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Water and Tea, Part I

August 04, 2017 4 Comments

“I hate how every tea blog article about water starts with a quote from me” -Chinese scholar Lu Yu, ca. 1652.

Let’s talk about water.Look around you. Water is everywhere. It’s powerful stuff, especially when combined with tea leaves.

The purpose of this article will be to:

  1. Investigate what we can practically do to improve tea via water
  2. Examine some common water related myths

There have been numerous discussions about water across Facebook, blogs, and forums. But we need to go deeper. Water isimportant. Aside from the quality of the tea itself, it is the number one biggest contributor to flavour. Extremes of water softness and hardness are well known; scale in your kettle from too much calcium, flat tasting tea from distilled water, and even scum on the surface of your tea (again, too much calcium).

But what about more subtle variations in the taste of tea, with water that isn’t extremely hard or soft? There’s a big range of flavours correlating to relatively small changes in water makeup.

Perhaps you have experienced this yourself; brewing up a familiar tea at a friend’s place, or away from home, only for it to taste not quite as good as it normally does. Put it down to a different day, or different equipment, or just a slightly different cross-section of leaves. But repeat the scenario with every other variable controlled - tea-ware, temperature, infusion timing, ratios, et cetera - but with two different waters, there will inevitably be a difference in taste.

always mindful of the fact I'm nerding over water for tea whilst billions of people don't have access to clean water.

Some basic water concepts:


    • Minerals, usually in the form of calcium or magnesium carbonates, contribute to the total hardness of water. Total hardness can be divided into temporary hardness, and permanent hardness.
      • Temporary hardness is hardness (calcium and magnesium bicarbonate) that will precipitate when boiled. Thus the hardness can be reduced slightly by boiling, or by chemical softening.
      • Permanent hardness is mineral content that cannot be removed by boiling, usually chlorides or sulphates
    • Water hardness is usually only an expression of some type of measurement of the above minerals. There is various different ways to measure and express hardness, and it can get confusing. These include PPM, German degrees, French degrees, and mg/L CaCO3,. Aside from the above minerals, there can be all kinds of things in the water; zinc, copper, manganese, iron, aluminum, silicates, bacteria, etc...whether these contributeas much to the flavour as the hardness minerals is unknown.

    • TheTDS (Total Dissolved Solids) of the water is a different thing to hardness. It measures all the dissolved inorganic solids in the water, whether or not they contribute to the temporary or permanent hardness. Thus for our purposes of investigating the effects of different waters on tea extraction, the most likely culprits being the hardness and pH, TDS is an inadequate measurement. Two waters can have the same TDS but be made up differently and thus perform differently

    • The mineral content determines the pH of the water, which is a measure of the acidity or alkalinity. pH has a potentially significant effect on the extraction of flavour compounds from the tea. pH that is too high perhaps leads toless being extracted from the tea.

    The hardness of the brewing water directly affect the flavour of brewed tea. This happens in two ways:

    • Chemical interaction during the brewing of the tea; i.e different minerals in the water affect what or how much of certain compounds from the tea leaf are extracted into the water.

    • The taste and mouth feel of the water by itself will carry over somewhat to the brewed tea. I.e if the water is thick and salty, the tea will likely be also.

    It seems pertinent to experiment with different waters for brewing tea. It is perhaps the one thing a drinker has the most control over in determining the final taste of their tea. A starting point would be to try tap water and various bottled waters, including distilled, to brew the same tea, in the same tea ware, side by side. Do this blind, and then again non-blind. Doing it blind will allow you to hopefully ignore some biases that would pop up if brewing openly, but may end up with you preferring the most familiar tasting water. Tasting it non-blind afterwards will allow you to more directly correlate the different waters with a change in taste.

    The more hardcore experimentation would be to make up various batches of water from distilled by adding salts, to correlate changes in taste directly to changes in temporary and total hardness. We plan to do just that in a future part of this transmission.

    Below is a table of various water sources along with their respective traits.


    PRO +

    CON -

    Tap (filtered, unfiltered)

    Cheapest, least resource intensive, most convenient.

    Inconsistent, potentially not tasty depending on specific source.

    Reverse Osmosis with re-mineralisation

    Potentially tastier than tap water.

    Expensive, resource intensive andincredibly wasteful, inconsistent, almost impossible to control theamountof each of the minerals you are adding back in.


    Usually consistent, fairly convenient, potentially tastier than tap.

    Expensive, resource/environmentally intensive.

    Local spring

    Potentially tastier than tap, less resource intensive and cheaper than buying bottled.

    Not too convenient, not possible for many people, inconsistent, still requires moderate resources in most situations (a car burning fuel, containers. The more you fill up on per trip the more efficient in terms of carbon).

    DIY (Distilled + salts, source water + salts)

    Cheapest after straight tap water, can be perfectly consistent, can control exact mineral content and adjust as needed = highest degree of accuracy for maximum tastiness.

    Slightly more time consuming than tap, need source of distilled water or tap water softer than what you are aiming for.

    Ultimately, the best water for your tea will depend on your taste preferences, best found out through trying a whole bunch of different waters, as well as how highly you rank taste over other factors like convenience and cost. When evaluating teas for purchase, consistency is the most important aspect; you want teas you are pitting against each other to have a level playing field.

    To close off part I, let’s look at some common tea and water related myths.


    Don’t use water that has been boiled more than once to brew tea/don’t reboil your kettle.

    This comes up fairly frequently on all kinds of tea websites (usually ones also trying to sell magic water enhancing beads), Facebook, and forums.
    Simply put,dissolved oxygen concentration in water at 100C is 0ppm.

