Solid Shampoos: Basic Procedure

[Qui trovate la versione italiana di questo articolo]

Other articles of the Solid Shampoos series:

In this article, I will list the steps that I follow when I produce a solid shampoo. You can follow these steps if you reproduce any of my solid shampoo formulas. If you follow someone else’s formula, please follow their own guidelines!


  • Double boiler (water bath) or hot plate
  • Beakers (at least 3, a big one, a medium-big one, and a small one)
  • Glass rods, spatulas or spoons
  • Scales
  • Dust mask (important!)
  • Lab gloves
  • Soap moulds
  • Optional, if you use SCI in needles form instead of powder: a grinder or a mortar with pestle


  1. Wear protections, especially the dust mask. This is VERY important, since solid surfactants are very dusty and you should not breathe them.
  2. (Optional) Smash the sodium cocoyl isethionate, if it’s not in powder form. I do it with a grinder, it’s possible to do it also with a mortar and pestle if you’re using small amounts.
  3. Prepare A (surfactants): transfer the solid surfactants in the big beaker (in my recipes: sodium cocoyl isethionate and sodium lauryl sulfoacetate). Then add the liquid surfactants (in my formulas: cocamidopropyl betaine and coco glucoside). Mix with a glass rod or a spatula: you will get a sort of paste.
  4. Prepare B (conditioning agents and fats): scale the components of B and transfer them in a medium-big beaker.
  5. Heat A and B. Heat beakers A and B on a water bath or hot plate until the components of B are completely melted. A will not melt, but it’s useful to heat it up such that it’s roughly at the same temperature as B.
  6. Prepare C: meanwhile, prepare the components of C (typically, the preservative).
  7. Mix A and B: when B is melted, add it to A and mix with the glass rod or the spatula to incorporate it.
  8. Add C. Incorporate the component(s) of C to the paste. The pH of the mixture should be already “the right one”, around 5.
  9. Transfer in the soap mould.
  10. Wait. Place the mould in the fridge and wait some hours for it to cool down. After some hours you can remove the shampoo bars from the mould. I suggest to wait a day or two before using them.

Note on formulas that include powders

There are two ways to incorporate powders in the shampoo:

A. Addition of the powders at the end, as D phase. I did this at the beginning, it works but it’s very tough to incorporate them well in the paste.

B. Addition of the powders to B before mixing A and B. That is: scale the powders separately, then as soon as B is melted, add them to B. Mix well to suspend the powders, then proceed with the addition of B to A.


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