When you drink the water, remember the spring (proverb)

Tea is ~99% water so there is no doubt that the quality of that water will make a difference to the flavours of the cup.
Tap water here is very “hard” so it leaves limescale on teapots and kettles and doesn’t taste great. Buying water is a complicated business though. Bottled Water is so heavily marketed it is difficult to disregard the branding and get a true comparison of the products. Here is a breakdown of the main types of water that are found here in Ireland:

  • Public mains water – goes through a set of treatment process before it is distributed to ensure that it is filtered and sterilised and fit for drinking. The main stages in water treatment are screening, flocculation, sedimentation (clarification), filtration, chlorination, fluoridation and pH adjustment. Chlorine is added to kill bacteria and afterwards ammonia is sometimes added to the water to reduce the taste left by the chlorine. Fluoride is also added to prevent tooth decay.
  • Filtered water – Filtering tap water with a simple jug filters will remove visible solids and most of the chlorine. They will improve the taste but it will not remove fluoride or change the mineral content significantly and so it will not soften the water.
  • Purified/distilled water –Water that has been produced by a process such as distillation, deionization, reverse osmosis or other process. It will have no minerals.
  • Spring water – Comes from underground source but naturally flows on the earth’s surface. It is naturally filtrated by passing through layers of rocks and soil. Spring water may be treated by ozonation, UV light and chlorination and unlike mineral water does not need to have a stable composition.
  • Natural mineral water – Natural mineral water come from natural mineral water springs and contains at least 240 parts per million Total Dissolved Solids (TDS). Natural mineral waters are pure at source and are distinguished from other types of bottled water by its constant level of minerals. It originates from a protected underground water source. No minerals or chemical preservatives may be added to the water.

Tasting water and matching it with food is a whole other world (see Bottled Water of the World). There is a range of factors that are considered in the taste of water but the mineral composition and the acidity level (pH) are two of the main factors for still water. Acidic waters have a pH of less than 7 and alkaline water have a pH greater than 7. Alkaline water tends to taste sweeter and softer than neutral or acidic water. The Total Dissolved Solids (TDS) is the sum total of all the mineral in the water (most commonly Calcium, Magnesium, Sodium and Potassium). These minerals give water a heaviness and it correlates with the hardness of the water.
Below is an interesting graph of pH and TDS plotted for the main water brands (source).

Mineral Water Comparison (Source)

Mineral Water Comparison (Source)

For tea making, we are looking for water that is not too mineralised and doesn’t have any dominant mineral that stands out. Distilled water (that has no minerals) is not good either because it is too flat. Ideally tea water would be neutral pH 6-8, have no chlorine and have total dissolved solids (TDS) of ~100ppm.

Still confused about what’s what with water? Interestingly, there are some good explanations in Bret Easton Ellis’s book “American Psycho” (excerpt here)!

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7 Responses to When you drink the water, remember the spring (proverb)

  1. The O'Dore says:


    Very interesting post. Could you develop this a little further and suggest what types of water are compatible with what types of tea? And possibly ways of mitigating this, e.g., possible increase / decrease of water temperature and / or steeping time depending on tea/water combination. Okay, a rather multi-dimensional problem, but I would rather *you* run this type of experiments than me 😉

    Good luck,

    PS: American Psycho? Great cultural reference…

    • Breda says:

      HI Theo,
      Thank you for the comment. There isn’t a “type” of water that suits a particular tea. The water’s job is to allow the flavour of the tea to shine. Water that has lots of minerals will interfere with the taste. Distilled water has no minerals, which might seem ideal, but in practice makes the tea flat and uninteresting.
      This is why a neutral pH and a low (but not zero) mineral content are recommended for all teas. It allows the flavour of the tea to stand out. From my own experience I have found shou pu-ehr and darker oolongs to be more forgiving of my tap water than white or green tea.
      Varying the temperature will not compensate for water quality. Extending the steeping time will not work either and I’m afraid that over-steeped tea and poor quality water would not make a pleasant combination.
      Hope this helps,

      PS – if the truth be told I skipped huge chunks of the American Psycho book. I probably read less than half the book. That dialogue about the water stuck in my head though!!

  2. The O’Dore: such an experiment is on my Bucket List. When I have access to a lab equipped with a spectrophotometer, I’ll do a strictly-controlled tea-brewing experiment and put the results online for all to see 🙂

    Breda: I absolutely agree. Water for drinking should be higher in mineral content than water for brewing tea. The chart in your post shows water that’s best for drinking. For tea, however, the Chinese tend to use Nongfu Spring (the red logo just under the word ‘good’) because of its neutral pH and low mineral content.

  3. I’m skeptical of recommendations to use or give preference to bottled water except in the few cases where the tap water really tastes outright terrible or completely unusable for satisfactorily brewing tea.

    Bottled water is incredibly costly from an environmental standpoint–much more so than the impacts associated with traditionally-processed loose tea. Tea is lightweight so shipping costs are negligible, whereas packing and shipping water is more expensive because it is so much heavier.

    I’ve lived in several parts of the U.S., including a few (Delaware and San Diego) where the tap water didn’t taste great. But I still brewed my tea with tap water. If that excludes me from the ranks of tea connoisseurs, then frankly I don’t care. I’ve done taste tests with different types of water, and I do sometimes notice a difference, especially in the cases of individual regions that have particularly bad water. Sylvia, one of the other RateTea admins, lives in a suburb of Philadelphia and I really dislike the water at her house. But after doing some controlled experiment, comparing our two tap waters, I found that the difference is subtle at best, much less than factors like brewing temperature, or the vessel used to steep the tea in, and I also found that there are ways I can work with the water at her house to get tea that I still enjoy.

    I love exploring the nuances of flavor and aroma in the more subtle teas, but I question whether it is socially responsible or even ethical for us to be using a very costly resource like bottled water for purely aesthetic reasons. I personally would only drink bottled water in the case that the water was either outright unsafe, or tasted so terrible that I couldn’t bear to drink it. Otherwise, I’d just get used to it and adjust my brewing and tea drinking experience around what I think is the most environmentally-responsible decision. Also, bottled water is just so darned expensive, and I brew so much tea, that it takes away money I could be spending on getting better-quality tea, and I think, with my decent-tasting city tap water, the better tea makes much more of a difference than the water would.

    Using a filter on the other hand, is not as costly, and I’ve sometimes filtered my water. I find it is only really noticeable with the more subtle teas though. I like a lot of bold-flavored teas where I don’t even notice a difference.

    • Breda says:

      Thanks for the comment Alex. The aim of the post was to provide clarity about all the different types of water that are out there. While there is an ideal water type for brewing tea, I was not suggesting that all tea would only be made with bottled water. Sometimes the information can lead to interesting discoveries. So for instance, I have since found out that the water from my parent’s well has a low mineral content and a neutral pH. Guess who’s stocking up on water when I make the trip over? ;-).
      The cost of bottled water (environmentally and economically) was outside the scope of this article but it is something that I will consider writing about in the future.

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