Friday, 10 February 2012

Cabbage colours

Some day I will get around to writing an erudite piece about the vital difference between delegates and representatives in the context of the C&RT elections, but tonight I've been sidetracked again by... ooh, look at the pretty colours...

Tonight I steamed some red cabbage, like you do, and was amazed when I came to do the washing up. The steamer in which the cabbage had been sitting was a glorious deep violet, while the water below had turned bright cyan blue.

3 comments:

  1. We're on kids' science here: the pigment in red cabbage acts as an indicator of acid/alkali. I suspect that pH in your pan has higher pH than the stuff left behind on the collander. Maybe as a result of a reaction with the metal of the pan, or just because the stuff on the collander has been concentrated by evaporation.

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  2. Oh wow.
    The pan is stainless so could it be to do with the pH of the water itself?
    This was a steamer, so the cabbage in the top bit would only have been exposed to the steam, which presumably would be much purer than the water in the pan below.
    In which case it would have been interesting to see whether it would have been different back in chalky Sussex.

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    Replies
    1. So the water in the pan has dissolved in it whatever is in the water supply, plus whatever has been leached out of the cabbage as it cooked or was on the surface of the cabbage. The water in the steamer has the same, except that it won't have the water-supply originated material and the cabbage stuff will be at a different, probably higher, concentration. That's certainly a big-enough difference to generate different pH in the two places, and yes, what's dissolved in the water makes a difference, so it could be different in Sussex.

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