How Long Does Green Tea Last?

The green tea you discovered at the back of your cupboard is well past its “best by” date? Now you’re wondering “Can I still use this tea, how long does green tea last?”

The good news is that, as long as it was stored correctly, you’ll probably not have to waste the tea. You should still be able to use the leaves or tea bags, although the tea won’t taste quite as fresh and might have lost some of its health benefits.

Here we explain why dry green tea leaves don’t expire and what happens as the tea gets older. You can also learn about the best way to store tea and how to tell if your tea is no longer safe to drink.

How Long Do Green Tea Leaves Last?

Tea packaging usually specifies a “best by” date, rather than an expiry date. This is because you can still use the tea for months after the given date. Dry tea leaves don’t go bad in the sense that it’s unsafe to drink.

However, for the best aroma, flavor and nutrient value, you should try to use your tea as soon as possible after you buy it. The “best by” date for green tea is usually between 12 and 36 months after manufacture, which is shorter than for black tea.

Green tea and black teas are both manufactured from the leaves of the Camellia sinensis plant. Green tea is made from the leaves and buds of the plant and is not subjected to the same oxidation and fermentation processes as black and oolong tea.

This is what gives green tea its lighter color and fresh and grassy flavor. But this also means that it has a shorter shelf life than black tea if the unique aroma and health properties are what you are after.

Furthermore, loose tea leaves last longer than tea bags. This is because the smaller fannings and dust used in tea bags have a greater surface area interacting with the air than larger tea leaves.

What Happens When Green Tea Ages?

Air, light, heat and moisture all affect the chemical composition of tea.

When exposed to moisture, including the normal moisture in the air, green tea leaves will start oxidizing. As a result, they might lose their light green color and turn brownish.

Bacteria, mold and insects usually stay away from dry tea leaves. However, with excessive moisture, tea leaves can start to rot and grow moldy.

Exposure to direct sunlight can cause green tea to lose most of its scent after only 30 minutes. This is something to keep in mind when you are transporting your tea from the shop to your home on a very hot day.

An in-depth study showed that extended storage affected the appearance, aroma and taste of green tea leaves. After 150 days of storage at 39˚F (4˚C), expert tasters rated both the aroma and taste of the tea at -1.0 compared to 4.0 at the beginning of the experiment. (1)

The health benefits of green tea are derived from the antioxidant properties of the polyphenols, which also contribute to its aroma and taste. A study that measured the effect of storage on these health-related compounds found that the tea lost 58.62% of its antioxidant capacity after being stored for only nine days in normal commercial conditions. (2)

From the above, it is clear that you should try and use your green tea as soon as possible and also pay attention to how you store it.

How Do I Make Green Tea Last Longer?

• Store tea in an airtight container, avoid opening it frequently and seal the pouch well after use.
• Store tea in a cool, dark place to protect it from light and heat. This is why a tea tin is ideal. Obviously you should avoid keeping tea in a clear glass container.
• Make sure your teaspoon is dry when you scoop out tea leaves.
• Tea bags that are sealed in individual pouches are a bit more expensive, but will last longer.
• If you’ve bought more tea than you could consume within a reasonable time it will last longer in the fridge. But the container must be very well sealed to keep out any moisture.
• Protect tea from contamination by mold, insects and other pests which will make it unsafe to use.

How to Tell if Your Tea is Still Safe to Use?

As we have seen, you can usually still use green tea that is old, though it might be weaker and could taste stale. But your tea can go bad, even before the “best by” date on the packaging, if it is not handled and stored correctly.

To check if your tea is still safe to use:

• Have a good look at it. It isn’t usually a problem if the leaves have changed color, but discard the tea if there are any signs of contamination by mold, rot or insects.
• Smell the tea leaves. If there is no unpleasant smell the tea is probably good to brew.
• After brewing, smell the tea again and take a sip. If it smells and tastes fine, you can enjoy your cup of tea.

Takeaway

Dry green tea leaves are usually safe to use for a very long time. Unless it has become wet and spoiled by rot or been contaminated by mold or insects. Old tea will, however, have lost much of its aroma, taste and healthy properties.

Refreshing and healthy green tea is valued for its fresh grassy taste and antioxidant benefits. So, for the best tea drinking experience, we suggest that you don’t buy more green tea than you’re likely to use in a relatively short time.

References

1. Dai, Q., Liu,S., Jiang,Y., Gao, J., Jin, H., Zhang, Y., Zhang, Z. and Tao, X. 2019. Recommended storage temperature for green tea based on sensory quality. Journal of Food Science Technology. 56:9.

2. Urías-Orona, V., Niño-Medina,G. 2019. Changes in phenolics and antioxidant capacity during short storage of ready-to-drink green tea (Camellia sinensis) beverage at commercial conditions. Bragantia 78:1.