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Water and Tea, Part II

September 11, 2017 3 Comments

Following on from the previous article, let’s continue talking about the extremely large and complicated topic that is water and tea brewing.


After all, water is important for the taste of your tea. And the most effective thing you can do to improve your tea, short of getting better tea, is to improve your water.


What water is right for making tea?

Firstly, the results of a simple experiment.

look around you

I made several batches of water from scratch by adding magnesium sulfate (epsom salts) and sodium bicarbonate (bicarbonate/baking soda) to distilled water. I made two concentrates in separate bottles, and then titrated these concentrates into distilled water with the equation of 1000g DI water - weight in grams of concentrates added. The concentrates are made such that 1g of concentrate = 1mg/L of either the magnesium or bicarbonates. I will detail exactly how to make your own water at the end of this post.

I then tested brewing tea with each batch, with the goal of graphing the small changes in buffer and hardness against changes in taste. The same tea, ratio, teaware, brewing times, and temperature was used throughout. The only changed variable was the amount of buffer and magnesium in the water itself. The kettle was thoroughly rinsed with distilled before the new water was added to minimise mixing of different waters.


The tea was assessed informally for sweetness, body, and presence of any off flavours. At this time I don’t have the resources to do a better quality experiment, but I plan to do one in the future, using around 8 different kettles and sets of brewing tea, and tasting them side by side, blind with multiple participants. Stay tuned!

However, this experiment still proved interesting. It added evidence to some previously held theorising, and made me re-appreciate just how complex water chemistry is.

It is impossible to draw definitive conclusions, especially considering some very big caveats:

  • I only used magnesium, where some waters may also have calcium contributing to hardness. The reason for this is that it is a pain to get easily available sources of calcium to dissolve in water. I couldn't find solid literature talking about the direct effects of magnesium and calcium in tea brewing water. (If you have any relevant studies, please send them through!) But it is worth considering as many tap, bottled, and spring waters may have calcium as well as magnesium, in varying amounts.
  • Apart from this, there is a tonne of other things in water that may have varying levels of effects on the taste of brewed tea: for example sulphates, chlorides, silicates, potassium, pH etc. It becomes a lot more difficult to try and test for all the effects of these things without a proper lab, a science degree, and a bunch of time. Again, the main point of this experimentation was to see if there was a clear effect on the taste of brewed tea when varying the amounts of magnesium and bicarbonates.
  • But I think this experiment is definitely worthwhile to try at home, as it will really clearly demonstrate the vast range of flavour expression from the same tea with different water. Depending on your tap water, you could likely make better water from scratch using this system, and you could definitely make Reverse Osmosis water better this way.

some of the things in this weird clear stuff


The most obvious general trend I noticed was that the body or thickness of the tea increase in correlation with increasing HCO3 concentration, more so than magnesium concentration.
Sweetness followed a bell curve, with very little or none using distilled water, followed by a rise along with magnesium and HCO3 concentration, up to a point where it declined and vanished entirely with too many minerals.

Astringency seemed to go up the most with increased MG+ concentration, and slightly with increased HCO3 concentration.

Water that was too ‘hard’ had distinctly metallic, sour, harsh after tastes and mouthfeel.
Water that was too ‘soft’ lacked body, flavour, and sweetness.

The colour of the brewed tea liquor became progressively darker with increasing hardness.

    tea brewed for the same time with distilled (left) and hard water (right)

    In the sweet spot, there was a balance of the thickness of the infusion, no faulty aftertastes, proper expression of astringency and bitterness, and most noticeably, the best amount of sweetness (including huigan).

    On the graph, there is two zones. The light red is an approximation of a range where you should get maximum sweetness and a clean tea with good clarity of flavours. The dark red zone is where there is more body, and a little less sweetness depending on the tea, but there is no negative flavours from the water.



    Taken straight from Barista Hustle, here's how to make your own water.



    Baking Soda - NaHCO3, Sodium Bicarbonate, Bicarb (not baking powder)

    Epsom Salts - MgSO4, Magnesium Sulfate, Epsom Salts

    Deionised/Distilled/Ultra-pure water 

    You should be able to buy these ingredients at the supermarket for little cost.


