The Truth About Lye and Soap

“Why would anyone want to use something as caustic as lye on their skin?”

Spa Essential Oil. Aromatherapy.No Lye, No Soap
We had a customer ask that question recently. We also had a guy on the phone comment that “lye doesn’t seem very organic, man.” And by “organic,” he meant groovy. On the organic point, he was right. Lye isn’t organic, but  it is one of the allowable non-organic ingredients included in USDA organic standards since their inception. On the groovy point, we disagree. The truth about lye in soapmaking is simple. There is no true soap without lye (check the FDA definition), and there’s a huge difference between “made with lye” and “containing lye.”

None of this is news to people in the soap business. For the public at large, though, and even for some soapmakers, the subject can be confusing. Lye, after all, is also known sodium-hydroxide150x150as caustic soda, and soap made from lye is what frontier women made in cauldrons that was great on clothes but murder on skin.

Many perceptions of lye have nothing to do with modern soapmaking. But if you’re in the business of making or selling soap, these perceptions persist and are part of your life. The good news is, you can always fall back on chemistry, which is where the truth lies. You’re not using lye on your skin. You’re using soap.

The Chemistry of Soap
Here’s the truth to fall back on. Soap is the result of a chemical reaction called saponification that occurs between lye and a tSoap in Moldsype of molecule called a triglyceride (a fat or oil), where both substances are chemically transformed, creating soap and natural glycerin. Neither of the original ingredients exists anymore. All the lye – either sodium hydroxide for bar soap or potassium hydroxide for liquid soap – is consumed in the reaction.

So, while soap is made with lye, it doesn’t contain lye. Modern methods and measuring scales – as opposed to what was available to frontier women – allow soapmakers to use the proper mixture of oils and lye, ensuring that all lye is consumed. In addition, many soapmakers, including Botanie Soap, add more oil than is required for the chemical reaction, further ensuring the neutralization of lye and adding to the soap’s moisturizing qualities. Including extra fats in the mixture is known as superfatting.

Lye “Alternatives”
soap and oil bottles and wood table 151x151Still, some soapmakers make a point of positioning themselves as lye “alternatives,” insisting – for example – they use glycerin, instead, or make their soap without the involvement of lye. In both these cases, misinformation seems to be a factor. Glycerin is a natural result of saponification and the first step in creating bases for melt-and-pour soapmaking – the most convenient home-based process – is saponification.

Changing the Perceptions of Soap
Understanding chemistry can go a long way toward informing public perceptions, Our Soap Up Close - Close Formationincluding those of your customers. As negative as some perceptions of lye can be, all soap is made with lye – whether it’s bar or liquid – and soap made well can be great for your skin. The distinction between soap and commercial cleansers is especially clear with liquid soaps. Since most weren’t made with lye, what you’re buying isn’t soap, but a factory-made detergent for the skin.
Perceptions have their own momentum, and they can cause consumers to avoid products they might otherwise use. But perceptions can also be changed. Lye isn’t a villain, nor is soap made with lye something to avoid. In fact, in the hands of good soapmakers, it’s a product made with your skin and health in mind, and is far superior in overall quality and gentleness to commercial, non-soap cleansers. It’s what you should be using.

3 thoughts on “The Truth About Lye and Soap

  1. I’m not that much of a online reader to be honest but your blogs really nice, keep it up!
    I’ll go ahead and bookmark your website to
    come back down the road. All the best

  2. What do I need to put in my soap that will make it stay fresh longer. Is it a preservative? After a while my soap doesn’t smell as great. Still washes good!

    • Hi, Sharon – Thanks for the question. We definitely know what you mean. Natural soaps tend to lose color and scent over time. Although different recipes behave differently, we generally say that scent and color last 6-8 months. The soap itself is good for far longer. It’s all about oxidation. We use rosemary extract in our ready-to-ship blends as a natural preservative. We also offer Vitamin E oil in the Soapmaking Supplies on our website. Both are anti-oxidants and help stave off the loss of scent and color. Vitamin C can also be used, though we don’t use it ourselves very often. We’ve used it in custom soaps, but not enough to be certain of its effects. – Scott

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