Coffee that is too hot can increase the risk of cancer, what temperature should you drink it at to be safe?

Drinking a steaming cup of tea or coffee may be relaxing and pleasant. However, it can also affect your health, increasing your risk of esophageal cancer.

Why drinking tea and coffee that is too hot causes cancer ?

In 2016, the International Agency for Research on Cancer (IARC) classified drinking very hot drinks, those above 65°C, as possibly carcinogenic. The report found that it was the temperature, not the drink itself, that was the harmful factor.

Previously, studies in South America showed that drinking a lot of maté - a traditional herbal drink often consumed at around 70°C - caused a higher risk of esophageal cancer.

Similar studies in the Middle East, Africa and Asia have also strengthened the link between drinking very hot beverages and the risk of esophageal cancer.

This year, a major study of nearly half a million adults in the UK confirmed that drinking lots of very hot drinks like tea and coffee is linked to esophageal cancer, Science Alert reports.

Research has found that people who drink eight or more cups of very hot tea or coffee a day have a nearly six times higher risk of developing esophageal cancer than those who do not drink hot beverages.

Drinking very hot drinks can damage the cells lining the esophagus, and it is believed that over time this can lead to the development of cancer. Researchers first hypothesized this link nearly 90 years ago.

How to drink hot drinks safely?

The risk of cancer may depend on how much hot liquid you drink at one time and how fast you drink it. It appears that drinking large amounts of hot liquid at one time is more likely to cause damage to the esophagus.

Researchers measured the temperature inside the esophagus of people drinking hot coffee at different temperatures. They found that sip size had more of an effect than the temperature of the beverage.

A very large sip (20 ml) of coffee at 65°C can increase the temperature inside the esophagus by up to 12°C. Over time, drinking large sips can cause cell damage.

An occasional sip of coffee at 65°C is unlikely to cause any long-term problems. But over many years, drinking large amounts of very hot drinks can increase the risk of oesophageal cancer.

Hot drinks such as takeaway coffee are sometimes served at very high temperatures (around 90°C) to "compensate" for cooling.

A study from the US calculated the ideal temperature for coffee is 57.8°C, both to avoid esophageal damage and to preserve the taste and aroma. The temperature of a hot drink can drop by 10-15°C within five minutes.