The classic soap oil
Olive oil has been used to make soap for a very long time, and traditional soaps from the Mediterranean region are built around it. Today it remains one of the most popular oils among hobby makers, largely because it is easy to find, reasonably priced in many places, and makes a mild bar.
What makes olive oil soap gentle
Olive oil is rich in oleic acid, a fatty acid that makes a soap that is mild and conditioning in feel. Compared with bars built around coconut oil, an olive soap tends to be less aggressively cleansing. The lather is typically smooth, creamy and lotion-like, with small, dense bubbles rather than big airy ones.
For people who find stronger soaps drying, olive-based bars are often a comfortable choice. Individual skin differs, so no oil suits everyone, and persistent dryness, redness or itching is a good reason to talk to a health professional. A related read is the discussion of the benefits of handmade soap for sensitive skin. Some people with sensitivities do well with simple, short-ingredient bars, while others still react, so patch-testing is sensible.
Trace: slow and forgiving
Trace is the point at which the batter thickens enough to leave a faint trail on the surface. Olive oil is known for taking a long time to get there. In a high-olive recipe, a maker may stick-blend for much longer than they would with a recipe heavy in coconut or palm.
This slow trace has a useful side. It gives time to add colors, pour layers and make swirls without the batter thickening in the pot. Beginners often like it for exactly this reason. The same quality can be a nuisance if you are short on patience, and some makers use stick blending in short bursts to avoid overheating a motor.
Soft bars and the long cure
A soap made entirely or mostly from olive oil is soft when first made. It may take several days, sometimes longer, before it can be unmolded and cut cleanly. Even after cutting, it benefits from an extended cure. Where a typical bar might be ready for use in a few weeks, an olive-dominant bar is often left for much longer, with many makers waiting several months. The reason is that these bars harden and mellow slowly as water evaporates. The subject is developed further under why soap needs a cure time.
Using a bar too early can mean a soft, slimy feeling that wears away quickly in the dish. Mushy soap has several possible causes, but an undercured high-olive bar is a classic one.
Castile and balanced blends
A bar made with essentially only olive oil is called castile soap. It is mild and prized by purists, but it can have a thin, slick lather and takes a long time to cure. Many makers prefer a balanced recipe, with olive as the main oil and a smaller share of firmer or bubblier fats added.
- A hard oil or butter helps the bar firm up faster.
- A modest amount of coconut oil improves bubbles.
- A little castor oil supports creamy, longer-lasting lather.
The result is a bar that keeps much of olive oil’s mildness with fewer of its drawbacks. If you want to adjust a recipe, rerun it through a soap calculator, because different oils need different amounts of lye.
Choosing an olive oil for soap
You do not need an expensive, premium oil. Makers commonly use plain, inexpensive olive oil, sometimes labeled pure or light. Extra virgin oils work too, but they are costly, and the soap tends to lose any distinct olive scent. Some makers like pomace olive oil, a lower-grade oil extracted from the pressed remains, though it can behave a bit differently and sometimes produces a greenish tint. Whatever you choose, look for oil that is fresh and smells normal. Old or rancid oil can cause orange spots and an off smell in the finished bar.
A pale green or yellow tint in a bar is normal. The color often lightens over the cure.
Practical cautions
Olive soap is still lye-based soap, so the same precautions apply to every batch.
- Wear protective gear such as goggles and gloves.
- Work in a well-ventilated space.
- Keep children and pets away from the workspace.
- Follow a trusted, tested recipe from a reliable source instead of improvising lye amounts.
Do not assume a slow trace means you can relax. The lye solution is just as caustic, and the bar is not ready to handle freely until it has cured.
Is olive oil right for you?
If you want a gentle bar and do not mind waiting, olive oil is hard to beat as a foundation. If you want a firm, bubbly bar quickly, you may do better to use it as one oil among several. Either way, keep notes and be patient with it.