Castile Soap (Liquid)
Castile Soap (Liquid)
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I’m sorry to burst any bubbles here (pardon the pun), but you can’t make a true liquid soap by diluting a hard soap bar. A proper liquid soap is made using a specific type of lye that keeps it liquid - and this is exactly that. A pure liquid Castile Soap that’s gentle, versatile, and a staple under my sinks.
Why you’ll use this
Why you’ll use this
This is a 100% pure liquid soap. Not a detergent. Not a soap-lookalike.
“Castile” refers to the region of Castile in Spain, where this style of soap originated centuries ago. Traditionally, it was made with olive oil only. Today, other oils can be included, but to be considered Castile soap, olive oil should make up at least 80% of the base.
Ingredients:
- Olive oil
- Coconut oil
- Filtered rainwaterPotassium hydroxide (lye)
The naturally occurring glycerine is retained.
A note on temperature
Because this soap contains a high percentage of olive oil, it can go cloudy or develop white sediment when temperatures drop below about 15°C.
This is completely normal. As soon as the temperature rises again, the soap clears. There is absolutely nothing wrong with it - I promise.
Good to know
Good to know
Castile Soap is concentrated, so dilution is usually the way to go.
Here’s how I use it at home:
- A small squirt in an amber glass spray bottle topped with water for bathroom cleaning
- The same approach for kitchen surface sprays (great for benches, cooktops and chopping boards)
- One squirt in a foaming pump bottle, topped with water, for instant foaming hand or face wash
- Diluted and thickened with glycerine and xanthan gum to make dish and dog wash
You can use it straight from the bottle if you want, but most uses work best diluted.
Packaging details
Packaging details
Not only is this ingredient beautiful on the inside - it’s just as stunning on the outside, packaged in a premium amber glass, pharmaceutical-grade bottle.

Enjoy 15% Off
When you bundle any 4 ingredients. Discount will be applied at checkout.
Clean on Your Terms
You choose the ingredients, giving you full control over what comes into your home.
One Ingredient. Endless Uses.
No single-use products. Each ingredient works solo or together across many tasks.
Full Green Approach
Biodegradable & eco-friendly. Responsibly sourced with plastic-free packaging.
I've been using this for a year or so now, for hand and body wash and bench spray. Love the quality and knowing if my kids ate it they wouldn't get sick!
I really enjoy making my own household cleaning products - all the ingredients from Under Your Sink are top notch!!
I like to buy aussie made, made my first batch of dishwashing liquid and had soap from the website. Couldn’t be happier. The service Analise provides is outstanding.
Fantastic Service and Products
These were exactly what I’d hoped for - excellent quality, everything feels really well made. And thank you for the extra little gift. So generous and kind!! xoxo
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