May 9, 2008
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?