Time: 1 1/2 hrs
Yields: 1200 g soap or 10 bars
One thing I do miss from living in Europe is the dark, cold, clear winter nights. I was never lucky enough to be far enough up north to see the northern lights, the one time I did go was in summer, but I can imagine what an astonishing sight it must be.
This soap uses a variety of colourants to recreate the Northern Lights. I’m using activated charcoal for the black background, blue and yellow soap pigments for the green and blue light, and blue glow in the dark pigment for the light glow. And the soap really does glow in the dark with a beautiful blue glow! The glow in the dark pigments from Pure Nature are classed as skin-safe and are as such safe to use in soaps, and work both in melt and pour soap bases as well as cold process soap making. The soap mold I’m using for this soap is the silicon loaf mold with wooden support box available from Pure Nature.
The colour technique I’m using in this soap is a simple layering technique, where you scoop the coloured soap alternating into the mold in a random fashion.
If you have never made cold-process soap before, I strongly suggest you check out the basic cold process soap tutorial first.
Before starting, please read the safety and precautions post, especially since this tutorial requires the handling of caustic soda!
Prepare the blue and yellow granulated soap pigments as outlined here. I like having my three main colours (red, yellow, blue) already pre-mixed and I keep them in the fridge for storage, so that when I need them, they’re already prepared and ready for use.
In a small container, mix 1 teaspoon of blue glow in the dark pigment with 1 teaspoon of water.
Set the colours, glow in the dark mixture and the activated charcoal aside, ready for use later.
ONE: To prepare the lye, first measure out the water in a heat proof Pyrex jug. Then, in a separate container (I use a little plastic cup for this), weigh out the caustic soda. Make sure you are wearing protective goggles and gloves. Carefully, add the caustic soda to the water (NEVER THE OTHER WAY ROUND!), and avoiding any splashes, stir until the lye water is clear. Add two teaspoons of sodium lactate, which will help harden the soap and set aside to cool.
TWO: In a separate large Pyrex jug or pot, weigh out the coconut oil, and heat in the microwave on high for 1 minute or until it has completely melted.
THREE: Weigh out the olive oil, rice bran oil and castor oil to the now-liquid coconut oil , and give it a quick stir. Set aside until the lye has cooled down to room temperature. You will want to make sure that you are soaping at no more than 30 degrees, so that you can slow down the thickening of the soap while you are putting the soap together.
FOUR: Make sure you are still wearing your goggles and gloves. Once the lye has cooled down to room temperature, carefully add it to the oils and then using a stick blender, pulse and stir until the oil/lye mixture has emulsified (does not separate).
FIVE: Add the fragrance and using a stick blender, give it another quick pulse to mix the fragrance into the soap, but make sure you keep the soap at light trace (fluid consistency). Because we’re doing colour work, you want to prevent the soap from thickening too soon.
The fragrance I’m using is called Garden Mint from Candlescience Fragrances. It’s a beautiful fresh, clear fragrance but with a rounded, slightly floral base to it. I think it matches Northern Lights perfectly! 30 ml (1 oz) of fragrance is sufficient for this soap, because mints can quickly become too overpowering, and I wanted a subtle fragrance in this soap.
SIX: Next, pour about 1 cup each into three different containers (I’m using my small Pyrex jugs for this), leaving approximately 3 cups in the main soap pot.
To the main pot with about 3 cups of soap in it, add 1 tablespoon of activated charcoal and 1 tablespoon of water, and give it a good stir until the charcoal and water is well incorporated into the soap. The reason we also add a tablespoon of water to this soap is to off-set the extra water the other 3 parts will have added to it, and prevent an unequal water balance in the soap. This will help avoid glycerin rivers.
To one of the remaining containers or jugs with 1 cup of soap, add 1 teaspoon of blue soap pigment solution. To the other container, add approximately 3/4 yellow soap pigment solution and 1/2 teaspoon blue soap pigment solution. And to the last container, add the pre-mixed glow in the dark and water mixture. Give all three containers a good stir to blend in the colour.
