Wednesday, 22 August 2012

Water, and the lesson learned

Water is an often discussed topic among the tea drinkers and every one who takes the tea drinking a bit seriously faces this issue sooner or later. I think it is important to find a good water (source) which suits for tea. 

I wanted to write about this issue for a while and some recent experiences made me to do so. In Italy I was quite lucky since I found a good bottled water named Guiza Alpe, with TDS around 100mg/L and with slightly basic pH. The water had a sweetish taste itself and suited well for most of the teas I drink, moreover the price was excellent, around 1 euro for 12 litters (6x2L). 

The situation back home was a bit more complicated. I struggled to find a good water for quite some time. The tap water is very hard and heavily chlorinated here, so I looked up what kind of bottled water are available. Most of them had higher mineral content and I was also discouraged by the relatively high prices (what is interesting since our country is rich on natural mineral waters). So I went for filtered water. I bought a simple brita pitcher with filters, what helped to reduce the lime from the tap water but the filter had to be changed every to week. The frequent filter change made me think and I figured out how to overcome this problem. First I boiled the tap water in a kettle, then let it to cool down.

During the cooling the limestone precipitates what can be filtered off using a Brita pitcher with a filter cartridge which is not active anymore, so the filtering is only mechanical not chemical, thus the cartridge doesn't have to be changed. After this step the water is still not very good for tea due to the salty taste what comes from the decomposition of chlorine. The "chlorine" used for disinfection is sodium perchlorate which decomposes to oxygen (O2) and sodium chloride (NaCl, kitchen salt). Therefore, the water after the first filtration was filtered again using a second pitcher but this time with an active cartridge. The resulting water was soft. But softness itself is not enough to get good tea.
I was developing this system of getting the right water every now and then when I came home for a couple of days but after I returned 3 weeks ago and I have had more time to test this water, I realised that something is not right with it. I was re-tasting shengs from my collection and many of them which I remember as excellent tasted strange. In general they missed the thickness and the taste was often sour, especially in the case of younger shengs, though for Japanese greens and lighter oolongs it worked relatively good.

There is one important thing about filters, namely that the result is not constant. Activated carbon need some time until the filtering power reaches its maximum. Then, after each filtration, the efficiency drops resulting in different water, and at the end, in tea with different taste. It is also not the same if the water is filtered right before it goes to the kettle or if it's left in the pitcher for a couple of hours during which the activated carbon has more time to absorb the minerals. And lets face it, going through the procedure I described in order to get the right water is ridiculous, especially if the results is not as good as it should be. So there left nothing else just buy some bottled water in the local supermarket and test them. I found one with lower mineral content (148mg/L) but the tea with this water wasn't good, it had a metallic taste plus a sour-acidic finish. So I started to add another water with higher mineral content (388mg/l, water meant for babies). At the ratio softer / hared = 1/2 the taste was surprisingly good. Another interesting thing is how the water influences the colour of the brew. I was steeping the same tea with softer and harder water and the colours were quite different (harder water results in darker brew).
1) The water used for the tea preparation is more important than I thought.
2) Soft water doesn't always gives better tea. If the water is too soft the tea becomes sour-acidic and flat, on the other hand, if the water is too hard the tea may be fuller but its character and taste is suppressed by the soapy-salty taste of minerals (that's especially true for fragrant teas). 
3) When there is scale developing in the kettle it doesn't necessarily mean that the water is bad.
4) The hardness of the water has a significant effect on the colour of the brew, therefore comparing the colours of certain teas makes sense only when the brewing parameters, including the water, are the same or similar. 
5) For shengs the mineral content around 300mg/L seems to work well. Basic pH (above 7) gives better result and also helps to buffer (or neutralise) the potential acidity of the tea.

Finally one important note. A couple of months ago MarshalN wrote on teachat that he uses harder water for darker, heavier teas. Tim wrote the same and I was surprised and also sceptical that such water can work. Now I know how right they are.


  1. Hi! Thanks for such an informed article - it seems you have put a lot of effort into these experiments :)

    You're also right that soft water is not necessarily the best. That's why I use Brita only seldom - the softening effect harms some puerh.

    Does it not help to just let the water in a bowl or something overnight? It usually works well for me, most of the nasty smells gets out.

    Also, prolonged boiling helps, but it damages the water in a different way, so it's not the best option I guess.

    I'd say that the purifying powers of Chaozhou kettle&tea stove should handle even quite bad water. But these sets are hard to get I guess.

  2. Hi Jakub

    I was a couple of months ago in Prague and my impression was that the tap water is pretty good there, so leave it to air out that little chlorine smell is probably enough.
    The situation in my town is quite different. We are surrounded by hills and mountains made of limestone (actually there is plenty of limestone mines around), so the tap water which comes from the local source is very hard and moreover there is a fair amount of chlorine added to it. It is difficult to turn such water into a good tea water. The extensive filtration removes the majority of lime but also all other minerals are gone and the result is a kind of distilled water with a bit of limestone. Though brita states that their filters doesn’t remove minerals such as magnesium or iron but I can not imagine such selective filtration using activated carbon.
    Good to know about the Chaozhou thing since I am planning to invest in a proper kettle in the future.
    All the best

  3. Regarding tea colour, I did some tests many moons ago with two vastly different water. The results are pretty striking

  4. Interesting post, MarshalN!
    I was testing the two different waters with a 2012 sheng and the difference in colors were significant too. I should have done some pics.
    Actually when I was re-testing my cakes I started to worry if they age at all since the colors of the brews were brighter as I expected. As soon as I changed the water, the outcome was different different.

  5. Hi NorberT,

    Thanks for sharing that, good water is most important indeed.

    I'm curious to know more about the kettle in your last picture - is that a clay kettle? Where is it from?

    - Martin