An On-Going Debate: Is Brewed Tea Still Good Overnight


You love tea, right? Just like many tea lovers, perhaps you brew more tea than you can drink at once. Consequently, you’ll have to leave some and drink later. Everyone wants to maximize value for their money and so, throwing it away would be a less preferred choice for a left-over brewed tea. Just before your supper, you might want to take a cup of tea or several to maximize the intake of nutrient intake and absorption of iron from the meal. Besides, some people tend to drink tea as they enjoy their favorite night or evening TV shows/movies-just for fun.  If some tea remains, many people will keep it overnight to drink it in the morning.

There has been an ongoing debate regarding the health impact of brewed tea that has been sitting around overnight for later consumption.  Will it be still drinkable after sitting for too long? Is it true that brewed overnight tea’s poison is like a snake?

 In this article, we’ll explore various facts about overnight tea and finally advise you if it is still good if drank after sitting around the whole night.

What happens when brewed tea stays overnight?

Tea contains a substance known as tea polyphenol (TP). When brewed tea sits around for a long time, say overnight, TP starts to combine chemically with oxygen and water (in a process called oxidation) and this makes it to appear darker.

In case of green tea, you’ll notice that its color changes from light green to yellow when exposed to high heating. This happens because the oxidation of TP results in the production of other chemicals like theaflavins, thearubigins and theabrownins. Fortunately, these chemicals are not toxic, thus harmless. They just make your tea stronger. However, steeping tea for too long is unhealthy as the tea stain which results from the oxidation can have plumbum, arsenic as well as mercury.

If such tea is left to sit for too long, it will form a layer of brown substance. Drinking such tea will lead to the blocking of the digestion as well as the absorption of nutrients in your body.  Therefore, in case you leave your tea for a long time and then you see it having a brown layer, you shouldn’t drink it for your health’s sake.

The major issue with overnight tea is that it can attract the growth of bacteria and mycete because of its protein and sugar elements. That’s why you are likely to see brewed tea appearing murky or moldy if left to sit for too long. If you happen to drink it, there’s a possibility that you’ll be ingesting some bacteria and this puts you at a risk of developing an array of health issues. Therefore, it is advisable that you avoid drinking tea that has stayed for a long time after brewing.

Also, the longer tea stays after brewing, the more it loses lots of vitamins, especially vitamin C and vitamin E. Therefore, overnight tea lacks as many essential vitamins as those in freshly brewed tea.

Therefore, drinking overnight tea doesn’t only increase your chances of getting bacterial infections but also lacks vitamins which fresh tea offers and can cause the obstruction of nutrient absorption and digestion in your body.  Therefore, please avoid drinking stale tea.

Can overnight tea cause cancer?

Some rumors have been going round claiming that overnight tea produces nitrate, a chemical which is seen as a possible cause of cancer. As such, the proponents of this myth claim that drinking overnight tea can lead to cancer.

 But it this true? The answer is no.

Overnight tea, whether staled or not, can’t cause cancer. A series of experiments that have been conducted to shed more light on this issue indicates the likelihood of overnight of having nitrate but the concentration is too low to have adverse effects such as cancer to people. Therefore, in case you decide to drink brewed tea that has sit for a long time, you shouldn’t worry about possible cancer risk.  

What if brewed tea is stored in a refrigerator?

Unlike the tea that has been left out for long at room temperature, overnight tea that’s stored in a refrigerator can be refreshing, especially on a warm day. According to a study done by Centers for Disease Control and Prevention (CDC), brewed tea that has been iced is healthy to drink as long as it remains in the fridge for not more than 8 hours and consumed within one day.  If you drink it afterward, you’ll find it tasting weird as some flavors have been lost. It can even be fermented, especially if you had added some sugar or fruit to it.

Unlike warm overnight brewed tea, the water in cold brewed iced tea isn’t warm enough to support the growth of bacteria. Therefore, you aren’t at any risk of a bacterial infection as a result of drinking cold-brewed iced tea as long as you don’t overstore it in the fridge, put it in contaminated vessels, or take too long to drink it after getting it out of the fridge.

Remember to use clean, sterilized brewing and storage containers should you decide to store your brewed tea in the refrigerator. This will reduce the possibility of bacterial contamination and help in the preservation of the good flavor of the tea.  Also, storing your iced tea in air tight vessels in your fridge helps in the maintenance of the desired flavors of the tea and prevents the absorption of the flavors of other items in the refrigerator by the tea.

Parting shot

Overnight tea isn’t good for your health if it isn’t iced and used within the appropriate period. In case you leave your brewed tea for some time and then you notice ropy strands, brown layer, sour smell or weird flavor in it, don’t drink it. There’s a high possibility that it has bacteria and drinking it will put you at risk of bacterial infections. Nevertheless, brewed overnight tea can’t cause cancer even if it is stale or not.  If you have to drink overnight brewed tea, ensure that it’s been stored in a fridge in a clean and sterilized container for a maximum of one day. Besides, keep the tea liquid separated from the tea leaves to avoid developing nutrient absorption and digestion issues in your body.

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