Tea Boiling Practices May Impact Acidity, Experts Suggest

As winter settles in across the region, the comforting ritual of a hot cup of tea becomes a daily necessity for many. Yet a popular social media post raising concerns about repeatedly boiled tea has sparked discussions about potential health impacts of this common practice.

The viral Instagram reel by educator Ashu Ghai, which has garnered over 4.6 million views and 86,000 shares, demonstrates how repeatedly boiling tea may increase its acidity. In the video, Ghai measures the pH of freshly prepared tea at 6.5, then shows how after boiling the same tea for an additional 15-20 minutes, the pH drops to 5.9, indicating increased acidity.

Ghai, who runs a science education YouTube channel, explains that prolonged boiling causes tea leaves to release more tannins and polyphenols – naturally occurring acidic compounds. Additionally, as water evaporates during extended boiling, these compounds become more concentrated per unit volume, potentially intensifying their effects.

This practice is particularly relevant at roadside tea stalls and public establishments, where vendors often keep kettles simmering throughout the day to serve a continuous stream of customers.

While large-scale studies directly examining the effects of repeatedly boiled tea on human digestion are lacking, some research does support Ghai’s demonstration. A study conducted at the University of Agriculture in Faisalabad during 1999-2000 found that longer boiling times significantly increased tannin extraction from tea leaves across three commercial brands.

The researchers documented that tannin content increased proportionally with boiling time, while protein digestibility decreased – a combination that could contribute to digestive discomfort. They specifically noted that roadside tea vendors frequently engage in “repeatedly and prolonged boiling of tea for maximum extraction of colour and taste,” a practice they cautioned against.

The study concluded that two minutes of boiling is sufficient for optimal tea preparation, balancing flavor extraction with nutritional safety.

Dr. Anil Arora, Senior Gastroenterologist and Hepatologist at Sir Ganga Ram Hospital, offered insight into the physiological mechanisms at play. “By repeatedly boiling the tea, more chemicals like tannins and polyphenols are extracted from the tea leaves. These compounds can irritate the stomach and, being acidic, may increase acidity,” he explained.

However, Dr. Arora emphasized that the human body has robust systems to manage dietary acids. “The human stomach has huge reserves and multiple mechanisms to neutralize acidity,” he noted, suggesting that for most healthy individuals, repeatedly boiled tea likely poses minimal risk.

The gastroenterologist pointed out that conclusive evidence would require extensive clinical trials comparing the effects of differently prepared tea over several years – studies that would be challenging to design and implement given the multiple variables that influence digestive health, including stress, smoking, anxiety, and medications.

Where the findings may have particular relevance is for individuals with pre-existing digestive sensitivities. “People with a tendency for acidity or suffering from acid peptic disease should avoid repeatedly boiled tea. That is the lesson,” Dr. Arora advised.

The discussion highlights the complex interplay between traditional preparation methods and potential health implications. While the chemistry behind increased acidity in repeatedly boiled tea appears sound, the practical significance for most tea drinkers likely depends on individual health factors and sensitivities.

For the average consumer, moderation in preparation techniques may be the most prudent approach – ensuring tea is properly brewed without excessive boiling time that might compromise both its digestive compatibility and flavor profile.