Homemade rainbow soap (cold process)

Hold the whole rainbow with this homemade soap recipe

For some, a rainbow is a passage to another world. For others, it hides a pot of gold. Some even think that marvellous unicorns and ponies roam it to reach their magical country. And let’s not forget, the rainbow is also a symbol of love and tolerance… Whatever it evokes for you, our Heavenly Hammock soap recipe unites all lovers of this wonderful natural phenomenon!

Its shimmering colours and citrus-floral bouquet make this homemade soap simply irresistible! Thanks to the castor oil, it foams up nicely to create a beautiful lather, perfect for gently washing your body while leaving a delicate scent on your skin.

Nevertheless, if you’ve never tried making soap before, we don’t recommend that you start with this recipe! To succeed with it, you must have already mastered trace. What’s more, this decorative soap requires a lot of patience… But we promise, it’s worth it!

With this DIY soap, you’ll finally discover what’s hiding at the end of the rainbow!

How to make homemade soap?

Before you begin

Sodium lactate will solidify the soap more quickly, but it also accelerates trace. We use it here so that the soap can be unmolded more quickly (in 24 to 48 hours).
In this cold process soap recipe, we will be working with a light trace only, in order to create nice straight, even layers. It is thus important to use the immersion blender in a moderate way so as not to accelerate the reaction.

Ingredients

Oil mixture/blend

156 g (6.88%) extra-virgin organic olive oil
552 g (24.35%) extra-virgin organic coconut oil
552 g (24.35%) organic sunflower oil
96 g (4.23%) organic castor oil
96 g (4.23%) sweet almond oil
48 g (2.12%) stearic acid

Sodium hydroxide solution

436 g (19.23%) demineralized water
218 g (9.62%) sodium hydroxide
25 g (1.1%) sodium lactate

Superfatting

42 g (1.85%) mango butter

Essential oil mixture

16 g (0.71%) palmarosa essential oil
26 g (1.15%) lemon-scented eucalyptus essential oil

Colourants for each coloured layer

Purple layer
- 0.50 g (0.02%) ultramarine blue
- 0.25 g (0.01%) light red oxide
- 0.20 g (0.01%) ultramarine violet
Blue layer
- 0.50 g (0.02%) ultramarine blue
Green layer
- 1 g (0.04%) green oxide
Yellow layer
- 0.60 g (0.03%) yellow oxide
Orange layer
- 0.45 g (0.02%) mars orange
Red layer
- 0.50 g (0.02%) light red oxide

Tools

Components to make a double boiler
Scales, accurate to 1 g and 1g
1 large stainless steel bowl
3 small stainless steel bowls (one for the sodium hydroxide, one for the sodium lactate, and one for the mango butter)
2 large Pyrex measuring cups or two HDPE pots for the sodium hydroxide solutions (with a capacity greater than 500 ml each)
1 silicone spatula
6 mini silicone spatulas
1 thermometer
6 measuring funnel pitchers (900 ml each)
7 ramekins (1 for the essential oils, 6 for the colourants)
Several spoons for the colourants
Several pipettes for the essential oils
1 immersion blender
1 large wood soap mold with silicone insert
Protective soapmaking gear

Steps to follow

Prepare and sterilize your equipment and workspace.
Take the necessary precautions for using sodium hydroxide safely.
Prepare the sodium hydroxide and sodium lactate solution by first weighing the demineralized water, sodium lactate, and sodium hydroxide in three separate containers. Next, add the sodium lactate to the water, then gradually add the sodium hydroxide into the aqueous mixture in a large Pyrex cup or HDPE pot. Set solution aside to cool.
In the first ramekin, weigh the essential oils with a pipette and mix together.
In the six other ramekins, weigh the colourants using the spoons. Be sure to use a different spoon for each colourant or to clean your spoon well between measuring each colourant so as not to combine the pigments.
Weigh the mango butter for the superfatting in a small bowl and melt on the double boiler.
Weigh the coconut oil and stearic acid in the large stainless steel bowl and melt on the double boiler. Once melted, remove from heat and add the oils (olive, castor, sweet almond, and sunflower).
In each measuring funnel pitcher, disperse each colourant into 250 g of the oil mixture obtained in step 6.
Mix the colourants into the oils well with the silicone spatula. Next, to avoid any clumps forming, disperse the colourants with the immersion blender. Remember to clean the blender between each colour so as not to mix them.
In the second Pyrex measuring cup or HDPE pot, weigh 110 g of the sodium hydroxide solution for the first colour (purple).
When the oil mixture and sodium hydroxide solution have both cooled to a temperature of 26–29°C, add the 110 g of the sodium hydroxide solution to the 250 g of purple oil mixture. Stir with the spatula to combine.
When the sodium hydroxide and oil mixture is homogeneous, mix with the immersion blender in little 5-to-10-second bursts until it reaches light trace. You must be patient for this step!
When the soap batter has reached light trace, add 7 g (8.5 ml) of the essential oil mixture and 7 g of the superfatting oil to the batter with the pipette. Mix well with the silicone spatula. When the consistency of the mixture is homogeneous, mix again with the immersion blender in 5-to-10-second bursts while regularly checking the trace.
When the trace is light and the consistency is still liquid, it’s time to pour the soap batter into the mold. This way, each layer will be perfectly straight and you’ll achieve the intended pattern.
Wait until the layer has hardened. To check its hardness, lightly touch the soap later with your finger, while still wearing your protective gloves, of course! The soap should not stick to your finger.
Once the layer has hardened, repeat steps 9–14 for each colour. For a successful rainbow pattern, the next layers should be poured in the following order: blue, green, yellow, orange, and lastly red.
Remember to clean the immersion blender between each colour so as not to mix them.
Cover the soap for 24–48 hours.
Wear gloves to unmold the soap. Cut and leave soaps in a cool, dry place for 4–6 weeks to cure. Now you can enjoy your homemade soap!