Make soap with olive oil

There is a profound, quiet magic that happens when you combine simple kitchen oil with an alkali solution to create something as essential as soap. My love affair with olive oil soap began in my tiny kitchen over a decade ago, seeking a gentle, unscented remedy for my daughter’s incredibly sensitive skin.

My Journey with Castile Soap

I still remember my very first batch of pure olive oil soap, often called Castile soap. I had read every book I could find, yet I was shaking as I donned my rubber gloves and safety goggles. I treated the lye solution like it was radioactive material, moving with exaggerated slowness across my countertops.

That first batch was a lesson in humility and patience. I didn’t realize that 100% olive oil takes significantly longer to reach “trace”—the point where the oil and lye emulsify—than other oil blends. I stirred by hand for nearly an hour, wondering if I had broken the laws of chemistry.

Soap making is the perfect marriage of strict chemistry and artistic expression; it demands respect for the process but rewards you with infinite creativity.

When I finally poured it, I was elated, but my impatience got the better of me. I tried to use a bar after only four weeks of curing. It was slimy, gelatinous, and dissolved rapidly in the shower. It wasn’t until I let the remaining bars sit for a full six months that I discovered the hard, white, mild soap I had been dreaming of.

What This Craft Really Entails

Making soap with olive oil is a specific subset of the “Cold Process” soap-making technique. Historically rooting back to the Castile region of Spain, this craft relies on the chemical reaction called saponification. Unlike “Melt and Pour” bases where the soap is already made, here you are the chemist creating the surfactant from scratch.

Lisa Mandel

This craft is not for those who need instant gratification. While the active work might only take an hour, the maturation process is akin to aging a fine cheese or wine. You are transforming liquid fat into a solid crystal lattice structure.

Have you ever wondered why handmade soap feels so much creamier than store-bought bars? It is because commercial manufacturers often remove the natural glycerin—a byproduct of saponification—to sell it separately in lotions. In our craft, that humectant stays right in the bar, drawing moisture to your skin.

True Castile soap is technically made from 100% olive oil, though modern variations often include small amounts of coconut or castor oil to increase lather.

This pursuit is best suited for intermediate crafters or patient beginners who are willing to follow safety protocols strictly. It requires precision; you cannot “eyeball” measurements like you might in cooking. Every gram counts to ensure the soap is safe to use.

Essential Materials and Tools

Key Techniques and Skills

• Lye Solution Preparation: Mixing sodium hydroxide into water in a well-ventilated area to create the caustic solution needed for reaction.
• Temperature Management: bringing both the oil and the lye water to similar temperatures (usually around 100°F-120°F) before combining.
• Stick Blending: Using pulses of an immersion blender to emulsify the mixture without introducing too many air bubbles.
• Identifying Trace: Recognizing when the batter has thickened to the consistency of thin pudding, leaving a trail on the surface when drizzled.
• Insulation: Wrapping the mold in towels to encourage the “gel phase,” which helps colors pop and the bar harden.
• Curing: Storing cut bars in a cool, dry place with airflow to evaporate excess water and complete the crystalline structure.
• Safety Testing: Using pH strips or the “zap test” (for brave souls) after the cure to ensure no active lye remains.
• Beveling: Trimming the sharp edges of the raw soap bars for a professional, comfortable hand-feel.

SAFETY CRITICAL: When mixing your solution, always add the lye crystals to the water, never pour water onto lye crystals, as this can cause a dangerous volcanic eruption.

Skill Level and Time Investment

Advantages and Challenges

The Benefits:

• Gentleness: It is arguably the mildest soap in existence, perfect for babies and those with eczema.
• Cost-Effective: Olive oil is readily available in bulk at grocery stores, making it one of the cheaper oils to source.
• Simplicity: You technically only need three ingredients (oil, water, lye) to make a functional product.
• Longevity: Once properly cured, a bar of Castile soap lasts a very long time in the shower compared to coconut-heavy soaps.
• Creative Control: You decide exactly what touches your skin—no hidden preservatives or sulfates.
• Heritage: There is a deep satisfaction in practicing a craft that has been around for centuries.

The biggest frustration with olive oil soap is the “slime factor.” If used before a long cure, the soap produces a stringy, mucous-like lather that many find unpleasant.

