How Long Does Green Tea Last?

Two different questions hide in this one. Dry leaves mostly lose quality over time. A brewed cup has a real food safety clock. We’ll take them one at a time.

Does dry green tea expire?

Not the way milk does. Two Leaves and a Bud, a tea seller, says its best-by date is set from the day the tea is packed and marks when the tea tastes best. It says tea slowly loses flavor, but properly stored tea won’t spoil, even after the package is opened.

What changes is the tea itself. A 2026 review of tea storage research says catechins oxidize, chlorophyll breaks down and aroma fades. Leaves turn from green toward yellow or brown, the cup darkens and the flavor goes flat. Heat speeds this up. For finished green tea, each 10°C (18°F) rise in storage temperature raises the rate of quality loss by 3 to 4 times, according to the review.

How long does it keep its best quality?

Source	What it says
2026 tea storage review	Green tea at room temperature with no preservation: about 3 to 6 months
2026 tea storage review	Cold storage in the tea industry adds about 6 to 12 months for premium green tea
Two Leaves and a Bud	Best by the printed date, which is set from the packing date

These figures differ because the conditions differ. The review’s 3 to 6 months is for tea kept at room temperature with no preservation steps. Good packaging slows the decline. There’s no single number for every tea, so use the date on your pack.

Does green tea expire if it’s sealed?

A sealed pack ages more slowly, but the date still applies. The review says aluminum foil bags have an outstanding barrier against moisture, and Bigelow wraps each of its green tea bags in a foil pouch. Once you open the pack, air, light and humidity start working on the leaves.

How can you tell dry green tea has gone bad?

• Stale: weak smell, flat taste, dull or brownish leaves. This is a quality problem. Two Leaves and a Bud says properly stored tea doesn’t spoil.
• Moldy: tea can grow mold if it gets damp. The review says a moisture content above 7% in dried tea substantially raises the risk of mold, and tea readily absorbs water from humid air. If you see mold, throw the tea out.

How should you store dry green tea?

• Two Leaves and a Bud advises an airtight container in a cool, dry place away from strong odors. The review adds that light breaks down tea’s pigments, so an opaque container helps.
• Keep it away from the stove and sunny windows.
• Be careful with the fridge. The review says tea taken out of cold storage can pick up condensation, so cold storage needs airtight, odor-proof packaging.
• Pick the container with care. The review ranks foil bags and sealed metal cans among the better options and paper cartons and thin plastic bags among the weaker ones. One test in hot, humid, bright conditions ranked a plain tin can among the worst, so a tin works best in a cool, dark cupboard.

How long does brewed green tea last?

Where	How long	Source
Room temperature	No more than 8 hours	Iowa State Extension
Refrigerator, 40°F or below	Drink within 3 days	Iowa State Extension; FDA for the fridge temperature
Sun tea	Skip it	Iowa State Extension

These are extension guidelines for brewed tea, not a federal limit. Iowa State also suggests adding sweeteners and flavorings after brewing. It says the CDC has highly discouraged sun tea since 2011, because sun-warmed water doesn’t get hot enough to kill bacteria.

Why the limits? Tea leaves aren’t sterile. In an FDA lab study, Salmonella added to dried green tea showed little decline over 6 months when stored dry at 25°C (77°F), and every brewed tea tested supported its growth. That was a deliberate contamination test. A 1996 CDC memo, as summarized by Food Safety News, said no outbreaks had been reported that were clearly linked to tea. It still advised brewing at 195°F, cleaning equipment daily and storing iced tea no longer than 8 hours.

Iowa State says the CDC and the National Tea Association recommend steeping at 195°F for 3 to 5 minutes, which it says is enough to kill microbes. That’s hotter than most green tea flavor advice, so if you brew cooler for taste, watch the clock and keep the tea cold. The FDA’s two-hour rule for perishable foods is stricter: no more than 2 hours at room temperature, or 1 hour above 90°F. The FDA’s examples are foods like meat, eggs and leftovers, and it doesn’t mention tea. If you want the cautious choice, especially in a hot kitchen, use the shorter limit.

Flavor fades too. In a 2026 study of commercially made green tea drinks, color change and a cooked off-flavor grew the longer and warmer they were stored. That study looked at quality, not safety.

If your tea smells off, or you see anything growing in it, pour it out. Cloudy iced tea has its own cause: Iowa State says tannins released during steeping make it cloudy, and cooling the tea gradually helps prevent it. For big batches, see how many tea bags make a gallon. More brewing and storage guides are in how to brew green tea.