Here’s how I turn my handmade olive oil castile bars into a lovely liquid soap. I really like how it feels and use it for household cleaning, dishes, bathing, shampooing, laundry, bathing pets, and more.
For the price of a 3-oz bar of castile soap, you can make 18 to 25 ounces of liquid soap (depending on how thick/thin you want your liquid soap). Now, that is making your soap and dollar stretch a long, long way.
By the way, this article is a revamp of an article I wrote in 2017 for my old website. It’s been updated and revised accordingly.
Liquid Castile Recipe
Liquid castile soap often costs a pretty penny, so making it from a hard bar is ideal for making it more affordable. To make this recipe more doable at home for most folks, I’ve stuck to tools and supplies you are likely to find around the house.
Items you will need are:
- A large pot with a lid (I’m using a 3-quart saucepan)
- Distilled water (adding water to anything introduces an opportunity for germs and bacteria, so use distilled water or purified water, or at least boil your water…never use plain tap water)
- a bar of soap
- a whisk for stirring
- a cheese grater
- Kitchen scales if you aren’t comfortable eyeballing it
Be sure all of your tools are clean and dry when you start.
The Process
In the photographs, you can see I am making a sizable batch of liquid soap.
I am using a 3-quart saucepan with a lid, starting with 40 ounces of water, and 8 ounces of bar soap. The ratio you want to keep in mind for your recipe is 1 part solid bar soap to 5 parts water. That means for every one ounce of solid bar soap, you will need about 5 ounces of water to dissolve it, as well as a pot large enough to contain it.
First, you will need to grate the soap bar. The cheese grater in your kitchen will work beautifully. The finer the soap flake, the easier it will dissolve in the water. Once the soap is grated, place the soap flakes in a bowl and set it aside.
If you are using plain tap water, measure the water into the pot and bring it to a boil. Boil it for several minutes to kill off any pathogens it may contain. Then, remove the pot from the burner and turn off the heat.
Add the soap flakes. Spoon them into the water (please be very careful not to splash hot water on yourself) and give them a good stir. Cover the pot with the lid and let it cool to room temperature. Stir it occasionally to ensure it is coming together properly.
Dissolving the Soap
The next set of pictures will show you the stages the soap goes through as it dissolves.
Soap flakes are added to hot water. Stir well, cover, and let sit.
Here is what the soap looks like at the four-hour mark. It is still a little too chunky, so I’ve added four tablespoons more hot water and some heat to help with melting. Remember to add small amounts (a tablespoon or two) of boiled water at a time and gently stir.
A couple of hours later, now this is what I had been hoping to see: lovely, smooth, thick, semi-translucent soap. The white on the top is foam from stirring so much. The foam is just soap. However, if it bothers you, feel free to skim it off.
This soap has a pretty amber honey color. It is thick but still easy to use. It has a nice pour and a low, creamy lather. The scent is minty with a hint of lemon and roses (I used a bar of my Peppermint Castile and a piece of a Lemon Rose French Pink Clay Castile).
It’s time to bottle the soap for use. Be sure the vessel is clean and dry. Store your soap out of direct sunlight and away from heat. Under the sink or in a linen closet is perfect.
Troubleshooting
In case something goes awry, here’s how to fix it. Say the soap is too thick and gloopy. Start by stirring in another ounce or two of HOT distilled water. Use the whisk to incorporate the water into the soap, stirring gently until it reaches the desired consistency.
Allow the soap to cool after each addition before adding more water.
You could also preheat the OVEN to 175*, turn it off, and place the covered soap pot inside the oven. Sometimes, a little external heat helps loosen the soap enough to dissolve.
Oops again. What happens when you’ve added too much water and the soap is now thin?
Leave the lid off the pan and let the excess water evaporate. The evaporation process typically takes only a day or two, but it may take up to several days, depending on how thin the liquid soap is and how thick you want it to be.
Remember, this is not rocket science; it’s just soap. It is very easy to adjust and correct mistakes. Even if you mess it up, it still works as laundry soap.
In a Nutshell
This recipe is easy to follow when in a pinch! I’ve done it multiple times at home and in an RV. You can intensify the scent and cleaning properties even further by adding a few drops of your favorite essential oil. Enjoy!