how to make castile soap
as simple as 1-2-3!

This page will explain how to make castile soap. Castile soap is a term that might be used loosely and mean different things to different people. The name Castile comes from the region in Spain where this type of soap originated from.

Certain soap makers will use other oils such as coconut oil, shortening or palm oil to add some hardness and bubble to the bar and reduce the cure time. Some call these recipes bastile soaps. I have recipes using 80% olive oil here.

For our purpose of learning how to make castile soap, we will keep it very simple (3 ingredients) and make a castile soap using 100% olive oil (the one at the supermarket), distilled water and sodium hydroxide, also known as lye (you will need to purchase the lye from a supplier or a hardware store).

Castile 100% Olive Oil


Fats, oils and butters

  • 600 grams olive oil

Lye ― Water Solution

  • 77 grams lye (sodium hydroxide)
  • 228 grams distilled water

This recipe makes over 2 pounds of soap which will produce about 6-7 bars of natural soap.

Get your soap making equipment ready. Prepare your workspace, I like to cover my area with plastic and make sure that you are using safety gear. You will need goggles, gloves and long sleeves is a good idea. I also wear a mask to prevent when I am mixing my lye solution.

This is a cold process soap making recipe but to keep this simple I use the room temperature method.

Weight out your ingredients.

Slowly add the lye to the water and gently mix using a spatula. Dissolve all the crystals in the water making sure that there is no undissolved lye.This step I always do in a sink or a roasting pan for safety measures.

Once it is clear you can slowly pour into into your olive oil.

You will need a You really need a stick blender for this recipe, a whip of spoon just won't make it happen.

Using a stick blender mix until you reach trace. This is when your mixture is thick enough that when you drizzle some on the top of the mixture, it leaves a trail on top. This is a castile soap so it will probably take longer than other recipes, plan 10 to 15 minutes.

When you reach trace you would then add any fragrance (essential oils or fragrance oils) and color if you wish. To ensure that the scent last I would use about 15 grams per 454 grams, so about half an ounce per pound of oils.

This castile soap is a wonderful baby soap that I will leave unscented. I will also be using this as a base for some baby laundry soap.

Pour into your soap mold and then spray with alcohol to prevent ash a few times in the next hour. Cover with plastic wrap and insulate with an old towel.

Let sit for 3 to 4 days then unmold and cut. You know know how to make castile soap.

Leave to cure for 4 to 6 months and enjoy this fabulous healthy homemade castile soap.If you are interested in enjoying your soaps earlier you might consider making olive oil castile soap using the hot process method.

Find more information about cold process soap making and here are more recipes you can try.

Want to learn how to make castile soap using the hot process soap making method, go here.

You want a nice twist to castile soap, check out this castile buttermilk recipe with infused oil to add a light fragrance naturally.

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Find more castile soap recipes

Learn how to make castile soap using the hot process method