What is Old-Fashioned Lye Soap?


It happens just like this:

The phone rings. A desperate caller asks,  “Do you have lye soap?”.

A sigh of relief meets my response.  “Yes, I have a few thousand bars.”

However, in my experience, it is necessary to probe further and educate when that question arises.

“Are you suffering from a particular skin condition?” I inquire.

The caller confirms she is battling skin irritations. Consequently, poison ivy scores high on the list with this type of inquiry.

Often those suffering with skin conditions search the net for answers.  Time and time again search results recommend the use of “lye soap” for poison ivy, eczema, psoriasis, and other itchy skin ailments. 

The search results read “get old fashioned lye soap just like grandma used to make.  It is the only thing that helps.”

Unfortunately, the average consumer is unfamiliar with the soap making process and with what constitutes old fashioned lye soap.  In fact, most don’t understand why handcrafted soap does not sport the label “lye soap”.

Today I want to give you a quick crash course on “lye soap” to clear up some confusion. I will answer several questions.

What exactly is lye soap?  Why do so many people recommend it for poison ivy? Why don’t companies label it “lye soap”?  Is it a lost art or a product unavailable to consumers today?

The answers to these questions start with the definition of soap.  The Food and Drug Administration defines soap by saying:

Ordinary soap is made by combining fats or oils and an alkali, such as lye. The fats and oils, which may be from animal, vegetable, or mineral sources, are degraded into free fatty acids, which then combine with the alkali to form crude soap. The lye reacts with the oils, turning what starts out as liquid into blocks of soap. When made properly, no lye remains in the finished product. In the past, people commonly made their own soap using animal fats and lye that had been extracted from wood ashes. 


What exactly is lye soap?  

It is made when lye is combined with an oil. The outcome is soap, real soap.  

Does it matter what kind of oil? 


Well, I take that back. Don’t use motor oil, of course. I have to explain that since we live in the age of Tik Tok challenges and Tide Pods. (And, for that matter, Google Translate, which has been known to render “oil” as “petrol” instead of “aceite” when translating English to Spanish.)

Homesteaders of old used what they had readily available.  Often it was tallow or lard. Sometimes it was even bear grease or venison fat. 

Today many soap makers use a combination of oils. 


Each oil creates a different property in the soap.  Some oils, like castor. create amazing bubbles.  Other oils like coconut and lard make a hard bar.  Olive oil makes a softer conditioning bar with few bubbles.  Combine a variety of oils and voilà, you get an incredible diversity of soap in the market place. Artisans alter their formulas to create soap that satisfies their customer base.

Handmade soaps today use the same process as the old-fashioned lye soap, with a few ingredient differences.  The most notable differences are in the wide variety of oils available to soap makers today.  Homesteaders were generally limited to tallow and lard.  Today the options are endless. Further, we are not limited to the use of rain water as a liquid. Soap makers use milk, beer, wine, coffee, kombucha, and more.

The other significant difference is that lye used back then was hard to standardize. It was created using the crude method of running water through wood ash then through a filtration system.  The result was potassium hydroxide which made a softer soap.  Homesteaders struggled to create a balanced formula because of the absence of precise scales.  Sometimes the soap was lye heavy (a term used to indicate there is lye left over in the final product). It would strip the skin leaving it dry and irritated.   

Modern soap makers have the benefit of using standardized lye. We generally use the form of lye called sodium hydroxide.  Likewise, potassium hydroxide lye used in softer soaps must now meet standards for purity and strength. This gives the modern soap maker more control over the final product. The handcrafted soap industry takes an old art and modernizes it with the benefits of science and technology to provide a luxury skin care option.

Why is old-fashioned lye soap the soap of choice for skin conditions like poison ivy?

Poison ivy plants produce oils that adhere to the skin.  Old fashioned soaps that were astringent (stripping or drying) in nature removed this oily residue. However, the drying nature of the soap led to secondary issues of itchiness and rash because of improperly balanced formulas.

In working with older clientele, we have found some had a strong aversion to handmade soap because of bad experiences with their grandmother’s soap.  After some education about the reasons for the harsh soap, they had a more satisfying experience and became loyal customers. 

The best thing to do when exposed to poison ivy is to wash with warm, soapy water as soon as possible to remove the plant oils. It is important to avoid using a poorly formulated soap for the reasons cited above.  Keep in mind the soap making industry has a low entry point.  Not all handmade soaps equal high quality. Finding a properly formulated soap is important when washing sensitive skin. 

Why don’t companies label their soap as “Lye soap”?

Some companies do label their soap as Old Fashioned Lye Soap. However, labeling a soap as “lye soap” is technically incorrect. Remember the FDA definition?

When made properly, no lye remains in the finished product.

As a result, some soap makers do not use the word lye or sodium hydroxide on the label.  Yet it is soap made the same way homesteaders made it, though with modern practices like stick mixers, calibrated scales, and standardized lye.

Yes,  all real soap begins with lye.  However, the soap making process involves an intriguing chemical transformation of raw materials.  Scientists call this process saponification.  It is a chemical process that changes the raw ingredients from their original state.

Members of the handcrafted industry hotly debate labeling requirements.  Since the FDA and the Consumer Product Safety Commission have no enforceable labeling requirements for soap, labels may vary from company to company.  Many soap makers choose to use the words “saponified oils of” because it reflects more accurately the ingredients in the final product. We chose to label our soaps with the words “saponified oils of …”


First, labeling it with the words “lye or sodium hydroxide” is technically incorrect. These components change via chemical processes.  Second, it is common knowledge that lye as a raw ingredient is caustic.  Without a working knowledge of the soap making process, some consumers wrongly conclude that lye remains in the final product and that handcrafted soap is caustic.  They fear using a product containing “lye” in the labeled ingredients.  Again, it is important to note here that properly formulated soap will not have any lye in the final product.  More importantly, our formula has stood the test of time offering our customers satisfying results for over 15 years.

So why use handcrafted soap for sensitive skin?

Properly formulated, handmade soaps contain all the natural components of the soap making process.  Including glycerin, which makes these soaps less harsh and less drying. However, many large manufacturers remove the glycerin from soap, to use it in high-end lotions.  This, together with the artificial dyes and chemicals found in most commercial body bars or liquid soaps, tends to irritate the skin. Which makes natural soaps a great alternative for those suffering from skin conditions. Many artisans focus on quality ingredients and fragrances, keeping irritants to a minimum, or removing them altogether.  Customers can bathe without worrying about harsh or skin-drying chemicals. Also, this is a plus for people who have sensitive skin or allergies.

With these things in mind, let’s recall the earlier question:

What exactly is lye soap?  Is it a lost art or a product unavailable to consumers today?

The good news is: The fundamental chemical process of soap-making remains the same. The modern improvements of precise weight measurements and standardized ingredients make the outcome far superior to Grandma’s version. As a result, “Old-fashioned lye soap” is available in this new and improved version. Bright Hope Soap Works offers an unscented soap called Simplicity for those who are suffering from skin conditions. It contains no colorant or fragrances. It is a great place to start when struggling with skin irritations. Like poison ivy.

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One Comment

  1. This is exactly why I started purchasing soap from Christina at Bright Hope Soap Works. The result of less skin irritations, no chemicals, and beautiful soaps is why I come back time after time. I will never purchase soap from box stores again. Thank you for a wonderful product.

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