Water may be a most taken for granted element in tea-making but is a crucial one. The amount and nature of its mineral contents, how it is heated, and, as some argue, its own molecular state are of vital contribution to the taste, colour, and texture of the final infusion.
ph value matters
People often talk about whether to use soft or hard water. I look at it in another way. I’d prefer a rather neutral pH water with very slight alkaline inclination (i.e. 7.5~8 approximately) such that there is the least influence on the tea while maintaining a pleasant taste. It has also to contain not a lot of total dissolved solids (TDS). Excessive minerals or dissolved compounds such as various metals, calcium, sulphates, and bicarbonates do react with tea substances to form things that may not be contributive to good tastes. Precipitations can form at one stage or another and the taste of the final infusion is often quite severely affected. Mineral water, therefore, is NOT a suitable choice.
Use low TDS water
For those who use bottled water, use a spring water rather than a mineral water. The former category generally has lower mineral content. Check the label and make sure the total mineral content listed is within the range of 120 mg per litre (just add up the numbers next to each item). Some teas fares alright with 150 mg per litre, but quality does vary.
Distilled water, if nothing else
Do not use distilled water, unless you have otherwise unsafe sources. More and more health professionals are understanding that habitual drinking of distilled water can cause health problems. It is not good to the taste of tea anyway.
An effective filter: the best and most economical choice
For my own daily use, I have a filtration system to my water inlet. It is a fine ceramic water filter system that basically gives me water that is good for drinking and tea-making. The water is sweet and low enough in mineral content that I have no need even to de-chalk my kettle (I do boil a lot of water daily).
I had the same filter installed in my tea bars with additional elements. A customer who used to ship in a fine (and very, very expensive) bottled spring water from Japan for his household use brought in his water for our test one day. We had a few blinded tasting sessions and the water ranked the best in taste amongst the crowd. It even won our filtered and treated tap water, but only marginally. However, when it came to using the water to make tea, our tap water was easily the champion.
The taste quality of the tap water in Hong Kong has degenerated much since I was a kid, although the related government agency has been doing an effective job in ensuring safety. I am sure if a user-point filtration set up can bring our tap water up to par with one of the most expensive bottled water from Japan, users in many other cities can do a much better job. There are enough people beginning to understand the need to further treat their own water supply that every now and then new and sometimes better products come up. One is never limited in choices of filter.
Some people recommend reverse osmosis filtration but I think the water is a little too pale coming out of it, almost like a distilled water, which I do not recommend. For the price of such systems, you may be able to find an ionizer with targetable pH output value.
Key to good filtration: maintenance
The filter really is a worthwhile investment if you think of how much water you use everyday and the quality guarantee this could bring to not only the tea taste, but also your household water supply for better health.
One crucial practice in the use of water filter is to manage changing and cleaning of your system regularly. An outdated filter can be a source of contamination itself. Do not take this simple procedure for granted and make effort to remind yourself to do it or have it done. I have seen some extremely prestigious hotel clients with highly disciplined managers overlooking this to have failed to find out why their water tasted bad.
For those who are extremely picky, there is also the water “re-energizing” systems that claim to break down congregated water molecules and re-align them, in attempts to re-instate the molecular patterns of virgin spring water. The taste is supposed to be sweeter and the texture more silky. There are a few brands around and some are rather expensive. Install this only if you are comfortable with the budget and can feel what it really does. This is good only as an additional filter to your basic system.
The water heating set up, on the other hand, is crucial.
Now the kettle
If you do not have a big family or if you make tea mostly in the Gongfu manner, a 1-litre, 2500 W electric kettle does the job real well. Go for a 1.5 litre, 3500 W (or higher) piece if your family is over six or seven people and you often use a giant teapot for them. Heating water quickly and evenly enough not only minimizes your wait, but is actually preserving the sweetness and texture of the water. Slow heating only drives away oxygen dissolved in the water and congregates molecules of the minerals, making your water taste rough. Therefore, always heat only the needed amount and do not re-boil water.
To choose a good kettle design, make sure the inside bottom of the kettle is flat and easy to clean, without those old-style tubular “heating elements” that would rust and hide calcified deposits. Or you may consider induction heating with which you may have a wider choice of kettle designs.
Another key feature is the balance between how the spout would pour and the handle would lift the filled kettle. I know this sounds awkward since you can’t possibly try filling water in the displays in the electric appliance store, but if you are experienced well enough, lifting them and feeling the balance in performing the pouring action would give you some idea as to the ergonomics of the designs. Control of water pouring is part of good tea making. I shall talk more about this in advance tea preparation techniques.
Or going automatic
When consumption volume is a consideration, such as that in a bar or restaurant, or in an office with a large number of workers needing hot water supply, use an instant water boiler that is tankless. Those that are popular with a large (or small) water tank are NOT good. Water that is re-boiled or re-heated constantly does not only taste bad and makes bad tea, but is also a waste of energy. Improperly filtered water may be carcinogenic when re-boiled. There are a few brands of instant water boilers around but since they are a relatively newer approach to boiled water supply, you may have to make some effort to access them.
However, no matter whether it is from the old-style water tank or tankless boiler, water coming out of it is never fully 100°C, for obvious engineering limitations. If a post-fermented tea such as Pu-er is in your repertoire, which is the only tea that requires 100°C water for infusion, you have to be equipped with a kettle (as described earlier) as well.