May 9, 2008
Teatime
I commented on a post on the Bad Language blog, produced by my good friend Matthew Stibbe, earlier this week. He was waxing lyrical about cutting power consumption in his SOHO and mentioned how he prefers to brew tea with freshly drawn water. I pointed out that while this may have benefits it would actually increase his kettle limescale problems through the addition of extra calcium and magnesium ions. The effect will be negligible, but if we are adding up every single kilowatt-second then it could make a difference. Of course, brewing tea is not environment friendly in the first place and we should all really be drinking trapped dew under a hessian bivouac, or somesuch.
Anyway, Matthew immediately followed up my comment with a defence of using freshly drawn water for making a cuppa. He’s a man after my own heart. I’ve done this once or twice in the past and it exemplifies precisely how blogs are if nothing else a dialogue (please don’t prove me wrong by not commenting on this post…)
I’d better qualify my boiling/reboiling comment on his blog. Chemically speaking the difference between starting with freshly drawn water each time will be a simple matter of formation of insoluble calcium and magnesium salts. With freshly drawnn water you’re adding new metal ions, which will effectively add to your limescale. However, the de-hardening of hard water by heating is not a perfect process so some will be retained in the beverage once you pour over tea leaves, but the actual balance depends on how soft or hard is your water supply in the first place.
However, now that I’ve had a glass or two of vino (at the time of writing), it has also occurred to me that there are lots of other, organic, components in fresh tapwater, such as humic acids, and organochlorine compounds (possibly even fluorine compounds depending on where you live). These will be presumably be degraded and/or boiled off with the first boil to a degree. In the second boiling it is more likely that you will get rid of all these flavoursome ingredients from the water. So, perhaps there is something in the use of fresh water for the best cuppa, but it’s marginal given that any flavours in the water will essentially be overwhelmed by the flavour of the tea itself. It’s like worrying about the sounds they leave out when compressing a music file into mp3 format.
Meanwhile, the origins of tea lie in an attempt at “storing” water in Asia, so legend goes, and to protect it from contamination by pathogens (namely cholera, although they didn’t know this as the agent at the time). The polyphenolics and other materials in tea infused into the water are to a degree antimicrobial, but perhaps more importantly the simple act of boiling kills of the microbes quickly and succinctly without any recourse to chemistry.
In the “West”, the equivalent solution to the great clean water problem was the addition of fermenting fruits and the subsequent production of wine or beer depending on the region. It’s thought to explain why westerners have evolved an enzyme to break down alcohol and its metabolites whereas some Asians lack this enzyme system.
Given the choice between a freshly brewed cuppa, I know which I prefer, especially at this time of the evening…now where’s that corkscrew?
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usgarance said,
May 9, 2008 at 2:55 pm
As a matter of taste, fresh water has more oxygen, and it affects the taste of tea. Good tea is made with fresh water at the first boil. It is a bad idea to let the water boil too long (the more you boil it, the less oxygen, the more concentrated unwanted stuff, the more money it costs). A drop of lemon helps with the taste of water which has too much calcium . I learned all this from Agatha Christie, who used to follow her husband every year to Bagdad (he was an archeologist), carrying back and forth her personal teapot.
She used of course the Orient Express. Quality of water on that train is unknown.
Shefaly said,
May 9, 2008 at 6:27 pm
“..please don’t prove me wrong by not commenting on this post…”
Uh-huh, the double negative, especially since you were talking about the Bad Language blog…
It seems to me that a product that combines an ion exchanger and purifier with a kettle would offer a solution to this problem. I found and bought just one such kettle and there is practically zero furriness inside even after months. In my few years in Edinburgh, I had forgotten what the wages of hard water were so this kettle provided welcome relief. Bathrooms, basins etc are another matter altogether.
David Bradley said,
May 9, 2008 at 7:39 pm
Shefaly, don’t just not love double negatives, they ain’t not the funniest thing.
Ion exchanged water is the last thing you want to drink…those calcium and magnesium ions are swapped for sodium (from salt) in such a device. I mentioned this in an item on drinking softened water that was originally on chemspy but I migrated it to here…
db
David Bradley said,
May 9, 2008 at 7:50 pm
I’m really not sure about that whole oxygenation aspect of the taste. Certainly any benefits of boiling too long or too short, reboiling, or whatever are totally negated by adding acid.
db
CMC guy said,
May 11, 2008 at 12:15 am
I’m not a hot tea drinker although used to make Sun tea/ice tea by solar heating a filled glass jug conatining several teabags (which assume is sinful in eyes of real tea drinkers).
Back in my days in Analytical QC wet lab we’d boil the water to remove CO2 for precise titration solutions so could be that if increased H2CO3 would extract components that might alter taste. Seems logical someone at sometime must have done investigation of this nature to profile what differences in tea solutions occur based on water source/treatment so a literature search might find data (if not could be a good school science project if had access to GC?).
I recall in undergrad org lab using steam distillation to extract caffeine from tea as one of the few times people enjoyed smell in the lab. Perhaps only second to when we made a selection of esters with Methyl salicylate/wintergreen being my favorite.