The History of Castile Soap

This week, my idea for a blog went off on a royal bunny trail when “handmade home products” turned into “what’s Castile soap made out of anyway?” Researching this took me on a journey that spanned almost 500 years, beginning in Syria during the crusades and ended in the royal bathroom. Who’d have thunk? If you think that soap is a relatively new invention, you would be right – and wrong. Before the 18th century (1700s) soap was expensive, so it wasn’t found as a staple in every home. However, evidence of products created by boiling ashes with fat have been found as far back as the ancient Babylonians in 2800 B.C.

 The origins of Castile Soap can be traced back to its predecessor which fell into the hands of crusaders between the years of 1095-1291. The crusaders carried Aleppo soap from the region of Syria back to Europe. In Syria, Aleppo soap was created by combining olive oil, laurel bay oil, lye, and water from locally-sourced materials that were available in the Levant (modern-day TurkeySyria, and Lebanon.) But in Europe, Laurel leaves were hard to come by and people soon had to add their own regional twists to the recipe. By the 12th century, both local soap makers and Muslim emigrants were creating soap from various recipes and qualities throughout the Spanish cities of Carthagene, Malaga, Castile, Alicante and the Italian cities of Genoa, Naples, Bologna and Venice.

History of Castilian Soap

But it was Castilian soap makers who created a soap that outshone all others. First, they would burn halophyte plants (plants that are able to grow in saline conditions) to create ashes. I wondered which plant exactly and it seems that the Salicornia species was commonly used for soap making, so perhaps that? More research is necessary.

Next they would boil those ashes with high-quality olive oil, replacing the popular use of animal fats. (Which they then advertised as cruelty-free and sold to the vegans among them… Just kidding.) To this mixture, they would pour in brine to the boiled liquid and wait for the soap to float to the surface where it could be skimmed off, leaving behind the impurities and excess lye.

This process created what may be considered the first hard, white soap which continued to hold its color as it further hardened with age. Placed next to a green Aleppo soap, it was sure to catch the eye. And it did, rising in the ranks until it served to clean the bodies of Spanish royalty before making its way into royal baths across Europe. By the 1500s, it reached as far as England.

Using Castile Soap Today.

In the past half century, Castile Soap is a term that applies to any soap made from the saponification of vegetable oils and can include other oils like coconut, jojoba, and many others. Essential oils are often added for scents. One of the most popular modern versions was invented during the 1880s by a German family of the name Heilbronner, which was used in washrooms in Germany and made its way to America around the late 1920s. It is used today as an alternative to soaps that include unhealthy, unbiodegradable products such as petrochemicals, and toxic foaming agents, preservatives, and fragrances.

It is an ingredient that is used frequently in a book I spent last evening pouring over by Merissa A. Alink,  who collected recipes to create her own body and household products. The book, Little House Living, has literally a recipe for almost anything you might need in your house from shampoo, to lip balm, to dish soap, and floor cleaner.

To see a handful of Merissa’s recipes that feature Castile Soap, you can read her blog here. Whenever anyone questions your homemade ingredients, just give them a secret smile and say, “Why thank you. I clean everything using a choice ingredient of royalty.”

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