The Challenges:

• Patience Required: The curing time is significantly longer (6-12 months) than standard soaps (4-6 weeks).
• Softness: Unmolding can be difficult; if you try too soon, the soap will be like soft cheese and dent easily.
• Low Lather: Pure olive oil soap does not produce big, fluffy bubbles; it creates a lotion-like cream instead.
• False Trace: It is easy to think the batter is mixed when it isn’t, leading to oil separation in the mold.

Real Project Applications

One of the most rewarding projects I ever undertook was making “Year One” baby soap for my niece. I made the batch two months before she was born so it would have a solid cure by the time she arrived. I used a simple silicone loaf mold and poured the pale, creamy batter in without any colorants or scents.

The result was a set of ten substantial bars that were white as bone and smooth as polished river stones. I wrapped them in breathable cigar bands made of craft paper. My sister used them for everything from washing the baby to hand-washing delicate onesies. It was a practical gift that carried love in every sud.

Another excellent application is facial bars. Because olive oil soap is non-stripping, I make small, round guest-sized bars specifically for facial cleansing. I often infuse the olive oil with chamomile or calendula flowers for six weeks before starting the soap-making process.

Why spend a fortune on high-end cleansers when your kitchen can produce something superior? These small facial bars make incredible wedding favors or holiday stocking stuffers. They look elegant, smell faintly of clean oil and soap, and actually improve with age on the shelf.

The Learning Experience

Learning to make soap is like learning to drive; at first, you are hyper-aware of every danger, gripping the wheel tight. Over time, it becomes muscle memory. My early mistake was constantly checking the soap while it was in the mold.

Do not succumb to the temptation of peeking under the towels or poking the soap while it is saponifying; rapid cooling can cause “soda ash,” a harmless but ugly white powder, to form on top.

I found that joining local soap-making guilds and online forums was invaluable. The community is incredibly generous with troubleshooting. If your soap cracks, someone knows why (it got too hot). If it smells like rancid crayons, someone knows why (old oil).

My breakthrough moment came when I started using a specialized “soap calculator” online. Before that, I was relying on book recipes that were sometimes inaccurate. Understanding that I could tweak the water-to-lye ratio to control how fast the soap hardened was a game-changer for my confidence.

Comparison with Similar Crafts

Common Questions from Fellow Crafters

Q: Can I use the olive oil from my pantry?

A: Yes! In fact, many soapers prefer the cheaper “Pomace” olive oil over Extra Virgin because it traces faster and makes a harder bar, though it may result in a greener color initially.

Q: Is lye really that dangerous?

A: It demands respect, not fear. It is a caustic chemical that can cause blindness or burns, so goggles and gloves are non-negotiable. However, once saponification is complete, no lye remains in the final product.

Q: Why did my soap turn into a weird, separated mess in the mold?

A: This is likely “false trace.” You stopped mixing because it looked thick, but the oil and lye weren’t fully bonded. With olive oil, you must mix until it truly resembles a stable pudding.

Q: Can I add essential oils?

A: Absolutely. Lavender and lemongrass work beautifully. Just be aware that some florals can accelerate the thickening process, forcing you to work very quickly.

Q: How do I know when it’s safe to use?

A: Technically, saponification is done after about 48 hours. However, using the soap before a 6-month cure results in a slimy, soft bar that dissolves instantly.

Q: My soap has a white powdery film on top. Is it ruined?

A: Not at all! That is soda ash, caused by the air reacting with the raw soap. You can steam it off or simply wash it off the first time you use the bar.

Pro Tip: Adding a teaspoon of sodium lactate (a liquid salt derived from fermentation) per pound of oils to your cooled lye water will help the soap harden significantly faster in the mold.

My Personal Results and Insights

Final Thoughts and My Recommendation

Making soap with olive oil is a practice that slows down time. In a world that demands speed, there is something deeply grounding about making a product today that you won’t use until next year. It forces you to plan ahead and trust the process.

I highly recommend this craft for anyone who loves cooking, baking, or chemistry. It is not the best starting point if you are looking for a weekend craft to gift on Monday—try Melt and Pour for that. But if you want to create a luxury product that is genuinely better than anything you can buy in a drugstore, this is it.

There is no feeling quite like stepping into a shower with a bar of soap you made from scratch, knowing exactly every atom that went into it.

The initial investment in safety gear and a stick blender is modest, and the ongoing cost of materials is low. The real cost is space for curing and the discipline to wait. Precision in weighing ingredients is the secret to success, so get a good scale and trust your numbers. If you have the patience, the result is a creamy, luxurious Castile soap that is worth every minute of the wait.