Why, oh, why didnâ??t I study more chemistry at school. Truth be told, I just hated the subject, but some chemical knowledge would come in handy to answer a burning tea question.

The rec.food.drink.tea group has been debating whether reboiling water affects the taste of your tea, and how. Now, every tea book I know says that you should use freshly drawn water to make tea and reboiling it is a major no-no. But I have recently read Hervé Thisâ?? book, Molecular Gastronomy : Exploring the Science of Flavor. This is Franceâ??make that the worldâ??sâ??leading expert in molecular gastronomy and, beakers in hand, he has proved that many culinary practices guaranteed to improve the flavor of food are little more than myth. His book set me thinking. What if some of the standard practices in tea-making were also a myth? What if you can happily reboil water?

A search on the Internet bore no fruit. Some sites suggest that reboiling water deprives it of oxygen, so the resulting tea tastes flatâ??but others say that most of the oxygen goes with the first boiling and repeated boilings make little difference. Other sites say that reboiling water increases the concentration of mineral, which is not only detrimental to a good cuppa, but also to your health. But then again others maintain that, as you reboil water, minerals precipitate to the bottom of the kettle or pot and the resulting water will be purer. Now, this again could affect the taste of teaâ??but how much? I know that the limestone build-up in my kettle is so much worse when I reboil water than when I donâ??t, but I am not sure how that is going to affect flavor.

To try and solve the conundrum, I set up a little test, making tea with freshly drawn tap water and some Darjeeling GFOP. Then I reboiled the leftover water and made another teaâ??also with Darjeeling GFOP, using the same spoon, colander, steeping times and type of cup. I tasted the two teas blind and found the one made with reboiled water had a marginally more pronounced flavor than the other oneâ??but then I might have given it a marginally longer steeping time without realising it. Other then that, I could tell no major difference.

I suspect that a single reboil isnâ??t going to alter waterâ??s chemical composition so much to have a discernible impact on taste. But reboiling several times might. Since the question still teases my mind, I put finger to keyboard and asked the expertâ??Hervé This himself. I am now hoping he will get back to me and shed some light on this once and for all.

UPDATE: I heard back from This, who was incredibly kind and replied quickly to my fairly out of the blue email. He says that there is no doubt that ions are very important to the taste of water. So if the concentration of these ions increases through multiple boiling, this could definitely affect the taste of said waterâ??and hence of tea. He wasn’t too sure about the impact of dissolved gases. Either way, he suggested running an experiment by filling three vesselsâ??two with water that has boiled once and one with water that has been repeatedly boiledâ??and asking several people to identify the two identical ones. It’s an interesting one. I plan to set it up and report results.