SEVEN: You should now have 4 colours, approximately
- 3 cups of black soap
- 1 cup of blue soap
- 1 cup of green soap
- 1 cup of glow in the dark soap
EIGHT: First, pour or scoop a layer of black soap into your soap mold and then start putting your soap together, by alternately scooping the different coloured soap into your mold. Layer the colours both over each other and next to each other, in a random fashion, making sure you buffer sufficient black soaps between the coloured layers. Keep scooping until you have used up all the soap.
NINE: Drizzle the last few bits of soap over the surface, and then using a chop stick swirl the surface of the soap. Spritz with 99% isopropyl alcohol to prevent soda ash from forming on the surface. Place the soap somewhere warm and dry, but out of direct sunlight, to cure. I like using the hot water cupboard to cure my soap, which is the driest spot in our house. But when the weather warms up in summer and becomes terribly humid (especially January and February), I move my soaps into our hallway with a dehumidifier right next to them. Even cold process soaps can sweat in extreme humid weather!
TEN: After 2 or 3 days, check if the soap has hardened and isn’t sticky and soft anymore. Carefully unmold, and leave to dry out for another couple of days before cutting it into bars. The bars of soap will need a further 8 weeks to cure before they are ready for use.
- 500g olive oil
- 250g coconut oil
- 200g rice bran oil
- 50g castor oil
- 136g caustic soda
- 250 ml water
- 2 teaspoons sodium lactate
- 30 ml garden mint fragrance from Candlescience Fragrances
- 1 tablespoon activated charcoal
- blue and yellow granulated soap pigment
- 1 teaspoon blue glow in the dark soap pigment
Prepare the blue and yellow granulated soap pigments as outlined here. Mix 1 teaspoon of blue glow in the dark pigment with 1 teaspoon of water. Set colours and activated charcoal aside, ready for use later.
- Measure out 250 ml of water into a heat proof Pyrex jug. Weigh out the caustic soda and carefully add it to the water, avoiding any splashes. Gently stir until all the caustic soda has dissolved and the lye water is clear.
- Add 2 teaspoon of sodium lactate to the lye water. Set the lye aside to cool down.
- In a large heat proof Pyrex jug or pot, weigh out the coconut oil. Heat in microwave (if Pyrex jug) or stove (if pot) until all the oil has completely melted.
- Add the olive oil, rice bran oil and castor oil to the now-liquid coconut oil, and give it a quick stir.
- 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.
- Using a stick blender, pulse and stir until the oil/lye mixture has emulsified.
- Add the fragrance and give it another quick pulse with the stick blender to mix in the fragrance. Make sure the soap remains fairly fluid (at thin trace)!
- Pour approximately 1 cup of soap into three separate containers, leaving roughly 3 cups of soap in the main pot. You should have 4 containers with soap in total!
- To the main pot with 3 cups of soap, add 1 tablespoon of activated charcoal and 1 tablespoon of water and stir well to incorporate the charcoal evenly into the soap.
- To the three containers containing 1 cup of soap each, add colourants as follows, and stir each pot until the colour is evenly distributed throughout the soap:
- 1 teaspoon of blue pigment solution
- 3/4 teaspoon of yellow and 1/2 teaspoon of blue pigment solution
- all of the prepared glow in the dark mixture
- Pour or scoop a layer of black soap into the soap mold.
- Then alternating colours, scoop the soap into the mold, layering them over each other and next to each other in random fashion, until all the soap has been used up.
- Drizzle the last remaining soap on the surface, and using a chopstick swirl the surface of the soap, and spritz with 99% isopropyl alcohol.
- Leave the soap to cure for several days.
- After 2-3 days, check if the soap is firm enough to unmold. Remove from mold and leave to dry for another couple of days, before cutting into bars. The bars will need further curing for about 8 weeks until ready for use.