Food dyes

[ffutures]

In my day job we use soluble food dyes for experiments on e.g. transpiration, the way that plants take up water from the soil.

Waitrose and Tesco no longer seem to stock the food dyes (Langdales) we usually use for these experiments – they’ve replaced them with Dr. Oetker dyes that doesn’t seem to work at all, because they're a suspension of insoluble natural colourings; they're presumably OK for cooking, but they're pretty much useless for this experiment.

Can anyone suggest alternatives, preferably in several colours? Or point me at a source for the Langdale colours or something like them? We need something non-toxic (which hopefully applies to all food dyes), at least two or three colours - it would be useful to have red, blue, green and yellow - and non-toxic to plants, which rules out some of the chemicals I might otherwise use. Someone has suggested dyes used by soap makers, any other ideas?

Comments

[turol.livejournal.com]

Don't know about ready-to-buy stuff but how about going back to basics?

See if you can find some blueberries, crush them and use the juice as dye. Be careful though, it's almost impossible to get rid of the stains if you spill this stuff on your clothes.

[ffutures.livejournal.com]

Interesting idea, might be worth trying if we can't get the right e-numbers.