Teatime

Chocolate teapotI 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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12 thoughts on “Teatime”

  1. Glad you spotted the chocolate teapot Jon. Yes, there is an awful lot of received wisdom that gets upgraded to scientific know-how in retrospect. I don’t think there are any proteins in milk that are severely denatured to the point of affecting taste. If they were the whole Horlicks/Ovaltine market would have dried up years ago. More worrying is that someone might add lemon to tea containing milk, that definitely will denature milk proteins causing curdling and little flecks of milky stuff in your tea.

    db

  2. What? The Pyramid bags are another clever marketing ploy, and their three-dimensional tea filtering bears no relevance on the taste? I’ve been buying those things for years – they clearly work, if only in a placebo kind of way. Placebags?

    Having recently moved to the Big Smoke, I’ve found the quality of my tea has gone significantly downwards; a far cry from the soft waters of the Land of my Fathers where I grew up. I note the recipe states using ‘softened’ water, which I agree is no substitute for naturally soft water. I have to conclude, from personal experience, that one can only get a decent cup of tea in Wales. :)

    Perhaps I should have read that press release before I linked to it – the Loughborough man concentrates on adding milk before water “because denaturation of milk proteins is likely to occur”, but this isn’t the historical reason. In the bad old days, pre-porcelain, the milk was added first because the hot tea would crack the cheap china cups that were available to the masses.

    And so, bereft of science but heavy on history, this rambly post ends. It seems it was about as useful as the teapot pictured in this post, apparently made of chocolate!

    Jon

  3. Nice to have some support for my negligible oxygenation comments. You’re right about tea making varying from region to region, my wife insists on warming the pot, but my Dad is not worried about simply dunking a teabag in the cup.

    Incidentally, Tetley marketed pyramidal teabags a while back for a fresher flavour, but on the box it said it didn’t matter if the teabag didn’t sit fully pyramidally erect as you’d still get a full-flavoured cuppa. Basically proved that the shape was purely a marketing ploy.

    db

  4. Preparing tea needs boiling of water. After boiling dissolved gases evaporate and minerals precipitate . we do not relish boiled water even after cooling.(even plants may not relish boiled and cooled water because if such water is put to some indoor plants like moneyplant which is commonly grown in Indian houses turns yellow within one or two days). Probably oxygen has no role in the taste of Tea.Tea making requires primarily the leafy preparation(not the powder), thick tea pot either of porcelain or terracotta pot and the tea should be prepared slowly(even though there is little waste of energy). A white porcelain teacup is preffered. Allowing the hot tea in the tea cup is a good option even though there is an extra work of removing the cream which forms on the surface after cooling.However tea making varies from region to region and person to person.

  5. Makes interesting reading Jon, but filtered and softened water, as you know are not the same thing. To soften water you have to chemically remove the ions that make the water hard, which involves ion exchanging them (it’s either that or heating the water to precipitate those ions as salts (limescale)), which brings us full circle. To avoid limescale scum on the top of a cup of tea, it’s simpler to have a kettle filter that catches the scum while pouring into the pot.

    As to the oxygen levels, I believe that’s a red herring, is there a research paper on that aspect that you could cite?

    db

  6. May I recommend the experts’ opinions, summarised here:

    http://www.rsc.org/pdf/pressoffice/2003/tea.pdf

    If anyone is more eminently qualified to give the recipe for a Perfect Cup of Tea than Oscar Wilde, then surely it must be the Chemistry Department at Loughborough University ;-)

    I’ve tried it myself, and it works like a charm. The more ceremony in a cup of tea, the better, of course – the Eastern civilisations correctly observe this still. IMHO, naturally.

    Jon

  7. 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.

  8. 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

  9. 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

  10. “..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.

  11. 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.

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