Making natural soap from scratch

While I have been posting on some elaborate methods like liquid or transparent soapmaking, I did not cover the basics!

Making natural soap from scratch (means from lye and oils) is more elaborate than just melt&pour or rebatching (see my post on How to make soap – 3 basic methods)

But, it is also a lot of fun! 🙂

I really like to compare it to baking or patisserie – while there are some basic ingredients (flour, eggs, sugar, milk…), there are still hundreds of options for tweaking and creating cakes of different colors, tastes, forms and structure.

However, before going all special and funky, we need to learn the basics! – and the same applies for soap…

…therefore, in a series of posts I am going to explain you the important basics of making natural soap from scratch.

I will not just repeat what was said hundreds time before. I am going to add my own experience and knowledge and am really looking forward to it.

Let’s start, I will keep it simple for today!

After reading this first part, you will know:

  • the ingredients you really need for making natural soap
  • what are the basic steps of making natural soap (soapmaking)
  • a bit on how the basic ingredients affect soapmaking process and the final soap
  • basic methods of soapmaking from scratch

If you are new to soapmaking from scratch, you might want and need to read this article multiple times. That is alright, do it, it is really important!

Basic ingredients

Please, read first my post on what is soap from a chemical point of view. This is important so that you can understand all the following.





Read it? Great, now, you will understand that the only ingredients you really need are (…drums…)


Lye, oils and water – everything else is optional!

Very simplified explanation:

Lye is a base, which reacts with oils (acid) and create soap. Water is needed, otherwise nothing would happen.

Indeed, other types of bases can be used, but these either won’t create a good soap (Ca2OH gives unsolvable soap) or would take many hours of boiling (the carbonates of potassium/sodium from plant ashes)

Hint: Mineral oil has a different chemical structure and won’t create soap.

So you cannot really make soap from your old car oil… 🙂


Let’s see these ingredients in more detail:

  • Lye


Either sodium hydroxide (NaOH, caustic soda) or potassium hydroxide (KOH, caustic potash)

Lye is turning oils and fats into soap. If you measure it right, there is no lye left in your final soap. You do not want any lye left in your soap, because it is caustic – it reacts with your skin and burns it. But the amount of lye is very easy to calculate, you will learn it later.

Not sure where to find it in your country? See my blog post Where to find caustic soda all around the worldCaustic-soda-france

  • Fats/oils

Plant or animal

Different oils and fats make different soaps. Coconut oil makes hard soap with lot of suds and big bubbles, olive oil makes soap that gets slimy when used and has no lather, however is very mild to your skin. All this because of different types of fatty acids oils and fats contain. You will learn about this later, too.

  • Water

Lye could never react with fats or oils if there was no water. Water helps the molecules of NaOH to dissolve into Na+ and OH- ions and bring them to oil molecules to make soap. You need to add just the right amount of water. Too little or too much will slow down or even stop the reaction.


Basic steps


This is a nice thick trace

… here is a very brief description of the soapmaking process:

1. Dissolve your (potassium or sodium) hydroxide in water – thus you prepare your lye solution

2. Pour your lye solution into the fats/oils

3. Stir and blend until an emulsion (the mix gets whiter and thicker, pretty much like when you make mayonnaise) – called trace (see image on right)

4. Add optional ingredients (color, fragrance,…)

5. Pour your soap into molds

6. After 12-48 hours, unmold and cut if needed

7. Let the soap “cure” for 2-3 weeks (it gets milder over time, evaporates water, gets harder)

Basic methods

There are two main methods for making soap from scratch: cold process and hot process soapmaking.

The above described in basic steps is the cold process. The hot process differs in step 2 – after trace, the pot is put on the double boiler, so that the temperature of soap keeps at around 60-70°C for around 1-2 hours. This accelerates the saponification and soap changes into semi-transparent, thick mass, that has to be spooned into molds.


Hot process soap

This is hot process soap after 2 hours in the pot

I discuss the main differences between these two methods in my post Cold process vs hot process, which method to choose?

Indeed, there is quite an impressive quantity of other methods, which are basically variations of these two methods. In some, the soap is first poured into silicone or wooden molds and only then put in the oven to warm soap as in the hot process. This is called cold process owen process (CPOP) method.

In others, soap is whipped instead of blended and a whipped soap floating on the water is born.

Using partly KOH and partly NaOH, solid oils (fats) together with whipping gives a cream soap.

Transparent soapmaking is a variant of hot process technique, when after the soap is finished, it is dissolved in a mix of glycerine, alcohol and sugar solution to achieve transparency.

Using KOH instead of NaOH in the hot process gives a paste that can be later easily dissolved in water to obtain liquid soap.


See you in one of my next posts for more info on soapmaking basics!