Solid Shampoo Bar with SCI: the Homemade Recipe, Step by Step

An SCI solid shampoo bar is made without lye, in about thirty minutes: you melt the ingredients, mix them in the right order and pour. The secret comes down to one rule: dissolve the SCI first, in the hot water, before anything else. Here is our recipe for a bar of about 90 g.

At a glance

• Cleansing base: SCI, a mild surfactant derived from coconut oil
• Working time: 30 minutes
• Ready to use: after about 2 to 3 days of drying
• Yield: one bar of about 90 g
• Difficulty: easy, no caustic product

Shampoo bar or soap for your hair?

A soap, such as Aleppo soap, is created by the reaction of an oil with sodium hydroxide. An SCI shampoo bar, on the other hand, is a blend: a ready-made surfactant, fatty ingredients that harden it and make it gentle, and a little water. No lye to handle, no curing for several weeks. Its target pH is slightly acidic, around 5 to 6, whereas soap is alkaline, around 9 to 10.

Equipment

• Digital scales accurate to 0.1 g
• A heat-resistant stainless steel or glass bowl, with a lid
• A saucepan for the bain-marie, a kitchen thermometer
• A stainless steel or silicone spatula
• A silicone soap mould, or a pastry cutter
• Safety goggles, gloves, and an FFP2 mask if your SCI is a fine powder
• pH test strips
• A 50% citric acid solution (equal weights of acid and water), in case the pH is too high

Ingredients

For a bar of about 90 g after drying:

These quantities, given as a guide, follow our workshop rule: never less than 25.5% fatty ingredients (stearic acid, oil and cetyl alcohol), here 25.5 g out of 98 g. Essential oils are not recommended for pregnant women and young children: for them, or for an unscented bar, leave them out.

How to make it, step by step

1. Heat the water. Pour the water into the bowl, over a bain-marie, and bring it to around 85 °C. Do not go above 90 °C. Keep your gloves and goggles on: at this temperature, a splash will burn
2. Dissolve the SCI first. Add it gently, without raising dust, in three or four batches, stirring, with the lid on between additions to limit evaporation. Allow 10 to 15 minutes: the paste must become smooth and even, with no grains. Do not move on until it is
3. Add the fatty ingredients. Stearic acid, cetyl alcohol and olive oil, then stir until they have melted
4. Add the glycerine and stir
5. Add the decyl glucoside last, slowly, stirring gently so the paste does not foam
6. Check the pH. Take 1 g of paste, dissolve it in 9 g of lukewarm water and test with a strip. Aim for 5 to 6. If it is higher, add a few drops of citric acid solution, stir and test again
7. Add fragrance. Off the heat, at around 75 °C, add the essential oil
8. Pour straight away. The paste sets quickly: press it into the mould with the spatula
9. Unmould after 24 h, then leave to dry in the open air for 2 to 3 days before your first wash

Mistakes to avoid

• Putting all the ingredients in the bowl at once: the SCI will no longer dissolve and the bar stays grainy
• Adding the decyl glucoside too early: it foams and the paste fills with bubbles
• Heating above 90 °C: the water evaporates and the paste hardens before it can be poured
• Going below 25.5% fatty ingredients
• Leaving the shampoo bar sitting in a puddle of water: it melts, so keep it on a draining soap dish

How to use it

Wet your hair, rub the bar directly onto the wet lengths or work up a lather between your hands, massage your scalp, then rinse. Between uses, let it dry in the open air.

Good to know

SCI powder irritates the eyes and airways: pour it gently, wearing goggles and a mask. This shampoo is for your personal use. To sell it, cosmetics regulations require a product information file, a safety assessment by a qualified professional and a notification before it is placed on the market.

Frequently asked questions

What is SCI?

SCI (sodium cocoyl isethionate) is a mild surfactant made from coconut oil fatty acids. It is not a sulphate. It comes as a powder, flakes or noodles, and it is what makes the shampoo lather.

Why is my shampoo bar grainy?

The SCI was not fully dissolved before the other ingredients were added. Dissolve it first in the hot water, with the lid on, and only move on once the paste is smooth.

Can I use Aleppo oil instead of olive oil?

Yes, at the same weight, 5 g. Aleppo oil, a blend of olive oil and laurel berry oil, adds a subtle note of laurel.

How do you make a shampoo bar lather?

Wet your hair and the bar thoroughly, then rub the bar between your hands or directly onto the lengths. On hair loaded with styling products, the lather builds poorly on the first wash: shampoo a second time.

How long does a shampoo bar last?

Dried properly between uses, on a soap dish that lets the water drain away, a 90 g bar lasts several weeks. How long depends mainly on the length of your hair and how often you wash it.

How should I store it?

Once dry, the bar contains little water, but a homemade recipe has no preservative and no laboratory testing. Work with clean utensils, make small quantities and keep the bar somewhere dry, on a draining soap dish.

Want to try one before you start?

Our olive oil shampoo bar is made in France with an SCI base. And to take homemade further: how to make Aleppo soap.