Comments on: All steamed up about reboiling kettles

By: Pogle

Pogle — Tue, 06 Dec 2011 14:08:03 +0000

So who won tea at the Ritz?
A lot of people letting off steam but some rigorous experimentation would be more my cup of tea. It should be easy enough to prove whether there is (a) more or less oxygen in reboiled water and (b) how this affects the process of infusion and finally some blind testing (c) to determine whether there’s any difference at all in the resultant cuppa.

By: matt

matt — Sun, 28 Feb 2010 08:55:49 +0000

I have no idea which tastes the best or the reason for a change in taste, but I was told by the health vistor that I should never use re-boild water for my babies milk solution?! An i’m sure it wasn’t due to a taste comparison held by a group of babies!

For the same reason that you shouldn’t let it boil for more than 1 minute when using it for preparing formula. When it boils some of the water turns into steam and evaporates. This leaves any minerals (including minute traces of lead) remaining in the water in higher levels than in the original (content-tested and approved) water. High concentrations of lead can be especially harmful to children.

Maybe its the same for tea!?

By: Dermott O'Logical

Dermott O'Logical — Tue, 01 Dec 2009 16:23:43 +0000

The reason why great-granny and indeed her granny will have urged that only freshly-drawn water should be boiled when making tea will most probably have stemmed from the fact that iron kettles were at that time in common use, as also was well water. Depending on the actual mineral / dissolved gas content of the water, greater or lesser amounts of iron will have dissolved into the boiling water. Tea contains so-called “hydrolysable tannins” that form blue-black dyes with iron … indeed iron tannate was at one time widely used as an ink. Tea also contains so-called “condensed tannins”, which form green-coloured pigments with ferric ions. So, we may presume that both the colour and the taste of the tea will have been affected by naturally mineral-rich well water and especially so with re-boiled water in which the iron content will have been raised still further. Interestingly, cast iron teapots and kettles can still be bought, these needing to be “seasoned” prior to use to avoid the taste of the metal being imparted. Some manufacturers achieve this by nickel-plating the cast iron. Kettles made of stainless steel or rigid plastic are now more commonly used, so the use of re-boiled water is now less important, but the taste of the tea will nevertheless be affected by the quality of the water … and by the natural variation in the tea leaves from different sources and suppliers.

By: Walter Linton

Walter Linton — Mon, 20 Jul 2009 12:51:35 +0000

RSC
There are several factors here which mean there is no universally correct answer:
1. The area you live in and hence quality of water. In southern England the solids content in water can be as much as 2-3%, where here in central Scotland, its generally < 0.02%, a 100 fold difference! If you live in a much harder water area, you've a much higher chance of buiding up the hardness of the water after consequtive boils if you dont rinse out the kettle.
Tip: Adding around 20 ml of common cheap vinegar to around 100 ml of water in the bottom of your kettle overnight occasionally is a very cheap and effective way of staying scale free. You dont need to splash out on more expensive products but remember to rinse the kettle in the morning!
2. How full you fill the kettle is also key. You should really only boil the water you need. for instance for one cup of tea, pour one cup of water in the kettle, then you'll empty the kettle and avoid build up of concentated deposits which are bound to effect taste. Here we have a solution which is also important environmentally. If we all got used to boiling only what we need it would actually have a measurable effect on reducing the nations energy need and ensure the best tasteing tea!
Best regards, Walter

