Cornell University Study Shows Water Composition Impacts Tea

Drink water purification filters. Different tap water filtration systems for home water treatment. (Getty Images/esvetleishaya)
When good tea tastes bad, it is generally because of the water composition or the temperature and number of minutes that you heat it in brewing. Water controls the entire chemistry of transforming a tea leaf into a beverage. A recent Cornell University study adds just one more instance to the many examples, some of which you have surely experienced. That elegant white tea that tasted so good, for instance, when you sampled it in the tea store but was so flat back home. The store used spring water and you tried distilled, which is more pure—too pure. (It lacks minerals and salt.) The Cornell researchers found that green tea brewed with bottled water tasted more bitter but released a greater amount of health-contributing anti-oxidants. Tap water made it sweeter and the 100 consumers in the panel judged it as tasting better. A Cornell professor of food science made the comment: “If you’re drinking green tea for its health properties, then you should be using bottled water. If you’re drinking tea for taste, tap water is better.” What are you drinking tea for? For just a wet and warm boost from a tea dust bag, then the water is a peripheral issue. But if you want to get the best from fine teas’ flavor and aroma, then it’s worth spending as much time on choosing your water sources as you do on picking out a teapot or kettle. Factors to consider:
Reverse osmosis water purification system. (Getty Images/DmitriMaruta)
Hardness: the calcium and magnesium in the water, measured in parts per million. Too high and the tea will taste flat and lack fullness of flavor. Acid/alkalinity: Pure water has a pH level of 7 (the acronym stands for Power of Hydrogen.) The lower the pH, the closer it is to battery acid. TDS (totally dissolved solids): Too low and the water lacks minerals that aid in health, too high and the likely cause is harmful overload, possibly including plastics, chemicals, and industrial waste. There are five options:
  • Bottled mineral spring: The best quality of water when it is certified as coming direct from a mountain spring. Natural absorption of minerals with no other solids, ideal pH and hardness. Very much the connoisseur’s pick. But expensive, criticized as environmentally damaging.
  • Reverse osmosis: A purification technology that forces water through a membrane to remove molecules, ions and solids from even waste water. Relatively expensive for home investment ($300 on up). The preferred system for many fine tea stores.
  • Carbon filter: Probably the most popular choice for frequent specialty tea drinkers. Charcoal and coconut shell filters have a long history, especially in Japan. They work well in filtering out undesirable and unhealthy solids while maintaining minerals and salts. Used in pitchers or as an attachment to a faucet.
  • Faucet: Generally, a good enough choice in most regions for occasional tea making. Check the pH using a test strip.
  • Bottled drinking: Varies greatly in quality and truth in labeling; some products are just tap water. Many environmental concerns accompany bottled water, which offers no compelling reason for tea drinkers to adopt it.
Brita Grand Pitcher (Photo/brita.com)
Distilled is not a good choice; you need the minerals. Overall, the most cost-effective choice for tea lovers seems to be faucet water poured through a carbon filter pitcher with a first-rate mountain spring water for those really special teas. Brita is the best-known filter system and Volvic’s spring water from the Auvergne in France is preeminent in the consumer market.