Tea lovers have long known that the quality of the water used to brew tea can have a profound impact on the taste of the final beverage. In ancient China, tea masters traveled great distances to find the best water for tea. Some of the most famous water sources in the country became known for their unique mineral content and flavor.
A famous Chinese proverb says, "Water is the mother of tea." It shows how important water is to the quality of tea. If you want to make the best cup of tea, it is important to use the proper water.
In this blogpost, we will discuss how water affects tea's aroma, taste, and mouthfeel. We will also provide tips on choosing the best water for your next cup of tea.
The best water for tea: ancients' perspective
As early as the 8th century, the "Tea Sage" Lu Yu wrote about the importance of water quality in his book The Classic of Tea. He believed that the best water for tea was "spring water that flowed slowly over stone pools". He also said that the water should be soft and slightly sweet, with a clear and delicate taste.
One story about Lu Yu says that he could tell when his lazy disciple drew water from the bank of a famed river instead of walking over the bridge and dropping the bucket into the stream to draw the purest water. This story shows the importance that tea lovers placed on water quality more than 1000 years ago.
Lu Yu went into further detail by classifying all then-existing water sources according to their water quality. In chapter 5 of his book on tea, we read: "其水, 用山水上, 江水中, 井水下". It translates to: "For water, mountain water is the best, river water the second, and water from wells is the least suitable." As someone, who has traveled far and wide across the empire, he goes as far as pointing to a specific spring in Mount Ming in Sichuan as producing the best water for tea overall.
Lu Yu's classification remains popular today in tea circles. More than 1000 years ago, he could grasp how water changes according to its origin. He also noticed the influence it had on the tea brew. Under the same conditions (tea leaves, teaware), simply altering the water will make the brew different. Today, armed with the help of science, let's explore how it happens from a modern perspective.
How water impacts tea soup
There is a variety of physical and chemical properties of water that have an impact on tea brewing. Let's take a look at the most essential ones.
Hard or soft water for tea
As we know from the times of Lu Yu, soft water is reputedly most suitable for making tea. We define the hardness or softness of the water by measuring the overall amount of calcium and magnesium (usually in mg per L). The standard requirement for soft water per the US National Tea Association is 8 ppm (or 8mg per 1l). That coincides with the State standard Chinese requirement.
Hard water can make tea taste flat and astringent. That is because the calcium in hard water binds to some of the tea's essential compounds responsible for its taste and aroma. It prevents the compounds from properly infusing into the water, resulting in a less flavorful cup of tea.
Hard water can also make tea look cloudy and unappealing. When using hard water, one can notice a thin film floating on the surface of the tea. It is sometimes referred to as "tea scum". Additionally, a cloudy solid sometimes forms when the tea has cooled down. It is known as "tea cream".
Softer water, on the other hand, produces a clearer, bright-colored cup of tea without any residues.
Interestingly, tea taste due to the water hardness can produce different "liking" results. Research conducted among a number of panelists compared green and black tea using water with three different hardness levels: bottled spring water (soft), tap (hard), and deionized (softest). Most panelists appreciated the black tea made with the spring water as the most visually appealing and sweetest. However, for green tea, there was a clearly expressed preference for tap water-made tea.
It seems that softer water could extract more of the catechins in tea leaves. As a type of antioxidant, catechins also contribute to the overall bitterness in taste. Thus, the green tea brewed with soft water had a more pronounced (and bitter) taste, which the panelists did not like.
pH of water
The overall requirements vary between 6 – 8 pH. 6 is slightly acidic on this scale, while 8 is slightly alkaline. Research shows that the best results are achieved with water between 6 and 7pH. The improvement is mostly in flavor and clarity: using water within this pH range results in a more tangible taste and aroma, as well as a lack of turbidity or cloudiness in the tea liquor. Going below 6 or above 7 leads to decreased flavor and increased turbidity. There are suggestions that pH impacts the infusion capacity of the water, thus leading to a decreased amount of taste and aroma-related compounds (mostly catechins) released in the tea brew.
As early as the Tang dynasty, Lu Yu believed that adding salt to water during the first boil would help neutralize any flavors or aromas present in the water and allow the tea flavor to shine through. We might see that as the first attempt to control the water in order to achieve the best taste and aroma for the tea.
While the water's mineral content clearly affects the brew's appearance and flavor, there is no single "best" water for tea.
Different teas benefit from different waters and personal taste also plays a role. Existing practice is to add certain rocks to the water kettle. They presumably help mineralize the water or lend it a particular character. Some enthusiasts go to the extent of fabricating their own water with strictly controlled mineral content and ratio to achieve the desired outcome in their teacups.
Choosing the right water for a particular tea is part of the art of brewing and something that comes with long experience. There is no one correct answer. The best way to find suitable water for you is to experiment and see what you enjoy.
While thinking about more complicated factors, such as mineral content and pH, let's not forget a simple fact: the quantity of water directly impacts your tea taste. Namely, increasing the amount of water will provide a lighter infusion, less caffeine, and a more subtle overall taste. Alternatively, cutting down on water will result in a bolder, more intensive brew with a bigger caffeine load and clearly expressed taste.
Is tap water good for tea?
That would vary according to the area of living, local water hygiene standards, and personal taste. As mentioned earlier, in research, some panelists clearly favored using tap water for tea over bottled or deionized water. That might be related to their previous experience, based on the type of tea they usually had, or grew up with. It also might be because of cultural differences, where a certain type of tea is supposed to taste in a certain way.
The main thing to consider for tap water is its purity. Tap water may contain unwanted additives like heavy metals, chlorine, and fluoride. All of them have a direct impact on tea. In fact, they can destroy most of the flavor and aroma in there. There are a few things you can do to ensure your water is suitable for making tea:
How to ensure the best water for tea
- Boiling water is the simplest and most effective way to purify it. It will kill most bacteria and viruses and also remove any chlorine that may be present.
- Use a water filter. It will remove impurities and improve the taste. Different types of water filters are available, so you can choose one that's right for your needs. Some filters remove specific contaminants, such as chlorine or fluoride. Others improve the overall taste of the water.
- Use bottled water; bottled water is purified and does not contain any contaminants that can affect the taste of tea. (But keep in mind that using bottled water is not environmentally friendly.)
- Let the water stay for a while (or simply overnight) before using it to brew tea. That will give the chlorine time to evaporate.
- Avoid using water that has been boiled more than once. It can make the water taste flat.
- If you use bottled water, choose a brand specifically designed for tea. These brands often have a lower pH and less minerals than regular bottled water.
Bonus advice: Cold brew your tea. That is a great way to reduce the mineral taste of tea and avoid the cloudiness that hard water can bring to your cup. Cold-brewing your tea also enhances the umami (savory) taste and mutes bitter notes.
With a bit of experimentation, you'll be able to find the perfect water for your tea. Enjoy!