Why Does the Same Tea Taste So Different in Purified Water vs. Tap Water?
A Blog About Brewing Water and Tea Soup Flavor
The same tea can taste so different when brewed with purified water versus tap water? Why is it that even with mineral water, teas brewed with different regions and brands end up with completely different tea soup styles? Let me take you through the fundamental relationship between brewing water and tea soup flavor.
In a previous blog, I explained that tea leaves themselves are like a sponge. Different flavors are themselves composed of different proportions of large-, medium-, and small-molecule compounds. Therefore, the essence of how different brewing waters change tea soup flavor is that different waters can change the release rate of the large-, medium-, and small-molecule compounds in the tea.
Light-Aroma Rock Tea: When Rich Mineral Water Gets in the Way
Let’s start with light-aroma rock tea. In terms of processing, the goal is to retain as many amino acids and aroma compounds as possible, but at the same time, some stimulating substances such as polyphenols are also retained.
If you choose water with an extremely rich mineral content, the tea soup will come out very clear, and you’ll feel that its aroma simply cannot emerge. The core reason is that mineral water contains many unstable ions, which adsorb onto some of the tea’s internal compounds during brewing.
The reason people think the tea soup is bitter and astringent and the aroma is not apparent under these conditions is also because the ions in this type of water bind more selectively with certain tea compounds. For example, if most of what they bind is small-molecule substances, then small-molecule substances are released with greater difficulty, while the release of medium- and large-molecule substances is not affected much. The final result is that the overall flavor of the tea soup is unbalanced, aroma compounds are lost, and the tea soup seems very bitter and astringent.
Soft Water Can Bring Balance
If you want this kind of tea soup, which is itself rich in medium-molecule compounds, to be more balanced and pleasant to drink, you only need to choose a soft water that can inhibit the release of medium molecules. This is equivalent to artificially weakening the bitter, astringent substances in the middle range, thereby achieving balance between aroma and taste.
High-Mineral Water Can Be Ideal for Dark Tea and Ripe Pu’er
But if you use water with a very high mineral content to brew dark tea or ripe Pu’er that already has a high degree of fermentation and oxidation, it can instead make the tea soup especially mellow. The principle is actually the same. The vast majority of the internal compounds in dark tea exist in the form of large molecules.
Because during fermentation or storage, large molecules gradually break down and then repolymerize with small-molecule substances into more stable compounds. Therefore, water with a high mineral content can instead cooperate with these large-molecule substances. These abundant ions in the tea soup better support the thickness of the tea soup, somewhat like a skeleton, forming a fuller, softer tea soup texture.
Choosing Water Is Like Modifying Flavor
I believe the essence of choosing water is similar to changing brewing technique: both are artificial modifications of flavor.
The ions in different waters also selectively capture certain internal compounds in the tea soup. This is, to some extent, targeted extraction, and it can adjust the flavor of the tea soup. Brewing technique itself is also a way of assembling flavor through manipulation, allowing you to more freely configure the release ratio of large-, medium-, and small-molecule compounds.
But for most people, changing the water may be much easier than learning brewing technique. This is also why I find it hard to understand the view in traditional tea circles that “good tea tastes good no matter how you brew it,” because they are also a group of people who are very particular about how to choose brewing water. But if the tea itself tastes good, why still use different waters to selectively modify it?
A Simple Way to Think About It: Water Is the Hot Pot Base
Finally, let me share with you how ordinary tea drinkers should choose the water that suits them best. I’ve summed up a very interesting rule: water can be understood as the hot pot base, while tea leaves are the ingredients to be cooked.
For example, for teas with a high degree of freshness such as some green teas and white teas, choosing a heavy beef tallow hot pot base is obviously very unsuitable. Instead, they are very well suited to purified water or soft water, so that the flavor of the ingredients themselves can be preserved to the greatest extent.
Not All Spring Water Is Good for Tea
I’d also like to mention one point: not all spring water is suitable for brewing tea. Because of differences in environment from region to region, the proportions of internal compounds in spring water are actually different. If the water itself has a very high TDS value, brewing green tea with it will instead have the opposite effect.
For Dancong and Rock Tea: Slightly Mineral Water Can Help
Also, when brewing some of the more common Dancong and rock teas on the market with medium roast and medium oxidation, under perfect conditions they are actually suitable for brewing with water that has a certain amount of mineral content. Because the processing of oolong tea brings a certain degree of transformation to the tea’s internal compounds, and they also need some minerals to serve as a skeleton to support the dimensionality of the overall tea soup flavor.
This is also why many people who brew Dancong and rock tea use Wuyishan brewing water. This type of water has a relatively neutral mineral content; it will not excessively compete for and occupy the release of aroma compounds in these two types of tea, while also providing a certain amount of minerals to support the overall tea soup skeleton, making the overall flavor more balanced.
For High-Fermentation, High-Oxidation, High-Roast Teas
Finally, there are teas with high fermentation, high oxidation, and high roast levels. They are actually similar to meat that has been repeatedly cured, and using a rich, spicy and numbing broth is actually best.
Common examples include some dark teas, Pu’er teas, and some full-roast rock teas. What they pursue is not aroma, but a thicker, more textured tea soup experience. At this time, using water with a high mineral content can produce a one-plus-one-is-greater-than-two flavor effect.
My Recommendation: Purified Water
Whether I’m testing or making basic recommendations to users, I still tend to recommend purified water more. During processing, purified water removes as many minerals as possible. It has stronger stability, and its quality is less likely to change because of different production regions. In addition, purified water modifies tea the least. Under the same brewing technique, it can preserve the tea soup’s original flavor and processing state as objectively as possible.
Most mineral water is essentially putting a beauty filter on the tea. Although it filters out some things you consider bad, at the same time it may also cover up the tea’s problems or some of its flavor possibilities.
If you have any questions about tea brewing and processing, you’re welcome to leave us a message.
written by siyutao art team
