with knife and fork » pH http://withknifeandfork.com a blog mostly about food Mon, 25 May 2015 16:04:21 +0000 en-US hourly 1 https://wordpress.org/?v=4.1.41 A little bit of chemistry http://withknifeandfork.com/a-little-bit-of-chemistry http://withknifeandfork.com/a-little-bit-of-chemistry#comments Tue, 17 Mar 2009 21:19:00 +0000 http://withknifeandfork.wordpress.com/2009/03/17/a-little-bit-of-chemistry/ Continue reading A little bit of chemistry]]>
I took this photo of the water after I’d steamed some red cabbage at the weekend because I thought it was such a beautiful colour.

And then I got to wondering what chemistry is going on that means that a lovely deep red cabbage produces blue  water (with slight hints of green – it was bluer in reality than the picture shows – more photography practice for me). It turned out to be pretty simple and a quick bit of googling lead me to the answer.


It’s all about the pH of the water – and in fact red cabbage isn’t always red depending on the acidity or otherwise of the soil it’s grown in. I then found a chart of the most recent water tests for the area where I live on the Thames Water site – how cool is this – you put in your postcode and it takes you to the stats for your area – oh such delightful push of button geeky info.

And on about.com I found a table that tallying the water colour to the expected pH – which was pretty accurate an estimated pH 8 compared to measured average of 7.8. I’m impressed (some might suggest its easily done but hey). 

Science made interesting? Maybe.

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