Brewed tea made at home or in a tea shop has a limited amount of time where it will still be good to drink. The first sign that tea is going bad is that the flavor will change, or even disappear. In stages after that, the tea will go from mildly unpleasant all the way to unhealthy.
How Long Is Brewed Tea Good for?
Brewed tea is good for about 4 hours when left at room temperature. After that point, the flavor will change. After around 8 hours, bacterial growth will make the tea unhealthy to drink. If refrigerated, however, brewed tea is good for 2-5 days.
It can be hard to judge when a tea goes “bad” but in our opinion, when the chemical bonds of the flavors and aromas start breaking down, tea is not good anymore. That will usually happen well before the tea becomes unsafe for consumption, so it is up to the individual to decide whether that cup is worth drinking or not.
The Effect of Temperature on Brewed Tea
Time and temperature are the two main factors when it comes to judging how long food or drink is good for. There is a “danger zone” referenced in cooking which tells us the optimal range for bacterial growth. This is between 40°F – 140°F, where hot food should be kept above 140° and cold food, or food in storage, should be kept under 40°.
Brewed tea, since it can be considered “cooked” food, could be kept above 140°F to prevent bacterial growth, but this would cause the flavor and scent to dissipate even faster than if it were at room temperature. While hot water is needed to extract the essence of the tea leaves, continual heat breaks down the chemical chains needed for taste and aroma.
Evaporation also plays a role in changing the taste of brewed tea when kept hot. Many of the pleasant notes that you smell in the steam of tea is actually being lost from the cup, and after a few hours that can have an effect. Keeping hot tea in a vacuum-sealed container with a lid will both keep the tea warm and reduce the loss of flavor from evaporation.
Oxidation and Brewed Tea
In addition to bacteria, simple oxygen can have a role in making tea go bad. Oxidation, the process that tea leaves go through for black and oolong teas, can also occur after tea is brewed. This makes the tea break down more quickly, so if you can, put a lid on the tea if it will be sitting out for a little while.
You will notice that the color will start to change as the tea oxidizes, getting darker and adding a brown tint to teas that are possibly supposed to be amber or green. Bitterness will actually decrease, and any complex flavors will have been muted or may even disappear completely.
Oxidation will generally occur before older brewed tea is deemed unhealthy. Oxidized tea is not necessarily bad, but it is very rarely good.
Cold Tea Keeps for Longer
Instead of keeping brewed tea hot to try to preserve it, refrigeration works well to keep tea from going bad. Cold temperatures under 40°F inhibit bacterial growth and also help preserve the taste.
If you already know you are going to save your brewed tea for more than a few hours, it is important to get it into the refrigerator as soon as possible. Do not leave your tea out for just under 4 hours, then put it in the refrigerator, and expect it to taste just as good as when you first brewed it.
For small amounts of tea, up to a pint or so, you can usually put it into the refrigerator immediately after brewing. Do not attempt this with a large amount of tea, a full pot for instance. The added thermal mass can bring the temperature of the entire refrigerator up, both making it work harder, and also possibly increasing the temperature to dangerously high levels for raw food.
Doing More to Preserve Freshness
Tea in the refrigerator, as already mentioned, can last from 2-5 days before it goes bad. With a few additional tips you should be able to get the refrigerated life of tea up to that 5-day range instead of sipping a bad cup of tea at 2 days.
- Cover your tea while it is in the refrigerator – Stray odors and bacteria can float around in your fridge. Since the experience of tea is based on subtle scents and flavors, you do not want it to pick up any aromas from things like leftovers or old vegetables. Make sure you place it in a sealed container.
- Cold-brew your tea – While this may only be appropriate for iced tea, tea that has been cold brewed stays good for longer than tea brewed with hot water, probably around a week instead of just 5 days.
- Do not add sugar to your tea before refrigerating – Sugar helps bacteria grow by providing it with glucose, which a lot of different bacteria like E Coli happen to love. While overloading tea with sugar can inhibit bacterial growth, like in jelly or jam, the small amount of sweetener normally added to brewed tea just acts as food for bacteria.
- Consider freezing your brewed tea – When you know you will not be able to finish your tea for a few days, freezing is always an option. Frozen tea ice cubes are perfect for making iced tea without worrying about diluting the flavor with regular ice. You can also preserve the flavor of tea leaves by making one large batch and freezing it.
Can Old Brewed Tea Make You Sick?
Yes. In the right conditions, or even with just enough time, old brewed tea can give you food poisoning. Coliform bacteria may be on the tea leaves used to brew, and the temperature of the water used to brew may not be hot enough to kill it.
Does Brewed Tea Need to Be Refrigerated?
If you plan on not drinking your tea for over 4 hours, you should refrigerate it. This will preserve your tea for between 2-5 days under the right conditions. Be sure to keep it in a sealed container.
Is It Safe to Drink Tea Left Out Overnight?
Overnight tea in some cases may be safe to drink, but it can be difficult to judge. We do not recommend drinking tea left out for over 8 hours, but tea left out in a cold house for a little over that amount of time would probably be ok.
Smell the tea first, and if anything seems off, dispose of it immediately.
Brewed tea is good for a little more than a few hours at room temperature. If you really want to keep that leftover pot, refrigerating or freezing it will help preserve it for much longer. Depending on the price and quality of the tea, sometimes we will want to get the most out of it. If this sounds like you, be sure to read the tips above for keeping brewed tea good for as long as possible.
Scott is the founder of TeaMinded. He enjoys tasting and discovering teas from across the globe, with green teas and ceremonial matcha from Japan being among his favorites. He’s grateful to be immersed in the tea community, always learning and sharing along the journey.