Oil based powder dyes are used to colour white chocolate. The Dye Pack B contains 4 x 1gm phials in Red, Yellow, Orange and Green. Simply add a shake of powder to your melted white chocoate and stir. Keep adding more powder until you get the desired colour. The powder does not have a taste.

You can also use these powders to colour icings including: Ready to Roll Fondant icing, butter frostings, modelling paste, flower paste. 
You can make a liquid paste but adding a drop or two of boiling water to some powder colour or mixing the powder dye straight in and kneading the colour through