You paid money for that tea. Maybe even a lot of money!
So here are some simple, easy-to-follow, considerations to ensure you correctly match your water to your tea leaves (especially useful for that first brew of the day when you’re already late for work).
Do not, do not, use untested water, or unfiltered water, or distilled water, or too hard of water, or too soft of water, or hot water, or standing water, or water that has already been boiled, or anything that might actually come out of your tap because you need whatever it is that you do not currently own. And do not, do not, use water that is too acidic, or too alkaline. And do not, do not, use water that has the wrong amount of chlorine, or calcium, or iron, or magnesium. And do not, do not, heat non-boiled water that’s been standing in your electric water kettle, or heat water in your electric water kettle that hasn’t been cleaned since who knows when, or reheat that standing water that’s already been heated a couple of times in your electric water kettle. And do not, do not, let your water boil too long, or too little. And do not, do not, let the boiled water sit too long, or too little. In a nutshell, just don’t.
Unless, of course, you live happily on the edge—indiscriminately tossing tea leaves into whatever receptacle is at hand and brewing them nilly willy with whatever water that has been heated to whatever for however long.
And if you love your end product, who really cares?!
But why not extract the best possible flavor out of your tea leaves?
And that involves your choice of water—an issue that Chinese tea master Lu Yu addressed in the definitive book on tea, Ch’a-ching (The Classic of Tea), published in 780 C.E. And his instructions are certainly no easier to follow than those given above!
Lu Yu recommended water that was gently tumbling over rocks as it came down from the mountains, neither too turbulent nor stagnant, so definitely not like the river shown here!
Further, it wasn’t to be water that:
sank into the ground without finding an outlet, for from the seventh through the ninth months there might be harmful poisons that have emanated from dragons there. (Sōshitsu 1998:22)
It seems entirely reasonable to me that toxins may settle in undisturbed water, and in 780 C.E., dragons were possibly as good an explanation as any.
Lacking the proper mountain water, Lu Yu advised using river water—but drawn from the middle of the river, well away from human settlements, again demonstrating Lu Yu’s astuteness. Finally, if stuck with well water, Lu Yu wrote that the first few buckets drawn should not be used.
Over 1,200 years ago, Lu Yu understood that clean, fresh, moving water makes the best tea. Therefore—
You may not want to use water that’s been sitting in your kettle for awhile, especially if your electric kettle has mineral buildup, which eventually seeps into the standing water. Microorganisms are less likely to grow in moving water, so water that’s been sitting around for awhile isn’t ideal—but boiling the water ought to take care of any microorganism situation anyway!
Boiling concentrates impurities—yet whether you drink all the water in the kettle at once or a cup at a time, in the end you’re drinking the same water, right? And in the U.S., anyway, we can generally assume our tap water is safe so it’s not like you boil water and end up with toxins (note: this is not to minimize instances when this tragically has not been the case, as with the Flint water crisis).
However, boiling can transform some desirable solubles (such as calcium) into undesirable insolubles, so for that reason you probably don’t want to keep boiling the same water over and over (Harbowy 2012).
These make a real difference in tea—too few and the water and resulting tea taste flat but too many (think iron!) and they interfere with flavor; some solids work well with certain teas whereas others don’t (some teas were originally developed specifically for local water). You want water that’s somewhere between hard and soft, and for many of us in the U.S., our tap water now falls within that range.
If, however, your tap water is hard, solids will cake up in your pipes and hot water heater, which is why you want to use cold water from your tap rather than hot. (Also, cold water is less likely to contain lead.)
I’ve often heard that you want fresh cold water because it has more oxygen, and that you shouldn’t reboil water because that water has been deoxygenated—but this isn’t quite right.
While it is boiling, water has little to no oxygen, but when that water starts cooling down, “oxygen begins to exchange with the surface of the water . . . [and] if you shake the container . . . while it cools, the level will quickly rise because of the surface area exposed to air” (Harbowy). In other words, that boiled water will re-oxygenate.
Further, Harbowy argues that it’s unlikely that oxygen affects tea flavor, partly because there’s little to no oxygen in hot water (and if you boil the water for a longer period, there’s still no oxygen in it), and partly because this seems to be more a tradition or perception than a scientifically demonstrated parameter.
A pH level that is slightly alkaline is better than an acidic water (pure water has a neutral pH level) because it will interfere less with the tea flavor. However, most tap water in the U.S. aims for a slightly alkaline level so this isn’t an issue.
you end up getting used to whatever water you are using, and generally notice a difference only if you go somewhere else, with a different water source, and brew the same tea. And if you find better water, say from your in-laws’ well, it’s not like you can just cart buckets of their water home with you (easily, anyway)!
There’s bottled water, but for many of us, testing indicates that our tap water is as safe, or safer, than bottled water. And there’s the environmental concern of buying water packaged in plastic containers when my own tap water is just fine.
Filters may help, and certainly tea and coffee shops run their water through highly sophisticated systems, but we can’t really replicate that at home.
Also to keep in mind, Lu Yu made valid points at a time when water was likely to be contaminated with truly nasty stuff, but today, for those of us privileged to have ready access to safe tap water, this is sort of a moot issue.
Still, if you are not satisfied with your brewed tea, your water may be a place to start.
–The Japanese Way of Tea, by Sen Sōshitsu XV, translated by V. D. Morris, University of Hawai’i Press, Honolulu, 1998.
–”pH of water for tea,” International Tea Masters Association, 2018.
–Matt Harbowy, answer to “Why do tea instructions suggest starting with cold water: You boil it, so does it really make a difference?” on Quora, December 30, 2011.
–Matt Harbowy, answer to “Why should water for tea only be boiled once?” on Quora, May 24, 2012.
–Why are you not supposed to use twice boiled water for tea?,” by Karl Smallwood, Today I Found Out, June 19, 2016.