Sodium Hydroxide

Sodium Hydroxide (NaOH), also known as lye, is an essential ingredient in the soap making process. When sodium hydroxide beads or flakes are mixed with a liquid,  a lye solution is created.

This solution, when mixed with fats and oils, will cause a chemical reaction called saponification. The result of saponification is beautiful handmade soap.

Soap making is a wonderfully fun and addictive craft but as with many things that are fun, it is not without it's risks. Lye is a caustic substance that must be handled with great care. Give it the respect it deserves.

Just as you would use caution with moving pots of boiling water around in the kitchen, so must you with lye.

Sodium Hydroxide (lye) Safety Information for Soap Making

Please bear in mind, this page is not meant to frighten you away from ever making soap.

It is however, meant to give you a greater understanding of the caution and attention that must be given when handling this chemical.

I started making soap when both my children were still in diaper's and we had a dog as well as a cat.

Careful planning makes everything run smoothly and has helped me avoid having any accidents.

*NOTE - Potassium Hydroxide (KOH), used in liquid and soft soap making, is just as caustic and it is advised that you practice the following precautions when using it as well.

1. Plan to make your soap during a time when you won't be interrupted.

2. Make sure pets and children won't be in the general area and get underfoot. You don't want to be startled by the silent, stealthy approach of a curious mind while mixing up a lye solution.

3. Have a water source nearby in case you need to quickly wash off any spills.

4. Mix the lye in a well ventilated area (opening some doors or windows is usually sufficient) and make the soap in the same place so you're not transporting the liquid lye around and increasing the chance of spills.

5. Wear goggles, rubber gloves, long sleeved shirts and pants when using lye.

Sodium hydroxide can cause blindness if it gets into your eyes and burns if splashed on your skin.

Any spills on your skin and eyes should be flushed with water for 30 minutes.

Large spills and exposure to eyes will also require medical attention after flushing with water.

Be sure to read the Medical Safety Data Sheet that comes with your lye or request one from your supplier.

Do not under any circumstance swallow lye as this could be fatal! Keep locked away from pets and children. Swallowing lye will require immediate medical attention. 

Assuming you're still here reading this and haven't run screaming in the other direction, lye can be purchased in pellet or flake form at soap supply stores, chemical supply houses and hardware stores.

Hardware stores will have it near the drain cleaners. Do not confuse lye with Drano. Drano contains substances you would not want to put in soap.

Special Note: Always add the lye to the water and NOT the water to the lye. An unpleasant, violent reaction occurs if you do. Kind of like vinegar and baking soda is my understanding.

Here are a few links to some websites that carry Sodium Hydroxide. If you know of others, please let me know using the contact form.


United States

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› Sodium Hydroxide

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