Lye gets an unfair reputation...

Lye gets an unfair reputation, even though it’s essential to real soap.

 

Lye is an essential ingredient in the soap making process as it transforms fats and oils into “soap”. This process is called saponification. This results in a product that is not only safe for our skin and bodies, but also beneficial. Lye soap that is properly made provides moisturizing properties that us effective fir cleansing without leaving any harmful residues.

 

What Is Lye?

Lye is sodium hydroxide, a natural mineral-based alkali traditionally made from ash and water. It’s the key ingredient that turns oils into true soap through a process called saponification. There are some safety concerns and misconceptions to learn about. While lye is caustic in its raw form and requires careful handling, it is completely safe in the final soap product. The saponification process ensures that no lye remains in the finished soap. Properly made lye soap can be gentle and beneficial for various skin types, including sensitive skin.

But what is saponification, really?

Saponification is the chemical reaction that occurs when lye (sodium hydroxide or potassium hydroxide) reacts with fats or oils to produce soap. This process is essential for creating soap, as it transforms the raw ingredients into an actual cleansing product. This chemical reaction involves the breakdown of fats or oils into soap or glycerin, and this is quite necessary in making soap. Soap cannot be produced without the saponification process.

 

Without lye, soap is not soap—it’s a detergent.

 

Is There Lye in Finished Soap?

No. Plain and simple.

When properly formulated and cured:

 

  • Lye is fully used up during saponification

  • It chemically transforms oils into soap and glycerin

  • Finished bars contain zero free lye

 

This is why handcrafted soap is safe and gentle for skin. (That is, assuming added toxins are not brought in.)

 

Why Using Lye Is Actually Beneficial for Skin

The benefits don’t come from lye itself—but from what lye makes possible.

 

1. Creates Natural Glycerin (Major Skin Benefit)

Saponification produces glycerin, a powerful natural humectant.

 

  • Draws moisture into the skin

  • Helps keep skin soft and hydrated

  • Supports the skin barrier

 

Commercial soaps often remove glycerin while handmade soaps keep it. This glycerin content is the reason our HHN soaps “sweat”.

 

2. Allows Soap to Be Superfatted

Artisan soap makers (like HHN) use extra nourishing oils beyond what lye can consume. This is called being “superfatted”.

 

This means:

 

  • Extra oils remain in the bar

  • Skin feels conditioned, not stripped

  • Ideal for dry, sensitive, or aging skin

 

Let’s explain what “superfatted’ is. Superfatting refers to the practice of adding extra fats or oils to the soap mixture after saponification is complete or ensuring that not all lye is consumed in the reaction. This process results in a soap that contains unreacted oils. I like to add fats like honey or beeswax and oils like castor oil and olive oil to my soaps. These fats and oils also help the soap to bubble and foam. Superfatting provides additional moisturizing properties, making the soap less drying on the skin as well as enhances the soap’s overall feel.

 

3. Produces a Gentler Clean

True soap made with lye:

 

  • Cleans without synthetic detergents

  • Preserves the skin’s natural oils

  • Leaves skin balanced instead of tight

 

This is especially important for mature or compromised skin barriers.

 

4. Supports Skin’s Natural pH Recovery

While soap itself is alkaline, well-formulated natural soap:

 

  • Rinses clean

  • Allows skin to quickly return to its natural pH

  • Avoids prolonged irritation seen with harsh detergents

 

 

Why “Lye-Free Soap” Is actually a Red Flag

If a product claims to be lye-free, it is:

 

  • A detergent bar or melt-and-pour base

  • Made with synthetic surfactants

  • Often harsher on skin long-term

 

Natural, traditional soap must use lye—there is no exception.

 

Lye is essential for turning nourishing oils into real soap, creating naturally moisturizing glycerin and a gentle cleanse—without any lye remaining in the finished bar. Now we know, lye plays a vital role in soap making, providing both cleansing and moisturizing benefits. When used correctly, it contributes to the creation of high-quality, natural soaps that are safe and effective for human use.



 

 

Sources:

https://www.grandmaslyesoap.com

https://www.soapqueen.com

https://www.legendscreekfarm.com

 

Laura HillComment