Drinking old tea is unlikely to make you seriously ill in most cases, but safety depends entirely on what kind of “old” you’re dealing with. A forgotten cup from this morning is a different situation than a pitcher that’s been in the fridge for a week, and both are different from a box of tea bags that expired last year. Here’s how to think about each scenario.
Brewed Tea Left at Room Temperature
Brewed tea sitting on your counter is the riskiest form of “old tea.” Bacteria multiply rapidly between 40°F and 140°F, and a cup or pitcher of tea at room temperature falls squarely in that zone. The CDC recommends not holding brewed tea at room temperature for more than 8 hours. After that window, bacterial levels can climb high enough to cause stomach upset or food poisoning.
Tea that has been brewed using the sun tea method, where you leave a jar of water and tea bags in sunlight for hours, carries an even higher risk. The water never gets hot enough to kill microorganisms that may be present on the tea leaves. Since 2011, the CDC has strongly discouraged making sun tea for exactly this reason. If you want iced tea, brew it with water heated to at least 195°F, steep for three to five minutes, then cool it down.
How Long Brewed Tea Lasts in the Fridge
Refrigeration buys you time, but not unlimited time. The CDC’s official guideline is that iced tea should be stored in the fridge for no more than 8 hours. In practice, most tea drinkers find that brewed tea tastes best within the first day and stays reasonably good for three to four days when refrigerated. Iowa State University Extension recommends consuming refrigerated tea within three days as a food safety guideline.
The taste issue and the safety issue are two separate clocks. Flavor degrades before the tea becomes dangerous, so staleness is your early warning system. The beneficial compounds in tea also break down over time. At refrigerator temperatures (around 4°C), antioxidants called catechins remain fairly stable for 24 hours. At room temperature, degradation accelerates significantly, with losses of 67% or more within a day depending on the tea’s acidity.
To get the most out of refrigerated tea, store it in a clean, sealed container. Sanitize your pitcher or jar before each batch. Open containers invite both bacteria and off-flavors from other foods in your fridge.
Signs That Brewed Tea Has Gone Bad
Trust your senses. Tea that has spoiled often develops a sour or otherwise “off” smell that’s distinct from the normal tannic bitterness of over-steeped tea. You may also notice a thick, syrupy, or “ropey” texture when you pour it, which signals bacterial colonies have been growing. Any visible film on the surface, cloudiness that wasn’t there before, or mold floating on top means it’s time to dump it.
If the tea smells fine, looks clear, and tastes normal, it’s probably fine. But if it’s been sitting out for a full day or in the fridge for more than three or four days, the safest move is to make a fresh batch.
Expired Dry Tea Leaves and Tea Bags
Dry tea leaves that are past their “best by” date are a completely different story from old brewed tea. Dried tea that has been kept dry will not spoil. The date on the box is about quality, not safety. Over time, the flavor fades and the beneficial plant compounds degrade, but the leaves themselves don’t become toxic just from aging.
According to researchers at Tufts University, properly stored tea can maintain its flavor and nutritional value for up to two years. After that, you’re drinking something increasingly bland, but not harmful. The key phrase is “properly stored.” That means an airtight container, kept away from heat, moisture, light, and strong odors. Storing tea next to the stove or above the sink, where steam and heat are constant, accelerates the breakdown.
The enemies of dry tea are, in order of importance: moisture, heat, light, and air. If humidity exceeds about 70%, tea leaves can absorb enough water from the air to support mold and bacterial growth. Temperatures above 86°F (30°C) speed up oxidation, dulling the color and flavor. UV light breaks down pigments and aromatic compounds. And exposure to air allows all of these processes to happen faster.
When Old Dry Tea Becomes a Real Concern
The one genuine health risk with old dry tea is mold contamination, specifically toxic compounds called mycotoxins that certain molds produce. A review published in the journal Toxins found that tea leaves can become contaminated with these toxins at any stage, from the field to your pantry. Poor storage conditions, especially dampness, are the main driver.
Black tea samples from multiple countries have tested positive for various mycotoxins, though usually at low levels. Pu-erh tea carries higher risk because its manufacturing process involves deliberate microbial fermentation, which can go wrong. In one Chinese study, all 70 Pu-erh samples tested contained detectable levels of multiple mycotoxins. For standard black, green, or herbal teas stored in normal household conditions, the risk is much lower.
If your dry tea shows any visible mold, has a musty smell, or has been stored in a damp environment, throw it out. If it’s simply old and was kept in a sealed container in a dry cupboard, it’s safe to brew. It just won’t taste like much.
How to Store Tea for Maximum Freshness
- Transfer to airtight containers as soon as possible after purchase. The original packaging is often not airtight once opened.
- Keep it cool and dry. A cupboard away from the stove, dishwasher, and sink is ideal. Avoid spots that get direct sunlight.
- Avoid temperature swings. Frequent fluctuations between warm and cool accelerate degradation more than a steady, slightly warm temperature does.
- Don’t refrigerate dry tea unless you can guarantee the container is truly airtight. Fridges are humid environments, and condensation when you take the container in and out introduces moisture.
- For brewed tea, cool it quickly after brewing, transfer to a clean sealed pitcher, and refrigerate. Use it within three days.