Is Overnight Tea Safe To Drink? 3 Ways

Unfinished tea may harbor poisonous concerns. If you’re wondering, “is overnight tea safe to drink or can you leave tea out overnight?” find out in this article.

Is overnight tea safe to drink
Unfinished tea may harbor poisonous concerns

Have you ever had a sudden urge to chug down the unfinished tea you left out the night before? Well, before that cuppa touches your mouth, you might wonder, “Is overnight tea safe to drink, or can you leave tea out overnight?” The simple answer is to avoid it.

When tea is left overnight for over eight hours, a substance called TP (tea polyphenol) will start to oxidize, which darkens the tea. Most vitamins, such as C and E, also disappear. At the same time, bacteria can develop.

How Long Does Brewed Tea Last At Room Temperature?

According to the Center for Disease Control and Prevention, brewed tea is best consumed within eight hours, as after this point, bacteria will begin to flourish. The longest time an unfinished tea lasts is up to twelve hours, given proper care. Overnight tea can last up to five days in the fridge and six months in a freezer.

Why Is It Unsafe To Drink Overnight Tea?

The Growth Of Microorganisms In Overnight Tea

Overnight tea makes a perfect environment for harmful bacteria and mold to grow. However, the rapid growth of bacteria and mold also fluctuates depending on the warmth and humidity, meaning they grow a lot quicker in warm and moist environments.

Is Overnight Tea Safe To Drink?
They grow a lot quicker in warm and moist environments.

The good news is that it’s very easy to detect if your tea has gone bad. If it smells acidic, changes colors, and the taste is off, dump it and brew a new cup.

Overnight Tea Is Oxidized

The taste and smell of brewed tea change when left outside for a few hours, let alone overnight. You will notice that its floral and vegetal notes will slowly fade away. The color will also darken and is even more visible for green and white tea.

Is It Safe To Reheat Overnight Tea?

If you absolutely must, reheating overnight tea may kill bacteria and mold. However, ensure you detect no sign of mold or bacteria already developed. The minimum temperature to reheat overnight tea is at least 190.4°F (88 °C.) 

Only reheat if it’s been sitting out less than eight hours. The flavors will likely change due to the heat; this may be more apparent with some kinds of tea than others.  Some teas will lose their flavor profile and become less complex as they’ve already lost the volatile compounds that contribute to the typical flavor profile.

Cold-Brewed Tea Is Safe To Drink

If there is one type of tea that can be consumed overnight without giving in to the attack of bacteria or mold, that’s a cold brew. Cold-brewed tea is usually made by steeping it for at least half a day or overnight in the fridge using a bottle with an integrated filter. To this point, some people will argue that the temperature is not high enough to kill off bacteria as with a hot brew. 

The scientific grounding behind a cold brew comes from the cold temperature that slows the growth of bacteria and mold. You should still store your cold brew in the fridge and drink it in a timely manner to be on the safe side.

Can You Drink Overnight Sun Tea?

Sun tea is brewed by setting the tea in a clear container in the sun for multiple hours, preferably four hours at best. When the temperature outdoors rises, the extraction happens faster, providing a ready-to-drink cuppa without needing a stovetop or kettle.

If you plan to store sun tea for later use, keep it in the sun for three hours and put it into the fridge. Sun tea will be dangerous to consume if left outside overnight since the heat is not high enough to kill bacteria in the water.

Most sun tea can only go to about 129°F (54°C). Meanwhile, the proper heating temperature should reach 212°F (100°C) to kill bacteria.

The Best Ways To Preserve Overnight Brewed Tea

Brewed tea in a mason jar
Store it in a mason jar and cover it with an airtight lid
  • Don’t leave your cuppa outside and open up all night. Store it in a mason jar and cover it with an airtight lid to make sure no bacteria or harmful microorganisms in the air will affect the brew.
  • Keep it unsweetened if you haven’t planned to drink it right away. The higher sugar content in tea allows bacteria to grow a lot faster.
  • Unfinished tea can be kept in the fridge to maximize its shelf life. Fridge-stored tea is expected to last up to five days in an airtight container. Covering the tea will protect it from unwanted smells brought by other items in the fridge.

How To Benefit From Unfinished Overnight Tea

Dumping unfinished overnight tea seems like a huge waste for many people, especially if that’s a high-quality purchase. In this case, the easiest way to give it another life is to use it as a natural fertilizer for plants.

Overnight tea still contains many nutrients the plants need, such as polyphenols. Other than that, you can also use overnight tea to boost compost and deter pests.

Tea is one of the best things to remove any unpleasant odors. I usually spray it all over the table after a meal, and the smell goes away after two or three swipes. Other than that, overnight tea bags can be used as a mouth rinse and soothe sore tongues and inflamed skin.


  • Oanh Nguyen

    Born and raised by a traditional mama-barista, Oanh is a typical Viet coffee aficionado who would spend her entire precious Sunday showing you how to categorize coffee beans just by the looks and smells. She enjoys writing about everything drinks-related while sipping her favorite rosebud tea. Find Oanh on LinkedIn.