Why Using Lye To Make Soap is Absolutely Important


  1. Why Do I Use Lye?
  2. Fun Facts about Soap Making 
  3. Tips for Those Wanting to Make Soap

When I first started researching soap making nearly 5 years ago I was initially concerned about using sodium hydroxide, or lye, as a chemical in my soaps. After all, why would I want to use an ingredient in my “all natural” products that is caustic and used to clean drains? Not only is lye dangerous if mishandled, the fumes it creates can literally take your breath away! That is why you always wear a mask and work in a well ventilated area when working with lye. 

1) Why Do I Use Lye?

Even after learning about all the possible dangers of handling sodium hydroxide, I still wanted to try my hand at making soap from scratch, so I did my research and bought safety gear. Then I watched a few more videos on how to properly handle lye (I highly recommend you watch these videos here and here), said a little prayer and made my first batch of soap. And guess what? I didn’t create an explosion and my first batches were actually soap (not the best but still not bad for my first few attempts). 

Why Use Lye in Soap?

Before I settled on using lye in my soaps I tried to see if I could make soap without it. You can make soap without commercial lye but it isn’t easy. If you do not use any commercial sodium hydroxide in bar soap making then you will have to try using older methods of soap making which take much more time. Commercial sodium hydroxide speeds up the saponification process, whereas older methods are much more complicated and tedious. Without commercial lye the process of cooking soap could take days, and quite frankly most of us don’t have time for that!

2) Fun Facts About Soap Making

The No Lye Myth?

Some people like to believe it is not necessary to use lye to make soap. While you may not need to use commercial sodium hydroxide to create a batch of soap, you still need a strong alkaline in order for the saponification process to occur. Even when soap was first created, they needed to use wood ash, which when filtered and boiled, creating the lye necessary to make the soap. 

What about when you buy a commercial bar of “soap” at the store? I don’t see any sodium hydroxide on the label? 

The fact is that “soap” you see at the store is really a detergent bar. These cosmetic, beauty, or cleansing bars, as they are now referred to, have harsh detergents such as sodium lauryl sulfate, to create the same bubbling effect that true soap has. The FDA more recently clarified the definition of soap. So now when you buy that Dove “soap” it is now referred to as a beauty bar, since it, by definition, is not true soap.

Fun Facts: 

  • The first records of soap making was over 4,000 years ago in 2,800 B.C., yet it was originally used for cleaning dishes and medicinal purposes, not for personal hygiene². 
  • Ancient peoples, including the Babylonians, used plant ashes to create the saponification reaction, yet it took much longer for the soap to cook and come together. 
  • Later forms of soap making utilized alkaline salts, such as limestone (sodium carbonate) and soda lime, to create the same effect as modern soap making. These alkaline salts still had the same challenges of modern soap making however, as they still are caustic and dangerous when mishandled.  

3) For those interested in making soap yourself, (you should it is so fun!) read these tips:

Warnings: How To Properly Handle Sodium Hydroxide

Lye, also known as caustic soda, if mishandled can cause burns to the eyes, skin, respiratory system, and digestive tract. When handling sodium hydroxide it is imperative to take the proper safety precautions.

Before handling lye put on protective goggles, disposable gloves, appropriate respirator (I use an R95 painters mask), long sleeved shirt and pants, closed-toed shoes, and pull back any loose hair or articles of clothing, and remove jewelry. Make sure to also work in a well ventilated room with no pets or young children in close proximity to your working area.

I feel like I am stepping back into high school and college science class when I make soap. I remember we weren’t allowed in the classroom on experiment days if we did not have the correct clothing. Make sure to enter your “experimenting” space with the correct gear!

Handling Tip: Another important and necessary step in making your own soap is to have separate materials to create your soap. Keep all soap making tools separate from food preparation tools.

Type of Utensils To Use/Not Use When Soap Making

Do not use metals when making soap unless it is stainless steel. Using aluminum when making soap is NEVER recommended as the metal reacts with the sodium hydroxide releasing more toxic fumes. An easy test to determine if a utensil or pot/container is aluminum or pure stainless steel is to use a magnet. A magnet will do nothing when it comes in contact with aluminum but will either stick to or repel(push away) from stainless steel. 

As well, try to avoid using wood and be wary of using glass due to the sharp temperature change created when first mixing the lye into water¹. I highly recommend not using glass for your lye-water mixture as the lye slowly etches away the glass and can cause the glass to shatter when the glass is heated!

Instead use high density polyethylene (HDPE) or polypropylene. HDPE has the plastic identification code number 2 and polypropylene has the plastic identification code number 5. (These are the numbers in the triangle made with arrows typically located on the bottom of the container) Lovin’ Soap has a great post about which containers to choose for soap making.

What if I Don’t Want to Handle Lye?

If you are not comfortable handling lye, purchase a soap base where the chemical reaction has already taken place. All you have to do to the soap base is melt it down and add extra ingredients. Personally I like having control over all aspects of my soap making so I use lye. I have used Our Earth’s Secret Honey Melt and Pour Soap Base base and their Raw African Black Soap when first starting to learn about soap making.

For those of you who are still unsure about using lye, that’s okay, but sodium hydroxide has been used in soap making since the early 1800s³ and people still use soap with no adverse reactions due to the saponification process (unless the lye was not correctly mixed). 

Where to Purchase Lye

If, after doing your research, you do choose to purchase sodium hydroxide and take the first steps into the wonderful world of soap making, you can purchase the same brand I use, Essential Depot, or you can see if your local hardware store has any in stock. I used to purchase Roebic 100% sodium hydroxide from Home Depot or Tractor Supply, but found Essential Depot was more cost effective for someone who will be making soap regularly. There are many different types of sodium hydroxide brands, just make sure whichever product you buy is 100% sodium hydroxide. You do not want any weird additives that may create an unwanted reaction when making soap.

Happy Soaping! 


  1. Lovin’ Soap
  2. SoapHistory.net
  3. Soapalooza!

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