    Scales (accurate to 0.01g)

    3 x ~1L water containers (preferably glass, and odour/residue free)


    • Dissolve 1.38g baking soda in 1L of deionised water — this is your “buffer” concentrate, or “alkalinity”. Label and set aside.
    • Dissolve 10.14g Epsom salts in another 1L of deionised water — this is your “Magnesium” concentrate, or “total hardness”. Label and set aside.

    Now that we have the two concentrates, we can start building our own water from distilled.

    From my earlier experimentation, this seems to be a good starting point for most teas, and will give a clean, clear, tea with good expression of flavours and sweetness, but not too much body.

    7g Buffer
    2.8g Mg
    990.2g Distilled water

    For heavier teas or if you prefer a bit more body/punch at the cost of some sweetness and crispness, we nearly double the previous recipe:

    12g Buffer
    5g Mg
    983g Distilled water

    The table below shows all the waters I tested and the amounts of buffer and magnesium for each.

    It seems like a small difference in terms of mg/L, but it makes a noticeable difference. Of course, again, caveat: these are based of my simple, very non-scientific experimentation, and are based on my particular tastes and biases and the tea I used. Your preference might be vastly different, so experiment heavily and find out!

    Represented as a (very) rough compass of flavours vs concentration of each:

    The beauty of making your own water this way, is that you can directly control the flavours, and that you can be almost perfectly consistent. Even buying spring water from some companies or especially locally can vary significantly depending on rainfall and other factors, between batches.

    Other advantages are that this water is cheap to make relative to buying spring water. Making the salt and buffer solutions is quite easy and cheap, and making a 1L batch of each will last a long time for making tea water.




    Again, my greater point with these two articles is to stress the importance of water on the taste of your brewed tea. At the very least I would strongly encourage you to try different waters that are available to you for brewing tea; don’t just assume that the water you currently use is the best water. If you’ve used it for a while, you will have adjusted to the flavours and they will be what you think of as ‘good’. But if you try out some different waters, you might find a whole bunch of flavours you didn’t think were possible before. If your tea tastes better, then you’ve just found the easiest thing you can do to improve your sessions! Fantastic!

    Play around with different water recipes to see what works for you, and just as importantly, what doesn’t. I think it’s a good idea to see the total range of water does and doesn’t do to the taste of your tea. This may help you in situations where you have unfamiliar water, or when brewing tea and it doesn’t quite taste as it should, or when assessing tea brewed by someone else or in an unfamiliar place. A tea that tastes bad in a shop might actually be a great tea underneath that subpar water. If you familiarise yourself with the general tastes associated with extremes of water, you’ll be better prepared for these situations.

    Water chemistry is decidedly more complex than the DIY method here can hope to COMPLETELY explore, but for practical purposes I think this is a great way to get started. If was a scientist and had access to mass spectroscopy and chromatography and other such methods, it would be interesting to see this experiment with water make up repeated and related directly to total extraction of tea compounds.

    Heavily drawing upon the book Water for Coffee, as well as the DIY water recipe approach from Barista Hustle.


    Have a play around yourself and see how you go.

    Enjoy your tea!

    3 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.


    November 16, 2017

    From FreshCup mag (Jan., 2017):
    Water wizard David Beeman, of GC Water, recommends water with a TDS measurement between 50–150 ppm, or 3–9 grains. Beeman has formulated water for hundreds of businesses large and small and crafted water guidelines for the Tea Association of the USA. He cites 150 ppm as the ideal amount of TDS in water for tea, provided the water is run through a reverse osmosis system, which filters the water completely, then reintroduces a mixture of calcium, potassium, and sodium to meet the suggested TDS measurements. Unlike coffee, NO MAGNESIUM is added, as it makes tea taste over-extracted and metallic in flavor.


    October 04, 2017

    Before I embark on this DIY water journey, just wondering what is the cheapest & most practical source of deionised/distilled water? (I’m in Sydney)

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