What is castile soap — and what can you use it for?
If you've been exploring natural cleaning and personal care products, you've almost certainly come across castile soap. It's one of those ingredients that keeps appearing on "natural home" lists — and for good reason. But what actually is it, and does it live up to the hype?
What is castile soap?
Castile soap is a pure, plant-based liquid or bar soap made from vegetable oils — traditionally olive oil, though modern versions often include coconut, hemp, or jojoba oil for different properties. The name comes from the Castile region of Spain, where olive oil-based soaps were made for centuries.
What makes castile soap different from conventional soap is what it doesn't contain: no synthetic detergents, no sulphates, no parabens, no petroleum-derived ingredients, and no artificial fragrance. It's one of the simplest, most natural soap formulations you can use.
How is castile soap made?
Castile soap is made through a process called saponification — combining plant oils with an alkali (traditionally lye) to create soap and glycerin. The lye is fully consumed in the reaction, so the finished soap contains no lye. What remains is a gentle, effective cleanser with natural moisturising properties from the glycerin produced during the process.
Handmade castile soap, made in small batches, retains more of this natural glycerin than commercially produced soap — which is one reason it tends to be gentler and more nourishing on skin.
What can you use castile soap for?
This is where castile soap really earns its reputation. A single bottle can replace a surprising number of products in your home:
Personal care:
- Body wash and hand soap
- Gentle facial cleanser (diluted)
- Shampoo (works best for oily hair types)
- Shaving soap
- Baby wash (unscented, well-diluted)
Household cleaning:
- All-purpose surface cleaner (diluted with water)
- Dish soap
- Fruit and vegetable wash
- Floor cleaner
- Bathroom scrub
Laundry and more:
- Gentle laundry detergent (small amounts)
- Pet wash
- Plant spray (diluted, helps deter pests)
The key with castile soap is dilution — it's concentrated, so a little goes a long way.
A note on mixing castile soap
One thing worth knowing: castile soap doesn't play well with acidic ingredients like vinegar or lemon juice. Mixing them causes the soap to "unsaponify" — it turns white and clumpy and loses its cleaning power. Use them separately, not together.
Why choose handmade castile soap?
Mass-produced liquid soaps — even those marketed as "natural" — often contain synthetic thickeners, preservatives, and detergents that aren't in true castile soap. Handmade castile soap, made in small batches from quality plant oils, is as close to the original as you can get.
Our castile soap is handmade in New Zealand using plant-based ingredients, with no synthetic additives. It's gentle enough for the whole family — and versatile enough to earn a permanent spot in your home. 🌿