It is a common and often confusing experience when a seemingly gentler beverage like tea causes a burning sensation while a stronger drink like coffee does not. This sensation, known as heartburn, is a symptom of gastroesophageal reflux, which occurs when stomach acid flows backward into the esophagus. The explanation lies not just in the overall acidity of the drinks, but in the specific chemical components and how they interact with your digestive system.
Shared Chemical Triggers and LES Function
Both coffee and tea contain compounds that can trigger reflux symptoms, primarily by affecting the Lower Esophageal Sphincter (LES). The LES is a band of muscle that acts as a valve between the esophagus and the stomach, designed to keep stomach contents from moving upward. When this muscle relaxes inappropriately, acid reflux can occur.
Caffeine is a shared component in both beverages that is known to decrease the pressure of the LES, causing it to relax and allowing acid to escape into the esophagus. Studies have indicated that consuming caffeine can significantly lower the basal pressure of the LES following ingestion. This mechanism is a primary reason why individuals who struggle with acid reflux are advised to moderate their intake of caffeinated drinks.
Beyond the chemical effects, the temperature of the beverage also plays a part in irritation. Consuming any hot drink can cause mild irritation to the sensitive lining of the esophagus. This thermal irritation, combined with the LES-relaxing effect of caffeine, establishes the baseline for why either beverage could potentially be a trigger for heartburn.
The Unique Irritation Caused by Tea Tannins
The distinct reason tea may cause heartburn when coffee does not is often linked to its high concentration of polyphenols, specifically tannins. These compounds are responsible for the dry, astringent sensation many people notice when drinking a strong cup of tea. When tannins reach the stomach, they can irritate the delicate mucosal lining.
This irritation may lead the stomach to increase its production of acid as a protective response. Tannins can also interfere with the normal digestive process, potentially slowing down gastric emptying. This increases the time stomach acid has to cause discomfort. The combination of an irritated stomach lining and increased acid production creates a scenario ripe for reflux symptoms.
The concentration of tannins is directly related to the steeping time. A longer steeping time releases a significantly higher amount of these astringent compounds into the water. If you steep your tea for extended periods, you are inadvertently creating a brew with a higher potential for gastric irritation, even if the beverage is chemically less acidic than coffee.
Comparing the Acidity Profiles of Tea and Coffee
While the specific effects of tannins may explain the paradox, the general acidity of the drinks is also a factor. Acidity is measured using the pH scale, where a lower number indicates higher acidity. Most brewed black coffee has a pH range between 4.5 and 5.1.
In comparison, most black teas fall into a slightly less acidic range, with a pH often measured between 4.9 and 5.5. Therefore, coffee is chemically more acidic than most teas, which can make the tea-induced heartburn seem counterintuitive. However, the type of acid matters more than the overall pH for some people.
Coffee contains various organic acids, such as chlorogenic acid, which contribute to its acidity and flavor profile. Tea’s acidity is influenced largely by the tannic acids, which cause the unique irritation described above. This effect is different from the direct acid burn caused by coffee’s lower pH. For some individuals, the physical irritation from tea’s tannins is a more potent trigger than the higher chemical acidity of coffee.
Preparation Methods to Reduce Heartburn Risk
Simple adjustments to tea preparation can significantly reduce the potential for heartburn. Since tannin release is time-dependent, reducing the steeping time is the most effective change to make.
- Aim for a shorter steep of one to two minutes, which allows for flavor extraction while minimizing the release of irritating compounds.
- Avoid consuming tea on an empty stomach, as the tannin and caffeine combination is most likely to cause irritation when the stomach is empty.
- Eating a small snack or having tea after a meal provides a buffer to the stomach lining, mitigating the irritating effects.
- Consider adding a small amount of milk to your tea, as the proteins in milk bind to the tannins, neutralizing some of their astringent effects.
- Ensure the water used is not excessively hot, as mildly lowering the brewing temperature can further reduce the speed and amount of tannin extraction.