Neon swirl soap

Difficulty: Intermediate
Time: 1 hr
Yields: 1250 g of soap
Mould: standard loaf mould

I recently discovered neon pigments, available from Pure Nature, and they’re perfect for this easy-peasy swirling method to create these stunning soaps. I loved the bright colours so much, that I repeated the same recipe with three different colour combinations. Yellow and green, pink and orange, and a trio of pink, blue and purple. I’ll let you decide which you like the best!

This recipe is an ideal introduction into swirling after you’ve done a few other soaps. The swirling method is really easy to do and pretty much fail-safe. You just need to make sure you’re using a fluid soap recipe, because one of the most common problems encountered with swirling or any technique that takes time, is that the soap starts to thicken and becomes impossible to pour. This recipe I’m using here is my go-to recipe whenever I need time.  It is an adaption of a pure Castile (olive oil) soap, to which I’ve added castor oil (for extra lather) and sodium lactate, a natural additive which helps speed up the hardening of the soap. The result is a lovely mild cleansing bar of soap with all the good qualities of olive oil, but without the long curing time.

Before starting, please read the safety and precautions post, especially since this tutorial requires the handling of caustic soda!

If you have never soap before, I strongly recommend you check out the basic cold process soap tutorial first, and make several other easier soaps before continuing.


ONE: First prepare your lye by weighing out the caustic soda and water. And then, carefully, add the caustic soda to the water (NEVER THE OTHER WAY ROUND!), and stir until the lye water is clear.

Add two teaspoons of sodium lactate, and set aside to cool down. I usually leave my lye solution to cool down in the sink. So in case I knock it over, it will spill into the drains, and the worst thing that will happen is that I have clean drains.


TWO: In the meantime, weigh out the olive oil and castor oil in your soap pot, which can be a large stock pot, a pyrex jug, or even an empty 2L ice cream container. Set aside.

neon colours

THREE: While you are waiting, prepare the colours. Mix 1/2 -1 teaspoon of each colour that you will be using with 1-2 teaspoon of oil (for example olive oil) in a small beaker or container.

If you are using just two colours, use 1 teaspoon each, for three colours use 1/3 teaspoon each, and if you are using four colours use 1/2 teaspoon of each colour.


FOUR: Once the lye has cooled down to room temperature, and making sure you are still wearing your goggles and gloves, carefully add lye to the oils and then, using a stick blender, pulse and stir to thin trace. Make sure you keep the soap at a very fluid, thin consistency. If you’re worried about getting it too thick, you can also use a whisk and beat the oil/lye mixture until it has emulsified (does not separate). I often can’t be bothered getting my stick blender out and will just whisk the soap. (Yes, that works perfectly fine!)


FIVE: Add the fragrance to the emulsified soap mixture and give it a quick stir.

I used different Candlescience fragrances for each of the colour combinations:

  • green and yellow: coconut lime
  • orange and hot pink: mango and tangerine
  • white, bright pink, blue and purple: sweet pea


SIX: Separate the soap into roughly equal portions depending on the number of colours you are using and add the colours to each pot of soap. Using your stick blender or whisk, briefly mix each pot until the colour is evenly dispersed through the soap.

Note for the white/pink/blue/purple soap, I left one portion uncoloured.

SEVEN: To create the swirls, pour a line of one colour along the length of your mould. You can either pour to the line on the side or the centre, it’s up to you. If you pour it in the centre, you’ll have a roughly symmetrical soap, like the white/pink/blue/purple soap, and if you have the line more to one side, it will be more skewed, like the yellow/green soap below.

Next pour a line of another colour INTO the same line of soap that you just poured. So instead of pouring the soap next to each other, you keep pouring into the same line over and over again, and this pushes the colours to the side and creates the swirls that you see in the soaps.

You can be a bit more daring, and instead of one line, create two lines into which you pour the soap, just like I did with the orange/pink soap (further below). Or you can change halfway and start a new line on the other side. You can’t really do anything wrong. Even if you don’t hit the previous line of soap exactly, it doesn’t matter, you’ll still get your swirls.

Keep pouring, alternating the colours, into the same line until all the soap has been used up.

Leave the soap somewhere warm and dry, out of direct sunlight, to cure.

EIGHT: After 2-3 days, check if the soap has hardened and isn’t sticky and soft anymore. Don’t be tempted to unmould to soon, like I was with the orange/pink soap. The hardest part of creating swirl soaps is waiting for the soap to become hard enough to unmould. Once it is hard enough, carefully unmould, and cut it into bars. The bars of soap will need a further 6-8 weeks to cure before they are ready for use.


Neon swirl soap

  • Difficulty: intermediate
  • Print
Before starting, make sure you wear protective goggles and gloves and work in a well-ventilated area, free from any distractions!


  • 950 g olive oil
  • 50 g castor oil
  • 128 g caustic soda
  • 280 g water
  • 2 teaspoons sodium lactate
  • 1/2 to 1 teaspoon each of the neon colours you are using
  • 30 ml fragrance


  1. Measure out 280 g of water into a heat proof Pyrex jug. Weigh out 128 g of caustic soda and carefully add it to the water, avoiding any splashes. Gently stir until all the caustic soda has dissolved and the lye solution is clear.
  2. Add two teaspoons of sodium lactate to the lye solution. Set aside to cool down.
  3. Weigh out the olive oil and castor oil in your soap pot. Set aside.
  4. Prepare your essential oil blend. Set aside.
  5. Mix 1/2 to 1 teaspoon of each colour with 1-2 teaspoons of olive oil in a separate pot. The exact amounts depend on how many colours you are using. Set aside.
  6. Once the lye has cooled down to room temperature, and making sure you are still wearing protective goggles and gloves, carefully add the lye to the oils.
  7. Using a stick blender or whisk, stir until the oil/lye mixture has emulsified.
  8. Add 30 ml of fragrance and give it another quick mix with the stick blender.
  9. Divide the soap into roughly equal portions and colour each portion with one of the colour/oil mixture. Briefly mix each pot a quick pulse with a stick blender or whisk until the colour is evenly dispersed through the soap.
  10. Pour a line of one colour along the length of the mould.
  11. Pour another colour of soap into the previous line of soap. Keep repeating the colours until all the soap has been used up.
  12. Place the soap in a warm, dry area to cure.
  13. After 2-3 days, check if the soap is firm enough to unmould. Remove from mould and cut into bars. The bars will need further curing for about 6-8 weeks until ready for use.


  1. Thank you Shirley! Depending on where you are, you might be able to get the neon pigments in your country as well.

  2. I so wish I could get those lovely neon w/o such a high expense shipping across the world. Your soap is so beautiful! Thank you for sharing your recipe too!

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