Ingredient Article #1 - Lye

Today I am going to begin a series of articles that will explain common ingredients that are used in the making of soap, skin and bath products.

Lye (Sodium Hydroxide)

Lye (NaOH, sodium hydroxide) is a white caustic soda easily dissolved in water and other liquids.

The lye that is purchased commercially today is derived from running an electrical current through salt water.

Lye is commonly used in various methods of soap making. It is also used in the manufacturing of pulp and paper, detergents, textiles, vegetable oil refining, and water treatments.

Lye is classed as being in the upper limit of the PH scale, and is highly dangerous once it is added to a liquid. Lye and water, for example, produces heat, and can burn skin and eyes, therefore, precautionary measures (such as goggles and gloves) are absolutely necessary when working with the product. Lye can also react to a small amount of moisture, such as humidity in the air. The product must always be kept in an airtight container. If spilled, it must immediately be disposed of properly.

Soap has been around for thousands of years, but for the sake of writing space, we are going to go back to the colonial and pioneer eras to look into the history of how soap was made. Soap was available in general stores in the 1850's, but many women made soap at home during that era. It was not uncommon for a group of women to gather together to make soap in very large batches a couple of times a year.

My first question was, how did the families make their own lye? People heated their homes and cooked using fire. The hardwood ash remaining from those fires was the base ingredient in lye. The ash was placed in a box or kettle, sometimes called a "leacher" box, set up just for lye making purposes. Water was then added to the ash. Slowly, sometimes for an entire day, the water leached through the ash. The final product was lye (the leached water) which was collected for soap making.

In the early logs in history, it is told that fat from meat processing was rendered, cleaned and filtered, and added to the lye, which began the saponification process (the process of fats turning to soap). As the mixture thickened it was poured into large crates. Days later the soap was cut into bars. The bars were left to cure, become mild, and harden, which took approximately a month to complete.

We are much more precise in our soap making processes today. Many of us use vegetable oils in our soap recipes. Many of us test our soaps, so we know that our end product (soap that has cured for 6 weeks) is very mild, with a low pH value. Our basic process lye+fat has not changed in a considerable way, but the result is a much cleaner, uniform, and skin loving product.