Can You Drink Tea That Has Been Left Out Overnight

By July 17, 2017

tea benefits

Can you drink tea that has been left out overnight? Is it bad for you health? 

The overnight tea actually means the tea that has been relatively sit out long. It’s not necessarily left out overnight, as long as for a  long time. The primary problem of  leaving tea out overnight is that bacterial can start to grow. Besides, most of the Vitamin will get lost and the tea polyphenol will get oxidized. So if you see mold or if the tea becomes murky, don’t drink it. If you refrigerate the tea overnight in the well sealed container (cold brew tea is made in this way), you can drink it. Actually, the dangers of overnight tea is only limited to the stale tea. The overnight tea which is not staled has many health benefits. 

Now, let’s dig in and continue to its effects on  health condition. 

loose leaf tea

Actually, it is sometimes good to steep tea overnight. (Tips: how long to steep tea?)Why? Steeping tea in the water for a long time will make the brew very concentrated. Some of the elements might start interacting with each other and oxidize forming different combinations, which are beneficial to you. But it is proved that steeping strong tea beyond a certain time is harmful to health, like Puerh, Oolong tea and green tea. What happened if you steep these teas too long

Tea contains  tea polyphenol, which is easily oxidized to tea stain by oxygen in the air and water. Pickaxe, plumbum, arsenic and mercury can be found in the tea stain. If you drink this overnight tea, it will  block the digestion and absorption of nutrients. If you see there is a layer of brown material over your overnight tea, don’t drink it. 

Can overnight tea cause cancer? 

green tea leaf

Most often heard about the dangers of overnight tea will produce nitrite, which may cause cancer. Is that true? No, the overnight tea will not cause caner, whether it is staled or unstaled. According to experiments, there’s a chance that overnight tea may have hihger content of nitrite, but not enough to have bad effects on humans. So, there in no worry that drinking overnight tea may cause cancer.

 All in all, can you drink tea that has been left out overnight? The answer depends. If the tea is not staled, it ‘s OK to drink it. But, do not let it steep and sit out too long, thus it will get staled and bring harmfulness.

Tips: To brew loose leaf tea, I am using this glass teapot with infuser. It is beautiful, and helps me makes a good cup of tea. 

ecooe glass teapot

Learn more: How many times can you use a tea bag?

The 6 Best Teapots in 2017

Tags: Health Tips

Comments (2)



  1. I have a huge ceramic teapot and I make loose leaf tea 2 or 3 times a week. This means the tea can be as old as 3 days. Occasionally I see a clear shiny growth on the surface of the water. I was hoping you could tell me if this means the tea is fermenting or just contaminated with a toxic mold.

  2. I left my loose leaf mint tea I grow overnight outside. I’m wondering if its better to start over and just leave it out for one day. Can you help me? I do not want to get sick. Thank you