If done properly, it can make a huge difference to your homemade birthday or celebration cakes, and make the recipient very happy!
Do your reds turn out pink and your blacks turn out grey? You need to buy good quality colourings to get strong colours, particularly primary and secondary colours. Shops that sell cake decorating equipment have these colourings; they’re in tiny plastic jars labelled gels or pastes. They’re imported, highly concentrated and will last for a long time, and many homeware and craft shops sell them too.
White, fluffy icings colour easily, especially in pastel shades. Begin adding the colouring into these types of icings when you’ve almost finished beating them.
Start with only a portion of a drop – you can always add more. Use the tip of a skewer to dab the colouring onto the icing, then beat it in, and keep scraping the icing down from the side of the bowl. Royal icing also colours easily.
Butter-based icings, such as butter (or Vienna) cream, are tricky to colour subtly because they have a yellow-coloured base, so that’s going to affect whatever colour you choose. Pinks are the trickiest to get just right; use a pink colouring with a slightly blue base, such as a rose pink, as red colourings are more liable to turn the butter cream a salmon colour rather than pink.
Glacé icings should be coloured before they’re warmed, and if the recipe contains butter it will influence the final colour in the same way it does with butter cream.
Pre-made fondant icing
Start with a test piece: break a little from the bulk of the icing and cover the rest with a bowl to keep the air away from it. Work a tiny amount of colouring through the little piece of icing so that you get the feel of it and can see how the colouring is going to take – you might be surprised at how little colouring you need. Gentle kneading is all that’s required.
Knead the test piece of icing, along with more colouring through the large piece of icing until the colouring is evenly distributed.
If you want to leave the icing while you do other things, or even overnight, enclose it tightly in plastic wrap to make it airtight and set it aside it at room temperature until you’re ready; even a day or two is fine.
Colours change overnight
If your frosting is butter-based, like butter cream, it can be made and coloured a day ahead. The catch is, though, that the colours can lighten or darken overnight. Some brands of liquid colouring are less stable than others but gels and pastes seem to be able to hold the colours best.
Colour the quantities of frosting you need for the cake, cover the bowls tightly with plastic wrap and leave them to stand overnight at a cool room temperature – not in the fridge. Always keep some uncoloured frosting in reserve in case you need to add some to a colour that has darkened too much for your cake. Next day, have a look at the colours and then you can change them to suit if they’re not quite right.
It’s well worth paying the little extra you need for good quality colourings if you want perfect results.