Food colouring

In detail

Food colouring is unusual among household stains in being almost pure dye in water, with no fat, protein or particulate to complicate it. That makes the diagnosis simple and the outcome binary. On a non-porous surface it wipes away with water alone if caught promptly, because there is nothing holding it there. On anything porous or absorbent — unsealed wood, grout, a plastic chopping board, a laminate worktop with a worn edge, cotton, a nylon carpet fibre — the dye is taken up into the material and the mark is no longer on the surface at all. The carpet institute's entry reflects the simplicity: detergent solution, warm water, vinegar solution, professional, with no solvent branch anywhere in it. The vinegar step is doing what it does throughout that database, lowering alkalinity rather than attacking the dye. Where colour has genuinely penetrated, the honest options are an oxidising treatment appropriate to the material or accepting the mark, and gel colours used in baking are worse than liquid ones because the concentration is far higher.

Why

• Food colouring is explained by Capillary absorption
• Food colouring is explained by Dye migration and colour bleeding