Castile Soap Recipe

A Castile Soap Recipe includes making soap with 100% Olive Oil or using a majority of olive oil as the main ingredient in the soap.

Original soaps were made from animal fats and alkali ashes.  Castile soap was discovered in Europe around the 12th century AD. 

It was a new concept to make soap from plant-based oils instead of animal fats.  The Castile Soap was known to be significantly milder than soaps made from animal fats.

Castile Soap Recipe:

1. OILS. To make this castile soap we will combine Olive Oil and Coconut Oil.  Included are the percentage amounts of each oil and weight in ounces.

a. Olive Oil- - - - - -85%……17.0 oz.

b. Coconut Oil- - - -15%……..3.0 oz.

Total of 2 Oils   =   100%  =  20.0 oz.

2. LYE AMOUNT = 2.69 oz. (5% Superfatting)

3. H20 AMOUNT = 6.62 oz.


a. Lavender Essential Oil (2 % of total oil amount). Amount added at trace = 0.4 oz.

Castile Soap by the numbers

The Castile Soap Recipe uses 2 oils. They are Olive Oil and Coconut Oil. From these two oils we can calculate our soap attribute numbers from the Soap-Calc.

1. Hardness of ( 26 ).

2. Cleansing Capabilities at ( 10 ).

3. Conditioning Qualities are at ( 71 ).

4. Bubbly number is ( 10 ).

5. Creamy number is ( 16 ).

6. Iodine is at ( 74 ).

7. The INS number is at ( 128 ).

So what do all these numbers mean? Well, with these numbers we can compare our soap recipe numbers with the optimal range numbers from the Soap-Calc.

Compare your Castile Soap Recipe to range numbers

So here’s how our soap recipe fits into each of the ranges.

1 Hardness. Best range is between (29 – 54). The higher the number the harder the soap bar. Our hardness number was ( 26 ) which is below the range. This will be a very soft soap.

2. Cleansing. Best range is between (12 – 22). The lower the number the more mild the soap. Our cleansing number is ( 10 ) which is off the chart for mild! This will be a mild soap.

3. Conditioning. Best range is between (44 – 69). The higher the number, the more soothing and softening to your skin. Our number is ( 71 ) which is above the range. This bar of soap will be very soothing and softening to the skin.

4. Bubbly. Best range is between (14 – 46). Higher numbers in this category equate to more bubbly lather. Our Bubbly number is ( 10 ). This is out of range in the bubbly category. This means that this soap bar will have very little bubbly lather.  

5. Creamy. The best range is between (16 – 48). The higher the number the more lather you will have. Our Creamy number is ( 16 ) which means this soap will have the normal amount of creamy lather.

6. Iodine. The range here is anything (under 70). If your number is below “70” the soap will not go rancid. Our number is ( 74 ) which means this soap could go rancid.

7. INS. The best range here is between (136 – 165). The lower the number the more moisturizing the soap will be to your skin. We have the number ( 128 ). This is below range. This soap will be highly moisturizing to the skin.