Homemade liquid castile soap

Updated February 21, 2017

Making your own soap can save money as well as time. It can also ensure that the products you use on your skin are natural and chemical free. Making homemade liquid Castile soap isn't difficult, and it is good for use on hands as well as dishes and for cleaning. Try your hand at making liquid soap for your own use, and consider making some for gifts, as well.


Gather a few ingredients and tools to make homemade liquid Castile soap. Purchase some sunflower oil, potassium chloride (available at drugstores) and distilled water. The combination of the distilled water and potassium chloride will result in the formation of lye.

You will need access to tap water as well as a hand-held stick blender and any essential oils you'd like to use for fragrance. A crock pot is necessary, as are mixing and measuring tools.


Pour 473ml. of sunflower oil into your crock pot, with the heat on high. In a separate bowl, mix 156gr. of potassium chloride with 454gr. of distilled water. Add this lye mixture to the warm oil in the crock pot. Mix this all together using a hand-held stick blender on low. You may stir by hand with a wooden spoon, but the hand-held stick blender will make the task easier. The mixture will likely appear as though it is going to separate. This is normal. Just keep mixing.

The mixing of your ingredients will create a pasty consistency. Now pour 1134gr. of tap water into the crock pot. Combine this with the paste using your hand-held stick blender.


Leave the mixture in your crock pot and check it every hour or so. If it is separating, mix it for a minute with the stick blender. If not, simply give it a stir with a wooden spoon. The consistency should go from paste to an applesauce-like consistency. From there it should become smooth, although still quite thick--sort of like pudding. At some point in the cooking, it may even become hard and sticky like taffy. If this occurs use a potato masher to break it up. Within a couple more hours it should transform to the consistency of petroleum jelly. At this point you'll know your liquid Castile soap is almost done.


It is now time to test the soap to see if it is done. Boil some water in a tea kettle, and measure 56.7gr. into a clear measuring cup along with 28.4gr. of the soap mixture. Stir it with a spoon until the soap dissolves in the water. If it appears to be a little bit cloudy, that's OK. You don't, however, want it to appear milky. This may indicate that the soap hasn't cooked long enough or that you haven't measured the oil properly. Try cooking it a bit longer and test it again if that is the case.

If the clarity is just a bit cloudy, it's time to add a few drops of essential oil for scent. Simply add your scent of choice. Six to eight drops is usually enough to produce a strong, but not offensive scent.

Pour your warm liquid Castile soap into bottles or jars and allow it to cool before using.

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About the Author

Kimberly Ripley is a freelance writer and published author from Portsmouth, N.H. She has authored five books and hundreds of articles and short stories. Her work has appeared various publications, including "Parenting," "Writer’s Digest," "Vacations" and "Discovery Travel." She studied at the University of Maine and later pursued her writing studies through numerous classes and workshops.