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Cabbage Blue Food Dye

Peer reviewed by UK recipe editorsAuthored by UK recipe editorsOriginally published 28 Jan 2026

Meets Patient’s editorial guidelines

This clever vegan food colouring allows you to create a striking blue hue for your bakes without relying on synthetic dyes. By simmering red cabbage into a concentrated syrup, you harness its natural pigments, which magically transform from deep purple to a vibrant blue when balanced with a touch of bicarbonate of soda. It is a brilliant, chemical-free technique for any home baker looking to add a splash of colour to their kitchen projects.

Perfect for tinting royal icing, buttercream, or frostings, this homemade dye is as practical as it is fascinating to make. Because it is plant-based, it fits seamlessly into vegan or health-conscious lifestyles, providing an earthy yet effective alternative to shop-bought vials. Use it sparingly for soft pastels or build the intensity for a more dramatic finish on your favourite cakes.

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Ingredients for Cabbage Blue Food Dye

  • 1/2 small head of red cabbage, coarsely chopped

  • 100g sugar

  • 1/2 teaspoons bicarbonate of soda

How to make Cabbage Blue Food Dye

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Bring cabbage and 3 cups water to a simmer in a medium saucepan over medium-low heat and cook until cabbage is soft and liquid is reduced by about a third, 20–25 minutes.

Remove cabbage with a spider or slotted spoon; discard. Add sugar to cabbage liquid and simmer, swirling pan occasionally, until liquid is a very deep purple and has reduced to about 240ml , 10–15 minutes. Let dye cool, then stir in bicarbonate of soda. Mix into frosting or royal icing to make desired colour.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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