Brewing a cup of tea can be a great way to help you relax after a stressful day. But sometimes you may forget about your tea. What happens if you fall asleep and leave your tea out? Can you drink overnight tea?

To answer this question, Faktyoxla Lab. did some research.

Tea ceremonies have deep traditional roots in Azerbaijan. A traditional tea ceremony has its own rules and practices that are designed to make the serving and drinking process enjoyable. According to the old tradition, the host has to offer tea to every visitor, even if the visit is supposed to last only five minutes.

Tea is associated with warmth and friendliness, therefore, the tradition says that one should not allow the guest to leave the house without having at least one cup of tea.

Tea in Azerbaijan is served freshly brewed, hot and strong. It typically has a bright color and is served in crystal or any other glasses or cups. Azerbaijanis often use traditional armudu (pear-shaped) glass. Tea is served continuously when there are guests or when there is an interesting conversation.

If you leave out your tea for longer than a few hours, you will taste a difference in taste. The tea will lose some of the floral and vegetal notes, but also the bitterness that may be present.

This is for the same reason that black tea tends to be less bitter than green tea. The oxygen in the air can oxidize some of the chemicals present in the tea.

With the age of your tea, there will not only be oxidization going on. It is also possible that the tea could be containing bacteria and mold. The teacup can provide a great environment for microorganisms like these to grow.

Both bacteria and mold can seriously impact your health if you drink overnight tea that has gone bad. Both bacteria and mold need only be present in tiny amounts to allow for rapid growth. The brewing methods influence how long it takes for the microorganisms to ruin your tea.

Bacteria can grow quite quickly in a warm and moist environment. If your tea leaves smell acidic or taste off, there is a good chance this is due to large numbers of bacteria being active and reproducing. 

You can use the tea as natural fertilizer for your plants. As tea is made from plant material, many of the nutrients necessary for plant growth are present in your leftover tea. Even though you shouldn’t drink it, the plants will happily absorb the nutrients. Be sure to dilute the tea first, though. You do not want highly concentrated tea to harm your plants.

Overnight tea usually refers to tea made the night or day before. Tea that has been sitting around for way too long is also referred to as overnight tea as well.

When tea sits around for too long, a substance called TP (tea polyphenol) that it contains will start to oxidize, this darkens the tea. A great example would be green tea, its color will turn from bright green to yellow when put in a high heat environment. This is because when TP oxidizes, non-toxic and harmless chemicals [technical term alert] such as theaflavins, thearubigins and theabrownins are also produced.

However, it will become cold when you just leave it there (or put in the refrigerator). Drinking cold tea does provoke our digestive systems, this is because of the heavy doses of stimulants such as theophylline and caffeine that cold tea contains, which will cause negative impacts on our health. Surely, tea becomes undrinkable too when it starts to turn a little bit sour, so please be extra cautious in hot weather! A lot of vitamins are also lost when tea sits around for too long, for example, vitamin C and vitamin E. Additionally, the proteins and sugars in the tea attract bacteria and mycete.

In a nutshell, drinking overnight tea not only doesn’t provide you with any vitamins but also will infect your body with bacteria. So please don’t!