beneficial properties, potency of catechins, and flavor.

It’s difficult to know how long a box of tea has been sitting on the shelf at a store. If you’re looking at teas at the store, I recommend choosing one that has the furthest expiration date (at least a year to be safe).

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