If you use natural body care products, you probably have heard of Bronner’s Castile Liquid Soap. People call it the “Swiss-army knife” of soap. It’s an all natural liquid Castile soap that has a ton of uses. Use it as a body wash? Yep. Liquid Castile soap is gentle enough for people with the most sensitive skin. Use it as a shampoo? Yep, even on babies’ hair. Use it as a dishwashing detergent? Yep. Use it as a laundry detergent? Yep.

Dr. Bronner’s Pure-Castile Liquid Soap is great. Except one thing! It contains palm kernel oil. Palm oil production has led to “deforestation, habitat degradation, climate change, animal cruelty and indigenous rights abuses.” I explained in detail why I don’t use palm oil, including the so-called fair trade or sustainable palm oil in this post.  No Dr. Bronner’s Castile Liquid Soap for me. Instead, I make my own DIY liquid Castile soap. It can do all that Dr. Bronner’s liquid Castile soap can do. Want to know how I make it? Read on!

What is Liquid Castile Soap?

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Liquid Castile soap is a liquid soap that’s made with olive oil. Olive oil soap has been made and used for millennia. It’s popular because it’s gentle on our skin. It can be used by people with the most sensitive skin, like babies and children. The first olive soap is the Aleppo soap, made in Aleppo, Syria. Yes, the same Aleppo that has been on the news, but for very unfortunate reasons. During the 11th and 12th centuries, the Castile region of Spain began to make its own olive oil soap. That’s why we now call olive oil soap “Castile soap.”

Castile soap often isn’t made with only olive oil. For example, Dr. Bronner’s Fair Trade & Organic Castile Liquid Soap is made with 5 different kinds of vegetable oils: (1) coconut oil, (2) palm kernel oil, (3) olive oil, (4) hemp oil, and (5) jojoba oil. The order of the ingredients tells me that this Dr. Bronner’s liquid Castile soap has more coconut oil, and palm kernel oil, than olive oil. My educated guess is that Dr. Bronner’s Fair Trade & Organic Castile Liquid Soap is made with approximately: (1) 35% coconut oil, (2) 30% palm kernel oil, (3) 25% olive oil, (4) 5% hemp oil, and (5) 5% jojoba oil. Let me know if you want to know how I come up with these educated estimates. I can give you a detailed (and a total nerdy) explanation on these percentages. 🙂

DIY Liquid Castile Soap

Prep Time: a day or 2. Making DIY liquid Castile soap involves cooking the soap for about 5 hours, and then waiting another 10 to 12 hours for the soap paste to dilute and turn into liquid Castile soap.

Yields: about 55 oz of DIY liquid Castile soap

Ingredients for DIY Liquid Castile Soap

1. Coconut Oil – 10 oz. I use Trader Joe’s Organic Virgin Coconut Oil. You can also use other brands of pure coconut oil, like Carrington Farms Organic Extra Virgin Coconut Oil, or Viva Labs Organic Extra Virgin Coconut Oil.
2. Olive Oil – 4 oz. I use Trader Joe’s Imported Olive Oil. You can also try other brands of pure olive oil, like La Tourangelle Extra Virgin Olive Oil, or Kirkland Organic Extra Virgin Olive Oil.
3. Hemp Oil – 1 oz. I use Nutiva Organic Hemp Oil. Other brands of hemp oil works too, like Canada Hemp Foods Organic Hemp Oil, or Dr. Adorable Organic Hemp Seed Oil.
4. Jojoba Oil – 1 oz. I use Now Foods Organic Jojoba Oil. You can also try Leven Rose Organic Jojoba Oil, or Radha Beauty Organic Jojoba Oil.
5. Potassium Hydroxide (KOH, aka lye) – 4.1 oz. I use Mollys Products Potassium Hydroxide Flakes. Make sure you use potassium hydroxide, not sodium hydroxide. You use sodium hydroxide to make hard soap bars.
6. Distilled Water – 6 oz to make lye solution.  An additional 34 oz to dilute DIY liquid Castile soap paste. You can find distilled water in your local supermarket.
7. Vitamin E – 25 drops. I use Now Foods E-Oil. You can also use Sundown Vitamin E Oil, or Trader Joe’s Vitamin Oil E. 
8. Glass Container – a 1/2 gallon glass container.

