pediaOlive oil is a vegetable oil obtained through mechanical methods (cold press/centrifuge) from the fruits of the Olea europaea L. tree (Oleaceae family) and is a symbol of Mediterranean civilization. Olive oil, the oldest raw material in the history of soapmaking, is the primary component of Babylonian soaps dating back to 2800 BCE. Its high oleic acid content (55–83%) gives soap a unique moisturizing effect and a soft, smooth feel. Castile soap—a pure soap made from 100% olive oil—is the most iconic product in the history of soapmaking.
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Botanical Source and History
Olea europaea L., with a cultivation history spanning over 6,000 years, is the most characteristic tree of the Mediterranean basin. Turkey ranks among the top five olive-producing countries in the world—the Aegean Region (Ayvalık, Edremit, Milas) is the primary production center. Beyond being a staple of the Mediterranean diet, olive oil has been used throughout history in soap-making, lighting, medicine, and religious rituals. The use of olive oil in soap-making dates back to 2800 BCE, to the Babylonian civilization.
Castile soap: The 100% olive oil tradition
First produced in the 12th century in the Castile (Castilla) region of Spain, Castile soap is a pure soap made from 100% olive oil. A luxury hygiene product in medieval Europe, Castile soap was exported to the courts of England and France. Marseille soap (Savon de Marseille) is also olive oil-based and represents a similar tradition.
Chemical Profile
Fatty Acid Composition
Olive oil is rich in oleic acid (C18:1), ranging from 55% to 83%. Other fatty acids: palmitic acid 7.5–20%, linoleic acid 3.5–21%, stearic acid 0.5–5%, palmitoleic acid 0.3–3.5%. Oleic acid is the most common monounsaturated fatty acid and is the primary source of its emollient (softening) properties.
Polyphenols and antioxidants
Extra virgin olive oil contains potent polyphenolic antioxidants such as hydroxytyrosol, oleuropein, and oleocanthal. Oleocanthal is a polyphenol reported to exhibit anti-inflammatory activity in in vitro studies. However, the polyphenol content in refined olive oil is significantly reduced, and a substantial portion of these compounds undergoes degradation during the saponification process.
Its Place in the Scientific Literature
Skin barrier and emollient effects
Oleic acid is a natural component of human skin lipids and acts as an emollient to soften the skin. However, a study published by Danby et al. (2013) in *Pediatric Dermatology* reported that pure olive oil increases transepidermal water loss (TEWL) in healthy adult skin and slightly impairs the skin barrier. This finding has led to a reevaluation of the role of pure olive oil in skin care.
Saponified Form vs. Pure Oil
The above finding applies to pure olive oil (leave-on product). Olive oil in its saponified form (sodium olivate) is a chemically distinct compound—oleic acid reacts with NaOH to form sodium oleate. Sodium oleate is a mild soap salt that is gentle on the skin and minimally drying.
Safety Profile
The CIR panel has determined thOlea Europaeae Fruit Oil is safe for cosmetic use. Its 6,000-year history of use supports its safety profile. Rare allergic reactions are possible—cross-reactivity is theoretically possible in individuals with an allergy to olive pollen. Comedogenic potential: Pure olive oil is rated 2/5 on the comedogenic scale—cautious use is recommended for acne-prone skin.
Olive oil in soap making
SAP value and usage rate
The SAP value (NaOH) of olive oil is approximately 0.134. It can be used at a ratio of 20–100% in soap recipes. Castile soap: 100% olive oil. General recipes: 20–40% olive oil + other oils.
Properties it adds to soap
Olive oil imparts moisturizing properties and a silky feel to soap (oleic acid → sodium oleate), a soft, creamy texture, and a fine, dense lather (does not produce large lather—balanced with coconut oil), a long curing period (100% olive oil soap may require 6–12 months of curing), and, due to its high iodine value, carries a risk of DOS (must be balanced with antioxidants).
Castile soap vs. blended soap
100% olive oil Castile soap is very moisturizing but does not lather on its own, hardens very slowly, and may leave a sticky feeling. For this reason, modern recipes balance olive oil with coconut oil (20–25%—for lather), palm oil (15–25%—for hardness), and other oils.
Types of Olive Oil and Soapmaking
Extra virgin olive oil
The highest quality grade—acidity below 0.8%, cold-pressed. Rich in polyphenols. It can be used in soapmaking but is expensive, and it is unclear whether the polyphenols are preserved during saponification. The intense olive scent may affect the soap’s fragrance profile.
Refined olive oil
A neutral oil obtained from extra virgin olive oil through chemical or physical processing. It has a low polyphenol content. It provides a more neutral scent profile in soapmaking.
Pomace olive oil (prina oil)
Obtained by solvent extraction from the residue (pomace) of the olive press. It is the most commonly used and most economical type of olive oil in soapmaking. Its oleic acid content is similar to that of other grades. Its low cost and neutral scent make it a preferred choice in soap recipes.
Turkey’s Olive Oil Heritage
Turkey ranks among the top five countries in the world for olive production. The Aegean Region (Ayvalık, Edremit, Milas, Akhisar) is Turkey’s olive oil capital. In the Turkish soap-making tradition, olive oil is the most fundamental raw material—Antakya olive oil soaps are living examples of this tradition. In Chailea’s recipes, olive oil serves as the base oil in 23 products.
Frequently Asked Questions
Is olive oil soap moisturizing?
Olive oil soap, which is rich in oleic acid, is a type of soap that is less drying to the skin. However, no soap is an active moisturizer—olive oil soap is a soap that “removes less of the skin’s natural moisture while cleansing.”
Why doesn’t Castile soap lather?
Since 100% olive oil soap does not contain lauric acid, it does not produce a large, airy lather. Instead, it produces a small, dense, creamy lather. Mixing it with coconut oil solves the lathering issue.
Which type of olive oil should be used in soap making?
Pomace olive oil (prina oil) is the most commonly used choice in soapmaking—it is low-cost and has a high oleic acid content. Extra virgin olive oil can be used, but it is expensive, and it is uncertain whether the polyphenols are preserved during the saponification process.
The Traditions of Marseille and Aleppo Soap
There are two major traditions of olive oil-based soapmaking: Marseille soap (Savon de Marseille—France, a 17th-century edict mandated a 72% vegetable oil content) and Aleppo soap (Aleppo soap—Syria, a continuation of the world’s oldest soap-making tradition, made with olive oil and laurel fruit oil). Both traditions reflect the central role of olive oil in soapmaking.
Chailea products containing this ingredient
Olive oil (Olea Europaea Fruit Oil) is the primary base oil in 23 Chailea products, providing moisturization and a soft feel. View all products →
References
1. Danby, S. G., et al. (2013). Effect of olive and sunflower seed oil on the adult skin barrier. Pediatric Dermatology, 30(1), 42-50. doi:10.1111/j.1525-1470.2012.01865.x
2.CIRs Expert Panel. Safety Assessment of Olea Europaea-derived ingredients.
3. Vossen, P. (2007). Olive oil: History, production, and characteristics. HortScience, 42(5), 1093-1100.