By: Rodney Priest

Rodney Priest — Thu, 09 Jul 2009 22:43:41 +0000

Even in a very hard water area such as here in Wiltshire, you can consistently make a good cup of tea with ordinary unfiltered tap water if you pay attention to the most important factor — scrupulous removal of all fluffy loosely adhering limescale in your kettle from previous boilings. Make sure your brush has a good big flat end to clean the base and sides of your bottom-boiling kettle every time you make your tea BEFORE you boil the kettle. It takes about 30 seconds and uses about a third of a cup of cold water for rinsing. (Even this little can be saved for watering the plants if you are that much of an environmental puritan.) No need for water filters, pesky little plastic spout inserts that fall out and become mis-shapen so they won’t fit back or even chemical lime scale removers and a delicious cuppa every time. If you are too lazy to do this, expect the disgusting bicarb tasting brew you deserve. As for energy saving overall, your kettle will last far longer and work more efficiently; your nerves and digestion are in for a treat as well.
Science? It could not be simpler. Tough limescale only adheres strongly to the inside of the kettle after several boilings. If you do not brush, you will get enough fluffy suspended lime-scale carrying over into your pot or mug every time you brew to seriously affect the taste.
Reboil or draw fresh? If you live in a soft water area, it matters little. If you live with hard water, and your kettle was clean from last time, the amount of fluffy suspended lime-scale made by one boiling will probably be insufficient to make a diference to all but the most fastidious, so a reboil will not be a disaster.
Want a good cuppa and to be an eco-god/godess? Buy a brush. It’s brilliant.

By: Christopher Reeve

Christopher Reeve — Wed, 08 Jul 2009 11:08:58 +0000

I know I missed the deadline, but just wanted to say that I never reboil water because it tastes disgusting. Maybe I am more sensitive to the taste than other people. Leave boiled water in a kettle for more than 15 minutes and I can guarantee I can taste it. Consequently I only put in the amount of water I need. Unfortunately this means that usually I have to boil water just below the minimum line in order not to waste hot water. Why is it so hard to find a kettle that only boils one cup?

By: Wilf Anderson

Wilf Anderson — Tue, 30 Jun 2009 13:55:35 +0000

Having brewed tea for the best part of 50 years and usually credited with producing a good cuppa, my main conclusion is that the quality of the water outweighs all other factors including boiled and reboiled water. This is based on brewing tea, usually loose leaves of PG Tips , over several years in Newcastle, Maidenhead, Doncaster, Malvern, Brownsville (TX USA), Mexico City and a few other less regular places. I cannot define what I mean by the “quality” of the water but nothing else seems to matter as much to the taste.
Currently I am using Severn Trent water which is filtered through a Brita filter and I use the colour of the tea as a measure of when the filter needs changed. With a new filter the tea is much lighter in colour getting darker as the filter is exhausted. Not sure if the filter is removing or adding something to account for the colour variation.
Incidentally I gave up on ceramic teapots many years ago and now use stainless steel which I never prewarm but I do keep it clean, no brown tannin stains.

By: Charlie

Charlie — Tue, 30 Jun 2009 09:20:24 +0000

Nothing tastes quite so sweet as a penny saved so re-boiling the already warm water has my vote.

By: Bill Edwards

Bill Edwards — Mon, 29 Jun 2009 14:02:42 +0000

There is a philosophical problem with the implied approach to this problem. The correct question should not be is there a chemical explanation to explain why fresh water should be used? but does using fresh water give a perceptible difference in taste? I can assure you it does to me and to most regular tea drinkers.
I have never forgotten in my student days when I had to make tea for a group of British working men. Their initial response could be paraphrased as “This tea is not of the substance and quality demanded” The expressions used as I remember were a series of comments on my personal habits and antecedents!
If we accept the experimental evidence it is proper to try and seek a chemical explanation. The likely chemical explanations can be divided into two classes namely loss of substances on boiling and gain of substances on standing.
The likely candidates for loss on boiling are oxygen and carbonates. The oxygen will interact with the tea oils in the tea while the carbonates will affet the extraction of flavour.
In the gains on standing category are lime scale and trace metals from the kettle. Soft acidic water is more likely to pick up trace metals. Even plastic kettles have metal elements.
This question reminds me of several incidents in the food industry where the management changed the process and did not understand it altering the product. The consumer noticed the difference and stopped buying it.
It has to be remembered that chemistry is an experimental science. It is entirely satisfactory to build theories around experiments but not to discard experiments because of theories

By: Ted

Ted — Mon, 29 Jun 2009 12:45:49 +0000

I heard a lecture a few years ago about plasticisers leaching from plastic kettles – obvious when you think about steam distillation. At the time I had young children and I have seen too many skin grafts following scalds, so I always tipped away the hot water after use. Now I have a bottom-heated kettle and only boil as much as I need.
Calcium in the water (and the milk) makes an unsightly scum on the surface of the tea which stains the cups. Does anyone have an answer to that?