What the Science Says About Temperature
The conversation around hot drinks and health isn't about the beverages themselves, but their temperature. In 2016, the World Health Organization's International Agency for Research on Cancer (IARC) made a significant classification. They concluded that
drinking beverages hotter than 65 degrees Celsius (149 degrees Fahrenheit) is "probably carcinogenic to humans". This conclusion was based on studies from regions where it's common to drink tea or other infusions at around 70°C. The key takeaway from the IARC is that the risk appears to be linked to the temperature itself, not the specific contents of the drink, whether it's tea, coffee, or something else. It’s the thermal injury, a type of burn to the food pipe, that raises concern.
Understanding Thermal Injury
So, what happens inside your body when you sip something that’s scalding hot? Repeatedly exposing the delicate lining of your oesophagus to excessively high temperatures can cause recurrent, minor burns. Think of it like a series of small sunburns on your skin. Over time, this constant damage forces the cells in the area to repair and regenerate more frequently. This process of chronic inflammation and rapid cell turnover can increase the chances of errors occurring during cell division, which may eventually lead to the formation of cancerous cells. Studies have shown that consuming very hot drinks can cause visible damage, such as inflammation and the formation of a whitish layer called a pseudomembrane on the oesophagus lining. A recent large-scale UK study involving nearly one million people found that those who reported drinking 'very hot' tea had a threefold greater risk of developing oesophageal squamous cell carcinoma compared to those who drank it 'warm'.
How Hot Is Too Hot?
The critical threshold identified by researchers is 65°C (149°F). To put that into perspective, coffee and tea are often served in cafes at temperatures between 71-82°C (160-180°F). Most people, however, find it uncomfortable to drink liquids above this 65°C limit, as it is close to the human pain threshold. A study in Iran, which measured temperatures directly, found that drinking more than 700ml of tea per day at 60°C or higher was associated with a 90 percent increased risk for oesophageal cancer. The ideal drinking temperature, which balances flavour with safety, is generally considered to be between 54°C and 60°C. The good news is that you don’t need a thermometer to be safe; simply waiting a few minutes for your drink to cool from 'scalding' to 'pleasantly hot' is enough.
A Note on Indian Beverage Habits
In India, the culture of drinking 'garam chai' is deeply ingrained. From bustling city streets to quiet village homes, a steaming cup of tea is a symbol of hospitality and a staple of daily life. Often, it's served piping hot, and many have become accustomed to sipping it at very high temperatures. While the research from the IARC primarily focused on tea-drinking habits in places like China, Iran, and South America, the principle of thermal injury is universal. The risk isn't about the masala chai itself, but the practice of drinking it before it has had a chance to cool to a safer temperature. The key is not to abandon this beloved ritual, but to adopt a small, mindful change. Letting your chai sit for a few extra minutes before you start sipping is a simple adjustment.
Simple Steps for Safer Sipping
Reducing the potential risk doesn't require drastic changes. It's about being more mindful of the heat. First, let your drink rest for a few minutes after it’s poured. What feels 'scalding' right away will likely be a much safer and more pleasant temperature in three to five minutes. Second, add a splash of cold milk or water to quickly bring the temperature down. This is a common practice that also happens to be a smart safety measure. Third, take small, tentative sips at first to test the temperature instead of a large gulp that could cause a more significant burn. Finally, be cautious with microwaved liquids, which can heat unevenly and have hidden hot spots. Stirring well can help distribute the heat more evenly. By making these small adjustments, you can continue to enjoy the comfort and flavour of your favourite hot beverages without the associated thermal risk.
