This article will show you how to make your own castile bar soap. If you enjoy using natural soaps, this will show you how save money making it yourself for about $1 US per bar.
First something that needs to be said about soap. There is NO WAY to make bar soap without using lye. It is a physical impossibility. The basic reaction that is needed to make soap, called ‘saponification’, cannot happen without some form of lye reacting with some form of oil. Lye is actually a general term for a very strong alkali (the opposite of acid on the PH spectrum). There are generally two alkali’s that are used in soap making, sodium hydroxide and potassium hydroxide. Both are considered lye, but the potassium hydroxide is not strong enough to make a solid soap. It is only used for making the liquid soaps in today’s world.
Soap manufacturers today do everything they possibly can to hide the fact that they use lye in their soap. They have made up lots of names to hide it. Dr. Bronners soap, which many naturalists are in love with as a natural soap, uses lye. They hide the fact in their ingredients list by saying that they use “saponified oils”, which is the process of mixing lye with oil. The public is afraid of the word lye, but they have no idea that it is used in every bar soap ever made. Soap simply cannot be made without it.
The important thing in any soap recipe is using the proper proportion of lye and oil to form a PH neutral soap when completed. In times of old, soap makers were not using a pure form of lye in their recipes. The PH of the lye was not consistent, so their end product could end up being very alkaline, and burn the skin. The story of “lye soap” burning the skin has been passed through the generations, creating public fear of the word. When properly used, lye is our friend. Lye (sodium hydroxide in this case), when mixed in the proper proportions with hydrochloric acid, produces a strong chemical reaction resulting in table salt, something we have been eating for hundreds of years.
The recipe below uses the proper proportions of oil and lye to create a PH balanced soap that will be very mild to the skin.
Here are a few tools you will need:
- A digital scale capable of 5 lbs measurement.
- 2 glass bulb thermometers that can measure up to 200° Fahrenheit.
- A stick blender.
- A high temperature plastic jar (to mix the sodium hydroxide and water).
- A long-handled plastic mixing spoon.
- A ladle.
- Two large plastic bowls.
- Soap molds.
Here is the recipe:
- All measurements are in weight – not fluid ounces.
- All bars are assumed to be 4oz.
| Full Batch |
Half Batch |
Quarter Batch |
| Makes 28 bars |
Makes 14 bars |
Makes 7 bars |
| 24oz Cold Distilled Water |
12oz Cold Distilled Water |
6oz Cold Distilled Water |
| 12oz Sodium Hydroxide (lye) |
6oz Sodium Hydroxide (lye) |
3oz Sodium Hydroxide (lye) |
| 74oz Olive Oil |
37oz Olive Oil |
18.5oz Olive Oil |
| 14oz Coconut Oil |
7oz Coconut Oil |
3.5oz Coconut |
Caution: Whenever working with Sodium Hydroxide it is recommended as a safety precaution that you use rubber gloves, goggles, and any other protective gear that you may want to use in order to protect your skin or clothing from accidental splashes of the liquid.
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Add lye to water in a high temperature plastic container outside of house. Do not breathe fumes. Always add Lye to water (not reverse). Caution: Temperature of mixture will rise to approximately 195ºF. Stir mixture with plastic spoon.
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Mix oils and microwave to 110ºF.
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Allow lye to cool (place in bowl of cold water to speed up cooling).
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When both solutions are at 110ºF, add lye solution to the oil mixture. Blend with stick blender until the mixture reaches “trace” where you can see a film on top of the soap that traces the line of the stick blender. Ladle into molds.
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Handle bars with care for next two days. PH will be high and can burn the skin for the first 48 hrs. The PH will settle to neutral after this.
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Place molds in freezer for 30 minutes to help separate the soap from the molds.
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Allow 6-8 weeks to air dry before use.
Distilled water is used to guarantee that the PH of the soap will be neutral when complete, and that no impurities are in the water that could affect the saponification process. Distilled water can be purchased at any shopping center in a one gallon container.
Lye (Sodium Hydroxide) can be purchased locally at any Lowes home center, and now Tractor Supply carries it too. A two-pound container of Roebic Crystal Drain Cleaner is available for just over $12. Make sure you buy the one that says 100% lye. Or, you can purchase it in bulk HERE. Two pounds are plenty to last more than two full batches.
Please note that sodium hydroxide is considered a hazardous substance, and shipping prices increase significantly because of this. It is also used in manufacturing certain illegal drugs, and some states may regulate the sale of lye for this reason.
Soap molds can be purchased HERE or at many other internet soap supply retailer.
How to make your own Castile Soap like Dr. Bronners from Frugalberry.com on Vimeo.
I now have an article posted on how to use this bar soap to make your own liquid castile soap. Check it out HERE.
