We are in an age where there is significantly more emphasis on living and eating as healthy as possible. With that, many people have eschewed the use of chemicals. However, there are some materials, which are labeled as chemicals, which are derived from nature and serve valuable purposes. So what is lye and how is it used in soap making? Handcrafted soap from scratch cannot be made without lye and the history of lye in soap-making is long and rich. However, for the blog today we are focusing on how and why lye is made and its multiple uses.

Lye is an alkali, also known as a base (versus an acid). Alklais range from weak to strong. The baking soda which you use in making cakes or cookies is a weak alkali. A strong one is sodium hydroxide (NaOH) which has been used as a drain cleaner. In this case, the alkali converts the grease blocking the drain into soap which allows you to flush it away.

All soap is simply just that, an alkali salt of fatty acids. In soap making, all the lye is consumed in the saponification process and no residual remains. The modern soap making process has been revolutionized by artisans, using only the best and most nourishing fatty acids (olive oil for example) to create healthy, moisturizing, skin loving bars.

How is lye made today?

Sodium hydroxide (NaOH) is made using the chloralkali process.  Actually Lye is a converted form of SALT, made from sodium chloride (NaCl) or table salt.  Today lye is made by passing an electrical current through a sodium chloride (NaCl) solution.  Through the use of a special membrane, the resulting NaOH (lye)solution is allowed to exit the cell and be collected while the other products remain behind.  The lye is further reduced and sold in flakes, beads or pellet form.

There are two types, Industrial/Technical grade and Food Grade.

Industrial lye is used where the primary interest is caustic power.  It is used in the manufacture of textiles, paper and detergents. Some common household products that use lye are oven and drain cleaners. Red Devil Lye was the most famous version, found in hardware stores for many years. Red Devil was removed from the market due to health risks from heavy metal impurities.

Food grade lye is used to cure many types of food such as olives, Lutefisk, hominy, canned mandarin oranges and pretzels.   It is also used in the manufacturing of Japanese ramen noodles. In order for it to be used on food, it must meet stringent purity requirements outlined by the Food Chemical Code (FCC) written by the Food and Drug Administration.  Food grade lye is highly processed with very, very few impurities.   Food grade lye is the only type that should ever be used in soap-making.

Why is Lye Important?

Historically, Lye was an important ingredient in the home during the late 1800’s – early 1900’s. The following excerpt is taken from “Babbitt’s in the Home”, a pamphlet published in 1923 by B.T. Babbitt, a lye manufacturer.  In the Forward section of the pamphlet, the introduction reads:

“Nearly all foremost household experts and domestic teachers recommend the modern housewife use Lye.  They say that no home is really clean and sanitary unless lye is used. Lye is both a disinfectant and a cleanser.  Lye is particularly suitable to kill germs and bacteria as well as cleaning the surface of food containers, room vessels, the surface of wash bowls, etc.  Other disinfectant uses are the washing of floors and walls, and a very important use is keeping the garbage can clean and sweet. Lye is probably one of the most efficient and economical disinfectants known to scientists and will enable a woman to keep her home and family’s health safe from disease.”

The pamphlet goes onto describe lye as the desired cleaner for refrigerators (and virtually everything else) by using a ½ teaspoon full to a gallon of water, thereby “keeping the area scrupulously clean and safe for eatables.”  Today, most people use a diluted bleach solution (sodium hypochlorite – NaCIO) to disinfect, clean and whiten.  However historically, it is helpful to realize what an important role lye once played in the early American home.