Why Use Lye in soap?
One of the most asked questions when I get a new customer whom is purchasing my soap is “Why do you use lye in your soap?” The simplest answer is you don’t get soap without the use of lye.
Lye also known as sodium hydroxide must be used in the process of making soap. A chemical reaction between the lye solution (lye and water, milk, beer or other liquid) and the oil, called saponification occurs and changes the oils to soap. Saponification is the process where the fats in the oils are converted to soap (fatty acid salt) and glycerol. Upon completion of the saponification process no lye remains in the soap just the fatty acid salt (soap), glycerol and the unsaponifiables from the oils or fats used. Unsaponifiables are components of an oily (oil, fat, wax) mixture that fail to form soaps when blended with sodium hydroxide (lye).
There are pages upon pages of this chemical process if you need a more scientific explanation you will find links at the end of this blog. At the end of the saponification process no lye remains and the oils are fully converted. Soaps that are truly soaps are all made in the same process. There are several types of lye(which is the laymen term) Sodium hydroxide is used to make solid soaps and Potassium hydroxide is used to make liquid soaps.
Per Wikiedia -“A lye is a liquid metal hydroxide obtained by leaching ashes (containing largely potassium carbonate or “potash”), or a strong alkali which is highly soluble in water producing caustic basic solutions. “Lye” is commonly an alternative name of sodium hydroxide (NaOH) or historically potassium hydroxide (KOH), though the term “lye” refers to any member of a broad range of metal hydroxides.”
If no lye is used the soap product is actually a DETERGENT and not an actual soap.
I choose to label my products appropriately with the ingredient of lye listed. After Saponification occurs no lye actually remains in the soap. Many soap makers out there choose to label there products in such a way the the consumer isnt aware of the lye. EX. Saponified sustainable palm, olive oil and coconut oil or they may choose to use Sodium olivate, Sodium palmate and Sodium cocoate (INCI terms) all of which indicate an oil altered by sodium hydroxide or potassium hydroxide. In the end you have oil with lye making soap.
Have you ever wondered why they don’t list ingredients on the bottle of dish detergent? Well the FDA does not require it on those products but has strict rules for cosmetics. Some food for thought.
I would love to hear from you and answer any questions that you might have.
Have a Blessed day
For more information here are few links: