lye | Earthoria

This article will show you how to make your own castile soap bars. Buying natural or organic soap is very expensive today and unfortunately the healthy choice has become the expensive choice. And even if you are willing to pay the price for seemingly “natural products”, you will often find a long list of chemicals (non-natural additives) on the ingredient label on the back and think “what on earth is all this?”

I will advise you to never buy a product only judging from its name, because names these days are very deceptive (e.g. “herbal essence” which not only contains lots chemicals such as the carcinogen 1, 4-dioxane, which is known to cause cancer, but they also test on animals) and there is far between real natural products without chemicals inside.

This is what inspired me to make my own soap, deodorant, toothpaste, and cream. I simply couldn’t find products without chemicals – or rather I found very few (such as Miessence) but they are very expensive.

Making your own products is fairly simple, cheap and joyful….since you will be 100% sure that no additives have been added.

The recipe below uses proportions of oil and lye to create a PH balanced soap that will be very mild to the skin.

Here is the recipe for 7 bars of olive oil castile soap:

• 150g/ 164 ml coconut oil
• 538 g/ 580 ml olive oil
• 190-220 ml cold water
• 92 g lye /sodium hydroxide/ caustic soda
• 20 drops lemon oil (can use any kind of pure oils)

Alternatively you can make a double portion with half coconut oil and half olive oil. This will give you 14 bars of castile soap:

• 688 g coconut oil
• 688 g olive oil
• 509 ml cold water
• 198 g lye /sodium hydroxide/ caustic soda
• 1 tea spoon of lemon oil (you can use any kind of pure essential oil)

Here are the tools you need:

• A digital scale
• 2 thermometers that can measure up to 93° Celsius/ 200° Fahrenheit.
• A stick blender.
• 1 high temperature plastic jars (to mix the sodium hydroxide and water). I use a plastic bucket
• 1 plastic bucket to mix the sodium hydroxide mix with the oil mix)
• 1 glass bowl for lye
• 1 ceramic bowl for heating up the oil in the microwave
• A long-handled plastic mixing spoon.
• A ladle.
• Soap molds – alternative you can use a water bottle (1.5 liters) and cut it open when taking the soap out.

Caution: Whenever working with lye you should use rubber gloves, protective glasses and long sleeved skirts and pants to protect your skin from accidental splashes of the liquid.

How to make the soap:

1. Add lye to water in a high temperature plastic container somewhere with fresh air (outside your house). Do not breathe fumes. Always add Lye to water (not reverse). Caution: Temperature of mixture will rise to approximately 91ºC / 195ºF. Stir mixture with plastic spoon.
2. Allow lye to cool (place in bowl of cold water to speed up cooling).
3. Mix oils and microwave to 43º C/ 110ºF (that’s about 2 minutes in my microwave).
4. When both solutions are at 43º C/ 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.
5. Leave it in the mold for the 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.
6. Place molds in freezer for 1 hour to help separate the soap from the molds.
7. Use plastic gloves when handling the soaps the first month.
8. If you use a plastic bottle to pour inside the liquid soap mix, cut up the bottle and take out the hardened soap mass and cut it into pieces.
9. Place the soaps on paper.
10. Allow 6-8 weeks to air dry before use.

Distilled water can be 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. In Denmark I just use tap water since that’s perfectly thing (very fortunate).

Lye (Sodium Hydroxide) can be purchased in cleaning section of many supermarkets. Make sure you buy the one that says 100% lye/ caustic soda/ sodium hydroxide.

I wish there was such a thing as a completely natural soap made only from coconut oil, olive oil, essential oils etc. But this is unfortunately impossible. There is absolutely no way to make a bar soap without using lye.

The basic reaction that is needed to make soap, called ‘saponification’, cannot occur without some form of lye reacting with some form of oil. Lye is actually a general term for a very strong alkali. There are two alkali’s that can be used to make soap: sodium hydroxide (caustic soda) 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 liquid soaps.

Therefore sodium hydroxide cannot be substituted for potassium hydroxide and vice versa because soap making recipes will have different quantity requirements for these two chemicals depending on the kind of soap being manufactured. In addition, the quantities required for soap saponification differ when using caustic soda and hydrated potash.

Soap manufacturers do everything they can to hide the fact that they use lye in their soap. Dr. Bronners soap, which is considered “pure” natural, uses lye. It is hidden under the term “saponified oils”, which is actually the process of mixing lye with oil. Soap simply cannot be made without lye.

Lye is commercially manufactured using a membrane cell chlor-alkali process. It is one of the highest volume industrial chemicals with an annual production of 40 million tons. It is supplied in various forms such as flakes, pellets, microbeads, coarse powder or a solution. I use flakes to make soap – but would use any form available.

Interesting enough, Lye is also used for other things:

Food uses: Lye is used to cure types of food, such as: lutefisk; olives (making them less bitter); canned mandarin oranges; pretzels etc. It is also used as a tenderizer in the crust of baked Cantonese moon cakes, and in lye-water “zongzi” (glutenous rice dumplings wrapped in bamboo leaves); in chewy, southern Chinese noodles popular in Hong Kong and southern China; plus, in Japanese ramen noodles.

Household uses: Lye is also valued for its cleaning effects. It is commonly the major constituent in commercial and industrial oven cleaners and clogged drain openers, due to its grease-dissolving abilities. Lye decomposes greases via alkaline ester hydrolysis, yielding water soluble, easily removed (e.g., rinsed away) residual substances.

It does have hazardous reactions and has a potentially destructive effect on living tissues (e.g., skin, flesh, and the cornea). Solutions containing it can cause chemical burns, permanent injuries, scarring, and blindness—immediately upon contact. Lye may be harmful or even fatal if swallowed; ingestion can cause esophageal stricture. Moreover, solvation of dry solid lye is highly exothermic; the resulting heat may cause additional burns, or, ignite flammables. Therefore it is extremely important to use personal protective equipment including safety glasses, chemical-resistant gloves, and adequate ventilation when using lye to make soap (or clean your drain).

The reaction between sodium hydroxide and a few metals is also hazardous. Aluminium reacts with lye to produce hydrogen gases. Since hydrogen is flammable, mixing a large quantity of lye (e.g., sodium hydroxide) and aluminum in a closed container is dangerous – especially when the system is at a high temperature, which speeds up the reaction. In addition to aluminum, lye may also react with magnesium; galvanized zinc; tin; chromium; brass; and, bronze—producing hydrogen gas. Therefore I always use plastic containers and glass when I make soap.

DIY: How to make pure castile soap?

Does 100% non-chemical soap exist? No – Lye is always used