Red, yellow and blue

One of the biggest problems you face when making cold process soaps is colour. The high pH environment of cold process soap making can do some funny things to your colourants. Some colourants, particular natural colourants, will fade to grey. Micas, especially, are a weird bunch. They look beautiful and shiny in their little packet, but once they go into the soap, you never know what’s gonna happen. Some micas turn into the weirdest colours and others will completely fade away into nothing. I’ve had some very disappointing disasters from using micas without previous testing.

The only way you can be certain of a colourant is by doing a colour test beforehand. But that can get expensive. So to make life a little easier for you, I’ll be doing a series of colour tests on micas and other soap colourants available here in New Zealand. And in the end, I’ll put up a handy document for you to download with the different soap colours after curing.

I’m using one of my standard soap recipes, which makes for a nice, solid bar of soap with good lathering qualities. Here’s the recipe:

  • 150 g olive oil
  • 130 g rice bran oil
  • 100 g coconut oil
  • 20 g castor oil
  • 55 g caustic soda
  • 120 ml water

I’m not adding any fragrances or other additives.


For the first colour test I’m using yellow, red and blue granulated soap pigments from Pure Nature. These are available at $12 for 10 g of pigment, and the recommended usage rate is 0.02% of total formulation. This works out to be 0.1 g of pigment per 500 g of soap. Using ratios of 15 cc scoops to 5 ml water, I managed to calculate an amount I could work with.

Pigments are usually water-soluble, so I mixed these in with appropriate amount of water. I then mixed a teaspoon of each colour into the soap, which would give me the exact 0.02% strength I needed.


And this is how the colours appear after a short curing time:

Keep checking back for more colour testing!

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