Choosing the right oils for soap making can feel overwhelming—especially when you’re just starting out. Should you use olive oil or coconut oil? What does castor oil actually do in a soap bar? And how do you get that perfect mix of bubbles, moisture, and hardness?
Soap making is both an art and a science, and oils are at the heart of it. Each oil brings unique properties that affect how your soap behaves—from its lather to how long it lasts in the shower. Whether you’re formulating your first bar or refining a signature recipe, understanding the characteristics of popular soap making oils will give you full control over your finished product.
Let’s break down the best oils for soap making and what each one brings to the table.
Olive Oil: Gentle and Moisturizing
Olive oil is a classic soap making staple. Known for its moisturizing properties, olive oil creates a mild, gentle bar that’s great for sensitive skin. It produces a low, creamy lather and is often used in recipes for baby soap, facial bars, and Castile soap.
The downside? Bars made with 100% olive oil can take longer to cure and may feel slimy if not balanced with other oils. That’s why many soap makers blend it with harder oils for better results.
Coconut Oil: Cleansing and Lather Boosting
Coconut oil is a powerhouse in soap making. It produces a hard bar with big, fluffy lather and excellent cleansing ability. It’s great for removing dirt and oil—but too much can be drying to the skin.
Most soap makers limit coconut oil to around 20–30% of their recipe to balance its strong cleansing power with more moisturizing oils like olive or avocado oil.
Palm Oil: Hardness and Creamy Lather
Palm oil gives soap a firm, long-lasting structure and contributes to a stable, creamy lather. It’s commonly used to help balance softer oils like olive and sunflower.
However, palm oil has sustainability concerns. If you choose to use it, look for RSPO-certified (sustainably sourced) palm oil to ensure ethical production practices.
Castor Oil: Lather Stabilizer
Castor oil is a liquid oil that adds great lathering qualities. It doesn’t create bubbles on its own but helps boost and stabilize the lather created by other oils like coconut or palm.
It’s typically used in small amounts—around 5–10%—but makes a noticeable difference in the final soap bar. It also adds a slightly silky feel to the lather, which many users love.
Avocado Oil: Rich in Nutrients
Avocado oil is a luxurious oil high in vitamins A, D, and E, making it ideal for nourishing and conditioning the skin. It produces a gentle, conditioning bar and can be used up to 20% in soap recipes.
Its creamy lather and moisturizing properties make it a favorite for facial soaps or cold-weather bars when skin needs extra hydration.
Shea Butter: Creamy and Conditioning
Shea butter is a solid fat that’s great for creating a hard bar with a creamy, moisturizing lather. It adds richness and conditioning properties, making it popular in body bars, facial bars, and luxury soaps.
Typically used at 5–15%, shea butter blends well with other oils and helps make a more nourishing final product.
Sunflower and Canola Oil: Budget-Friendly Additions
Sunflower and canola oils are inexpensive, high-linoleic oils that can soften soap and increase moisture content. However, they can speed up oxidation and shorten shelf life, so they’re often used in small amounts (around 10–15%) and paired with antioxidants like Vitamin E or rosemary extract.
Conclusion
The best oils for soap making depend on what kind of soap you want to create. If you’re after a bubbly bar that lasts long, coconut and palm oil are a great base. For something gentler and moisturizing, olive and avocado oils are ideal. And if you want to enhance lather, don’t forget castor oil—even a little goes a long way.
Blending oils lets you customize your soap’s feel, performance, and skincare benefits. With practice, you’ll develop your own favorite oil combinations—and maybe even your signature bar!