Olive Oil Soap Recipe – Cold Process



How to make cold process olive oil soap?

In this article, I will talk about how make homemade olive oil soap recipe cold process. Pure soap has 3 main ingredients: oil, water, sodium hydroxide (caustic). Among these 3 ingredients, sodium hydroxide also known as caustic is a dangerous chemical. So, before starting to make soap, we need to take safety precautions.


What you need for safety:

What you need for safety
Safety tools for soap making
  • Well-fit plastic gloves
  • Protective goggles
  • Remote heat measurement device
  • Sensitive scale up to 1gr
  • Dense plastic strainer
Never try to make soap without using these tools.

Important notes for safety:

  • You should never use any kitchen utensils while making soap and avoid any contact with food.
  • You need to make soap in an environment where you can easily ventilate.
  • During soap making, please keep children away.
  • You need to mix water and caustic for soap making and avoid inhaling the gas in this process.
  • You should always wear your goggles and gloves until you close the soap mould and let it rest.

Utensils for soap making:

Utensils for soap making
  • Plastic cups
  • Plastic spoons
  • Soap mould
  • Hand blender
  • Old cloths
  • Old newspaper

Step by step soap making:

After taking safety precautions, we will prepare your soap. This is what we will do:

  1. Prepare all ingredients and utensils.
  2. Cover your countertop, table with newspaper to avoid any spilling.
  3. Plug the hand blender.
  4. Wear your gloves and goggles.
  5. Add the oil in a bowl and weight.
  6. Add water to a bowl and weight.
  7. Caustic in another bowl and weight
After having the caustic you need, keep caustic in dry and dark area. When caustic contacts air, it will lose its soap making property.

After preparation step, we will begin with the most important stage. Let’s make our soap.

Cold process olive oil soap preparation (8% oil):

Olive Oil Soap Ingredients

  • 1kg olive oil (while making cold process soap, we cannot use low quality and old oil. Bad oil will only make the soap go bad.)
  • 300 gr water (water ratio should never be more than one third of total oil ratio and it should be at least 2 times more than caustic ratio)
  • 124 gr caustic

Each oil has specific saponification coefficient. This coefficient shows necessary caustic amount for saponification. Saponification coefficient of olive oil is 0.1345. This means, if you want to completely saponify olive oil, you need to add 134.5 caustic for 1kg olive oil.


If you want your soap to have moisturising effect in addition to cleaning effect, you need to make sure that certain amount of oil is not saponified. You need calculate and decrease caustic ratio.

In this recipe, our ratio is 8%. this means, in 1000 gr olive oil, 80 gr stays as oil without saponification. So, we need to decrease caustic ratio as 8% or 10.76 gr.

Saponification coefficient is different for each oil. As the oil ratio in soaps increase, they will have shorter shelf life. Ideal ratio is 6-8% for hand soaps.

You can also mix multiple oils to make soap. But, you need to carefully weight each oil and calculate caustic amount you need for each oil.

Let’s see how we make our soap:

We add the caustic to water bowl and mix slowly. When we add caustic to water, there will be heat and the temperature will rise.

Also, there will be gas. You should avoid inhaling this gas.

You need to mix caustic for 1-2 minutes with a plastic spoon to mix it with water.

When caustic melts in water, you need to wait for a while to cool down the mixture. The temperature you need is 30-40 and you may need to wait for 2 hours during summer. Securely position caustic mixture while waiting and make sure that this mixture will not spill.

Measure the temperature of the bowl remotely. When it is between 30-40 degrees, we slowly pour this caustic water from plastic strainer.

Straining is necessary to eliminate any remaining caustic pieces in the mixture and avoid any danger.

We start mixing step. We can only mix this mixture with plastic spoon. But since this takes too long, we can use hand blender. We are mixing the ingredients with hand blender and obtain pudding like consistency.

When the mixture has pudding consistency, it can solidify in short time and lose the fluid structure. So, we need to mix all ingredients before solidification.

We pour this mixture to soap mould and cover it with old cloths.

Soap bar
Soap bar olive oil soap recipe

The purpose for this is to ease gelling of the soap mould. Soap mixture will heat and become fluid in the mould and this is called gelling. This gelling will speed up saponification. You cannot observe this gelling in single soap moulds, so it will take longer to make a soap.

Soap bar
Soap bar – olive oil cold process

After waiting at least for 24 hours, we take our soap out of the mould and cut it as we like.

If we remove the soap early, we can see a white powder called incineration. This will not affect the quality of the soap but it will affect how the soap looks.
Olive oil soap
Homemade olive oil soap

Cutting and storage:

After cutting our soap, we are placing the soap to on paper towel in an airy environment without direct sunlight and wait for up to 6 weeks.

soap cutting tool
Soap cutting tool
Our first purpose for this waiting is to decrease pH level. When the soap is fresh, pH level is higher and this will dry the skin. pH level will decrease over time to desired level. Another purpose is that the water in the soap will evaporate and the soap will become harder. This will prevent the soap to be smudged and finish quickly.

After all these steps, if the soap will be packaged, packages should enable air circulations. Paper packages are suitable for this purpose.