Water quality’s remarkable impact on green tea

Water hardness is one measure of water quality. This measure expresses the mineral content within the water. Basically, water can be divided into two: when many minerals are present, the water is called hard, and when few are present, the water is called soft. Softer water, with few minerals and a hardness of 120mg/L or less, is best suited to green tea infusion. But water with no mineral content at all, such as distilled water or water purified with a special filter, does not impart intense or pleasurable sensations. Therefore, the best water has at least some mineral content.

Water hardness and green tea infusion

The relationship of water quality to delicious green tea

The two main choices are bottled mineral water or tap water. Here are some points to note for each of these choices. Here we introduce the basic secrets of brewing delicious green tea.

Key points when choosing water, and how to use it

※ Check the label for the hardness level. Choose a suitable type of water with a hardness of at least 120mg/L or less.

Recommendations: 120mg/L or less, non GAS

Soft Water Examples

Luso (PT):8.2mg/L, Deep (NZ):13mg/L, Spa (BE):17mg/L, Deeside (UK):22mg/L, Belnina (IT):23.1mg/L, Whistler (CA):24mg/L, Mont Roucous (FR):25mg/L, Ice Field (CA):27.5mg/L, Speyside Glenlivet (UK): 37mg/L, Crystal Gaysel (US):38mg/L, Cabreiroa (ES):50mg/L, Volvic (FR):60mg/L, Hawaiian spring water (US):91mg/L, Tinanto (UK):102mg/L, Fiji (FJ):105mg/L

Residual odors from tap water
Green tea’s flavor can be spoiled by odors emitted by anti-microbial agents and chalk present in tap water, as well as by microscopic plankton in water drawn from rivers. These must be appropriately eliminated by boiling or with water purifiers.

※ Improve the water quality by using a water filter for potable tap water
※ An activated carbon water filter can help reduce calcium and residual odors from antimicrobial agents.
Example: BRITA
※ Within a short period (3 to 5 minutes), its filtering can eliminate odors from sodium and similar sources.

※ When water is boiled, water clusters diminish in size, promoting tea infusion.
※ Oxygen and carbon dioxide exit water that was boiled and then allowed to cool, so the water should be topped up or changed to fresher water when it is to be used for tea products such as Sencha that have cool freshness.

Sencha:　Boost the tea’s refreshing qualities by using hot water that contains oxygen and carbon dioxide
Matcha:　Bring out the aroma and flavor by using water just before it boils
Bancha:　Bitterness and astringency can be reduced by using boiled water from which oxygen and carbon dioxide have escaped

Brewing method 1:　The relationship of temperature and taste component infusion

Roughly divided, green tea’s flavor consists of four taste elements: umami, sweet, astringent, and bitter. The hot water’s temperature can markedly change the amounts of the taste elements extracted from the tea. The astringent element, catechins, and the bitter element, caffeine, are extracted in greater amounts by water at higher temperature. In contrast, their extraction at lower temperatures is more difficult, and one portion of the catechins is barely extracted at all.

The extraction targets, umami components consisting of amino acids, are readily extracted not only at high temperatures but at low temperatures as well. Similarly, the longer the extraction time, the more is extracted.

Speaking generally, when brewing green tea, lower temperatures tend to bring out more umami, while higher temperatures make for stronger astringency and bitterness. In addition, the temperature of the hot water can change not just taste components but aroma as well. Hotter water tends to bring out a stronger aroma.。

The relationship of temperature and taste component infusion

The higher the quality of the tea leaves, the larger amounts of amino acids and catechins they tend to contain. For this reason, extraction at higher temperatures will cause the amino acids and catechins to cancel each other out, and will harm the high-quality tea’s especially concentrated umami. Therefore, it should be brewed at lower temperatures.

Brewing method 2:　Brewing to taste

One of tea’s special characteristics that is absent from other drinks is the ability of a single tea product to transform to different flavors depending on differences in the brewing method. Even with Sencha, the most widely consumed of Japanese teas, the better the quality, the more effective is the infusion. This means that enough taste components can be extracted at a minimum two or three times from the same tea leaves. And according to each step as the tea leaves gradually open during the first infusion, then the second infusion, one can enjoy varied tastes from a single batch of infused tea leaves by changing the water temperature and the brewing time.

The following figure gives an example of tasting three different types of flavors when brewing high-quality Sencha.

The first brew brings out the umami with a low temperature
The second brew is at a slightly higher temperature and has a light umami and bitterness.
Third brew is at a high temperature, for aroma and to taste refreshing astringency and bitterness.

With one batch of tea leaves, three types of tastes can be savored. This is the biggest difference from fermented black tea.

Brewing method 3:　Brewing suitable to each tea product

Taste components within the tea leaves vary depending upon the tea type and quality. For this reason, the brewing details must be adjusted to suit the various tea products. When doing so, the key is to balance three elements: temperature, infusion time, and amount of water.

Generally, if the tea leaves are of high quality, they tend to do best with little water, low temperature, and a long infusion time. When tea pottery such as small tea pots and tea bowls are used with high-quality tea, their small size is well matched to the small amount of water needed to infuse these teas.

※The taste of green tea is different depending on the product and grade.
After finding your favorite tea, find its best taste by learning the brewing method.