Ingredients Compared

To make DIY liquid Castile soap, I use all the ingredients found in Dr. Bronner’s Castile Liquid Soap, except palm kernel oil and citric aid.

Dr. Bronner’s Castile Liquid Soap	DIY Liquid Castile Soap
Water	Water
Coconut Oil	Coconut Oil
Potassium Hydroxide	Potassium Hydroxide (KOH, Lye)
Palm Kernel Oil
Olive Oil	Olive Oil
Hemp Oil	Hemp Oil
Jojoba Oil	Jojoba Oil
Citric Acid
Tocopherol	Tocopherol (Vitamin E)

How to Make DIY Liquid Castile Soap

Be sure to take all necessary precautions when working with lye. You can read more about suggested protective gear in this post. It’s never a good idea to work with lye when children or pets are around.

(1) Make lye solution.  In a well-ventilated place, add 4.1 oz of Potassium Hydroxide (KOH) to 6 oz of distilled water. Never add water to lye.

Use a silicone spatula to carefully mix your lye solution. Set the lye solution aside. When it’s ready for use, it will turn from cloudy to clear. It took about 10 minutes for me.

(2) Add coconut oil, olive oil, hemp oil and jojoba oil in a crock pot.  Turn the crock pot to high heat to melt and mix the oil.

(3) Once all the oil is melted and mixed, carefully pour lye solution into the crock pot.

(4) Mix oil and lye solution using a silicone spatula for a few minutes. Then use a stick blender to bring the mixture to light trace (vanilla pudding consistency). It will take a little time, at least 15 to 20 minutes.

(5) Cover your crock pot. Cook your DIY liquid Castile Soap at high heat. For the first hour of cooking, check every 15 minutes to see if your soap has separated (it happened to me!), or has escaped outside of the crock pot.

(6) If your DIY liquid Castile soap separated. Use the stick blender to mix it again, and bring it back to trace. It took me about 5 minutes.

If your DIY liquid Castile soap tried to escape the crock pot, use a silicone spatula to stir the soap mixture. That should deflate it.

(7) Cover your crock pot again.  Cook your DIY liquid Castile soap on high heat for 5 hours.

Here is my DIY liquid Castile soap after 4 hours of cooking.

Here is my DIY liquid Castile soap after 5 hours of cooking.

(8) Do a hot water test. Add 1/2 oz of the DIY liquid Castile soap to 1 oz of hot water. If the soap melts and the soapy liquid isn’t super cloudy (see picture below), the soap is ready to be diluted. If the soapy liquid is very cloudy and milky, then cook the DIY liquid Castile soap for another 30 minutes. And repeat the hot water test.

(9) Add 34 oz of VERY HOT distilled water into the crock pot. Make sure it’s very hot water. Otherwise your crock pot might crack due to the temperature difference. I use boiling hot water.

(10) Use a silicone spatula to mix the soap paste and the hot distilled water. Turn off your crock pot and cover it with the lid. In about 10 to 12 hours, your soap paste will be completely diluted.

It’s a good idea to use PH testing strips to check the PH-level of your diluted soap. You want your soap to have a PH-level between 8 and 9.

(11) Add about 25 drops of vitamin E to your diluted soap. Pour your DIY liquid Castile soap into a glass container.

That’s it! This is how you make your very own DIY liquid Castile soap. This is an all natural liquid soap that has many uses. If you use it for body or hair care, I would add 1 part of glycerine to 3 parts of DIY liquid Castile soap. Adding glycerine to the liquid soap will make it more moisturizing, less drying. If you want to use the DIY liquid Castile soap for cleaning or to do laundry, you can use it without adding anything else. If you want to add a natural scent to your DIY liquid Castile soap, you can add lavender essential oil or lemon essential oil. This DIY liquid Castile soap doesn’t need curing. But if you leave it alone in a glass container for a few weeks, it will become more transparent, and even more mild, with a lower PH-level.

So, will you be making your own Dr. Bronner’s inspired DIY liquid Castile soap? I’d love to know how you like the recipe. As always, if you like this DIY liquid Castile soap recipe, please pin it and share it!