A Beginner’s Guide to Castile Soap

Sara WagnerTips, Tricks & TutorialsLeave a Comment

Castile soap is arguably one of the most simultaneously simple and complicated soaps in existence! From debates on its origin, to arguments about what it should and should not contain, castile soap means something different to just about every soap maker.

The Debatable History of Castile Soap 

It is difficult to find a definitive answer as to where castile soap originated. Some say that it dates back to Levant, where Aleppo soap makers historically and presently produce hard soaps based on olive and laurel oils. Others say that the soap originated in Castilla, Spain. Whatever the true root of castile soap may be, one thing is for certain; soap makers have been utilizing the benefits of this hard, luxurious soap for thousands of years.

Contents in Flux 

Finding the definitive answer of exactly what castile soap should contain was no easier than learning its history! Some believe that true castile soap is made using 100% extra virgin olive oil and sodium or potassium hydroxide. Others believe that the scope of ingredients encompasses all soaps made with only vegetable derived oils and lye, as long as the recipe is devoid of any and all animal tallow (also known as animal fat). Because of this, it is possible to see a castile soap made from almost any vegetable based oil; but many soap makers still believe that a true castile soap should contain only olive oil as its main ingredient.

The Benefits of Castile 

Finding the benefits of castile soap was easy; this beloved soap is revered for its multi-purpose cleaning skills. In liquid form, many people use it to clean their floors, toilets, sinks, countertops or as a spray-able solution for plants to help repel pests. In bar (and liquid form), castile soap is used to wash the body, hair and face. It is a truly versatile product that is very simple to formulate, and has the added benefit of being vegan-friendly by nature because of its all-vegetable based oil ingredients. Because of its simple formulation, it is also customizable with colors, scents and oils, which means the options for making your own standout soap are limitless.

The Drawbacks of Castile 

Although there are few drawbacks of castile soap, it is important to take them into consideration before making it.

Castile soap can be made using either the cold process method or the hot process method. The biggest difference in these two processes when it comes to castile soap is most definitely the cure time. Cold process castile can take between 4-6 months to cure, with unmolding after a two week initial wait. This can be a big drawback for soapmakers who intend to offer this at an upcoming show or event; make sure to give yourself plenty of time. As with any soap, a longer cure time is desired to produce a harder bar, but this is a must with castile soap.

Using the hot process method will drastically cut down on the cure time, but will not produce as smooth a finished product as cold process. However, the cure time for castile soap using hot process is only about two to four weeks, with unmolding after 24 hours. Although this is a faster turnaround for this particular kind of soap, it is important to note that the longer the cure time, the better your bar will be.

Formulating Your Castile 

Formulation of your castile soap is going to depend on a few factors.

  • Are you making liquid castile, or bar castile? If you are making liquid castile, you will need to use potassium hydroxide. If you are making a bar castile, you’ll need sodium hydroxide.
  • Will you be sticking with the traditional 100% olive oil method, or mixing a few vegetable-only oils?
  • Are you using hot process or cold process, and what is your timeline for a finished product?
  • What will your superfat percentage be? Although superfatting between 5% and 10% is standard, consider reducing your superfat to 3 or 4 percent instead. A lower superfat percentage will help your bar become harder in a shorter amount of cure time.

Final Thoughts 

Castile soap is a simple, traditional product that appeals to a wide consumer base. If you plan around the cure time needed to have a quality, hardened bar, your customers will come back time and again for this amazing soap!



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