How Long Does Green Tea Last

When we spend a lot of time, energy, and money on discovering the teas that we love the most, it is important that we get the most out of each pot. The freshest green tea leaves will almost always produce the finest tea, but after they are no longer fresh, how long does green tea last and can it be stored for?

It is a regular occurrence that tea hobbyists will buy a lot of tea throughout the year, and sometimes an extra amount when the spring harvest leaves are released. This can lead to an over-abundance of tea leaves stored in the pantry or freezer just waiting to be brewed. Some closets look like the back room of a tea shop and you think, who could possibly drink all of this?

How Long Does Green Tea Last?

Green tea lovers should know that green tea leaves (as well as white tea leaves) have the shortest shelf life out of all teas. This does not mean that they need to be brewed immediately after receiving them, but the package that your aunt brought back from China in 2002 will probably not produce a very good pot of tea. The standard shelf life of green tea is 18 months.

Tea rarely goes “bad” in the traditional food sense. The leaves are dried during processing and should not have any natural microbes or bacteria that multiply after a certain time, like meat or dairy products would. There is no sugar and very little moisture so they will not rot like fruits and vegetables. Old leaves should not make you sick unless they have become moldy.

Dates on the packaging for green tea, as with all teas, should be viewed as more of a “best by” date rather than an “expiration” date. Tea does not expire so much as it ends up “past its prime.” The end result of a tea brewed past the date on the package will probably not be as good as it would have been when first purchased.

Normally what happens with old tea leaves is that they start to lose their flavor and aroma. Green tea starts with a generally mild flavor and scent profile with many different subtle layers that will fade quickly after a certain point.

Darker versions like black tea or oolong tea, with their stronger flavors and scents, will start to break down at around the same amount of time in a pantry, but the loss of flavor will be less noticeable since they start out with so much more. 

Pu-erh tea, in fact, is purposefully aged in order to bring out different flavors through the maturing process, much like certain varieties of wine or cheese. This is possible because the leaves have gone through an additional fermentation process, activating enzymes that create a different chemical change that other forms of tea do not go through.

How Does Tea Go Stale?

If tea leaves are dried as part of their original processing, how do they end up breaking down and losing their flavor? There are a few main threats to the longevity of dried tea leaves:

• Moisture
• Heat
• Odors
• Oxygen
• Light

Moisture

When brewing a pot of tea, we see a very obvious reaction of the tea leaves immediately absorbing the hot water and expanding. The process can be exceptionally pronounced when the tea leaves are rolled into balls and they unfurl when coming in contact with water. That first contact with liquid starts the change that helps leaves express the taste and smell of tea.

Air itself can contain quite a bit of moisture. In exceptionally humid regions, the amount of water in the air can be felt on your skin, or even when you breathe. If left in the open, or in a poorly sealed container, this moisture can start the process we want to save for brewing, stealing the flavors and scents we want in our cup.

Deterioration can happen quickly in these circumstances, so keep as much humid air away from green tea leaves as possible by storing them in a properly sealed pouch or container.

Studies have shown that the increase in moisture level of stored tea will also have a detrimental effect on the amount of ascorbic acid contained in green tea leaves. Ascorbic acid (aka Vitamin C) is very sensitive to differences in environment so it is also a good indicator that other beneficial components of tea will be breaking down at the same time.

Heat

Another component of brewing tea, heat aids in the extraction of tea leaf properties. In an infusion this is definitely desired, but when storing green tea, heat can break down the leaves very quickly. In general, anything over 85F (around 30C) will speed up tea leaf deterioration, easily identified by green tea leaves losing their color.

Green tea stored in a low-temperature pantry or basement should not run into these problems, but a kitchen cabinet in the middle of summer can get very hot and will not do your leaves any favors.

If heat is one of the enemies of tea storage, what about storing green tea in the freezer? In concept, the lower temperature will help the leaves stay fresh for longer, but freezer storage for tea brings along a few new challenges.

Any residual moisture within the storage container, whether within the leaves themselves or simply a bit of humid air, may freeze into crystals and break down the leaves even more quickly. In addition, if the tea is going to be removed consistently from the freezer, it may create condensation. This will lead to additional moisture within the package, never a good thing for green tea storage.

If storing in the freezer, it is recommended that you remove all air possible, and think of it as long-term storage instead of something you will reach for every day.

The refrigerator is another option for keeping the temperature of green tea leaves at a low level, but experts and tea lovers everywhere disagree on whether it is a good idea or not. Some tea drinkers report that refrigerator storage will break down green tea leaves even faster, while some anecdotal studies have shown that it is the best balance between freezer and room-temperature storage.

Odors

When considering storing green tea in the refrigerator or anywhere else, it is important to know that green tea leaves, while having their own fragrant scent, also easily pick up external smells and odors. There are normally a lot of unsealed food products in a refrigerator, and your tea will absorb any odors that those may emit.

This is also true for a pantry, basement, or anywhere raw root vegetables are stored. Green tea leaves love the smell of onions and garlic and will share that scent with you when you are brewing your tea.

Oxygen

Green tea is produced without oxidation, leaving the natural leaf color intact. After packaging, green tea leaves are highly susceptible to oxidation, which will change the color of the leaves brown after enough oxygen exposure. This will also cause the leaves to lose flavor.

Light

It makes perfect sense that ultraviolet rays from sunlight will speed the deterioration of green tea leaves, but indoor light can as well. Tea leaves contain chlorophyll, giving them their natural green color when they have reached their prime. White tea is named from the lighter color of the young buds that have not turned as green.

Chlorophyll reacts to both natural and indoor light. As light excites the chlorophyll, it will become reactive and start chemical reactions that will break down the tea leaves.

Help Green Tea Last Longer

In order to help green tea leaves last as long as possible, do everything you can to remove or mitigate the five factors listed above. When properly stored, some green teas may last up to three years before a significant loss of flavor, but that will also depend on the quality of the leaves and the processing method.

Additionally, green tea bags that are sealed in their own foil pouches can last an incredibly long time. With very little space in the small pouches for oxygen or humidity to accumulate, we have seen some tea bags retain their flavor for over four years.

Many packaged green teas arrive in resealable pouches with either a metal or plastic liner, both of which help to reduce any interaction with outside light, moisture, odors, and oxygen. It will still be important to keep the green tea in a cool location, and be sure that as little water or oxygen as possible finds its way into the package after opening.

When buying loose leaf green tea, sometimes the tea store will package them in similar resealable packaging, but this is not always the case. Lined resealable pouches are available online in different sizes. Be sure to look for versions that are opaque – clear pouches will allow light in.

Another option for green tea storage is an air-tight tea storage container. You will not be able to remove as much oxygen from them, but they are better for the environment. Look for containers that have the following properties:

• Create an air-tight seal
• Do not absorb odors
• Easy to wash
• Blocks light 

Conclusion

While green tea may have a relatively short shelf life compared to other types of tea leaves, proper storage can preserve the leaves for a year and a half or more. Try to buy smaller amounts of green tea at one time to not fall into the trap of having too much tea in storage, and you won’t run into this problem. And if all else fails, drink it!