    Once the water has been boiled, it is incredibly likely all the oxygen has boiled out of solution. So boiling it more than once will change nothing. As it cools, it will slowly re-absorb oxygen from the atmosphere.

    Boiling water will however do some other things to your water; as we discussed above, it could potentially reduce the temporary hardness, leading to a different mineral content. The likelihood of this being a significant reduction over the duration of a tea session is unlikely, but could explain the reason why tea boiled and then cooled tastes different to the same water not-previously boiled. The other, more likely reasons are that the dissolved carbon dioxide has boiled out, leaving you with a lower pH, bias, or that the kettle you used to boil the water imparted some ions to the water.

    Either way, there is nothing to be gained by discarding once boiled water. It is simply wasteful.


    Using charcoal instead of gas/induction/electricty to heat your water changes the taste of the water.

    Unless the kettle is porous enough to leak water (clay is porous, but not enough to let smoke in directly through it.), using charcoal to heat it will not affect the taste of the water directly. Indirectly, it will release a smell into the air, which will contribute to a perception of change in taste when drinking the tea. Different kettle materials, such as stainless steel, iron as in a tetsubin, or using a clay kettle, will change the taste water by imparting ions to it as it boils. Stainless, or perhaps glass, would potentially offer the most neutral taste with less available ions, whist an iron tetsubin and clay would contribute more.

    Potentially, if the lid was left off the kettle as it was heated over charcoal, some particles from the smoke/vapours could land inside the kettle and contribute slightly to its taste.

    In summary, the charcoal itself is unlikely to be directly changing the taste of the water. That is not to discredit the enjoyment of its smell or for some perhaps the ritualistic aspect of its use.


    Drinking distilled water is bad for you, drinking salts added to distilled water is even worse for you. Drinking super purified water is the best for you.

    It isgenerally not advised to drink large quantities of distilled/demineralised water over a long period of time, as it will decrease the amount of electrolytes and salts in the body. This could or could not be significant depending on the individual, as well as their diet. Generally it is advisable to drink water that contains some mineral content. In the case of making water from scratch using distilled water and adding salts, minerals are being added to the water. This is no different to drinking water that already has mineral content ‘naturally’. Some people are worried that adding salts will increase intake to dangerous levels; making water with magnesium or calcium ‘salts’ (bicarbonates) is not the same thing as eating more common salt (sodium chloride).



    That’s all for now. We will continue to explore water in more depth in part II of this series. All comments, criticisms, and discussions are encouraged. What has been your experience with water and tea?

    As always, remember to enjoy your tea.

    4 Responses


    December 04, 2017

    I have not “made” my own water blends but I have found certain spring waters that suit my taste best. I drink yerba mate and it seems more dificult to extract flavors from mate during the steeping process than it is from other teas. I find that a mineral rich water (especially magnesium and calcium) seem to provide a more darker flavorful result. Also yerba mate (like green tea) is a temperature sensitive tea so you can’t exceed 180 degrees F. This lower heat also makes extraction from steeping more problematic. I found a spring water brand at a local market in MN that made an extremely dark tea but was overly flat and off tasting, almost “swampy” in flavor. However if I blended that water with another less “swampy” brand of spring water it restored a pleasing flavor. This blend of mineral rich spring waters also increased the brewing life of the tea. Yerba mate is a tea that is intended to be brewed more than once. I could almost double the use of my loose leaf tea bags (3 or 4 times) and still extract a drinkable tea. Time to steep was also a factor I had to refine and consider. Circumstances dictated that I increase the steep time with each successive brew. This method combined with proper selection of water allowed me to effectively double the life of my loose leaf tea and cut in half my cost on yerba mate.

    Thank you for the article. It was enlightening and I hope you continue to share.

    Ryan Harlow
    Ryan Harlow

    August 07, 2017

    Wonderful post! I’ve been asking myself a lot of these questions for some time, and it’s great to finally see someone shedding some light on this.

    As someone that got introduced to this site via barista hustle how do you feel Matt Pergers water recipe would be for a jumping off point for brewing tea? I’ve just begun getting into the rabbit hole of blending my own water but I eagerly await having a recipe for tea!

    Again kudos for writing such an informative post. I’ll be greatly looking forward to future content that comes from ya’ll.

    Jeremiah Kef
    Jeremiah Kef

    August 05, 2017

    Finally. A forum for teas as well! I feel that it’s really way underrated and too many myths about it! Thanks for breaking things down!

    I had been seeking ways to improve the quality of teas- and realising without a good control and understanding of water to brew the teas, all the efforts are in vain and wasteful.

    Hopefully there will be more write up on what contributes to the taste and the optimal or good range of minerals and ppm for the brewing water for tea. Just as the BH have on the range for the brewing water for coffee!

    Looking forward! And excited for this new movement! Thanks for the setting this up!

    Dylan Conroy
    Dylan Conroy

    August 05, 2017

    I have done multiple small scale tastings with water, and I actually found that double osmosis water inhibits the taste of the tea.
    For this tasting, I used Huang Shan Mao Feng, a very light green tea. This tea was used because the subtly of this tea will be the most affected by the water, as opposed to let’s say a Gua Pian whose bold vegetal flavor will always be left intact no matter the water source.

    When tasted against Nestle Spring water, double osmosis water made the Mao Feng more bitter, making a first pluck Mao Feng taste like a mid spring. The man from the water store said that taste tests with coffee found the same thing.

    Before the tasting, he measured the PPM of both waters and found the double osmosis water to be around 0PPM and Nestle Pure life to be around 50. (It’s been a few years so these numbers could be very off, but the point is Nestle had more).
    The conclusion was that tea actually prefers water with stuff in it. This is in contrast with the common assumption that the purer the water, the better the tea.

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