Water-based food colouring is thin, fluid and runny making it perfect for colouring royal icing, macarons, cake batter, and regular frosting.
Oil-based food colouring on the other hand is more thick and gel-like, perfect for melted chocolate and high fat buttercreams.
Definitely! The pigments and carrier oils tend to separate and unblend over time. We recommend always giving your bottle a shake before every use.
Introducing water or liquids to oil-based dyes can ruin the chemical balance and can cause mixtures to ruin. But you can mix different shades of oil-based colours together to create custom hues.