Working With Lye: Definition and Safety Precautions

What is lye?

When dealing with lye to make fresh soap, it is EXTREMELY important to practice caution. Although soap making is a great and fulfilling hobby, it is also dangerous if the proper precautions are not taken. Please read the following for safe tips and practices when you are dealing with lye.

Lye, or caustic soda, comes in two forms. These are known as sodium hydroxide (soda lye) or potassium hydroxide (potash lye). Each are used in soaps, but for different applications. Sodium hydroxide is most commonly used. You will get sodium hydroxide to make any bar or hard soaps. Potassium hydroxide is used for cream soaps, liquid soaps, and other soft soaps.

When making soap, lye is basically dispersed in cold water and then mixed with an amount of heated fats and oils. When the lye water and oils come together to make soap, the process is called saponification. Once saponification occurs completely, it is safe to use soap on your skin. However, many soap makers, especially cold process soap makers, prefer to let their bars of soap sit in the air and "cure" for a few days up to a few weeks so it can harden (lose its extra water weight) and become milder to the skin.

Where do I find lye?

Lye can be found in many places if you look. One of the more common over the counter uses is for drain openers. HOWEVER, most drain openers that contain lye ALSO contain other materials which are harmful if used in soap, such as metal shavings. You must not only look on the ingredient label, but also look at the product MSDS sheet. Sometimes when labels say 100% lye, they aren't actually. One sure product is Roebic's Heavy Duty Drain Opener. This is what many people use, and it IS 100% pure sodium hydroxide, which is needed. One place that sells this is Lowes.

Lye is slowly becoming harder to locate, however, because of increasing laws restricting it's sale to minors who use it for "less productive" activities. Because lye is often used in the process of creating drugs, many stores elect to either not sell lye, or keep it behind a counter until it is requested. So, if you don't see it in your store, ask a manager. They may have it, but not on the shelves.

If you do not have a store nearby that sells lye, another great way to get it is online. There are many great lye retailers where you may purchase small and bulk quantities for a reasonable price. You can find lye at most soap supply stores, and we have a few links to stores that sell lye online in our link exchange section.

Lye Caution

Before lye is saponified with fats and oils, it is extremely harmful to the body, even when mixed with water. If it is inhaled, touches the skin, or enters the mouth, contact a poison control center immediately. When lye comes in contact with the body, it can leave severe burns. Lye is caustic, which means burning or corrosive. In other words, it will keep burning and eating away at materials that do not have a resistance to lye. Making soap is an extremely enjoyable hobby if the proper precautions are taken.

Along with following the instructions for use on your MSDS sheet included with your lye, please follow the following guidelines to make soap safely.

• Always wear long sleeve shirts to cover your arms in case of spills.
• Always wear rubber gloves and goggles to protect your eyes.
• When lye is mixed with water, it releases potentially toxic fumes. Make sure to mix your lye and water in a ventilated area (even outside is good) and wear a mask over your nose and mouth. Masks can be picked up at Wal-Mart in the hardware section for about two dollars for a pack of 3.
• When disposing of lye, do it in a safe way according to instructions on the packaging.
• NEVER pour water into lye. This has a huge potential to cause a volcano effect. ALWAYS pour lye into cool/cold water while mixing thoroughly. In addition, lye water will become HOT, almost to the point of boiling, so take care not to get burned.
• Lye will eat through aluminum, tin, zinc, non stick coating on pans, etc. When making your soap, the only safe things to mix in are glass, stainless steel, or heat resistant plastic. This includes your mixing bowl, mixing spoons, molds, etc.
• When storing lye, make sure the container is air tight and out of the reach of children and pets. When air contacts lye for a period of time, the lye draws the moisture out of the air. This can make the lye form hard lumps, and also become less potent when making soap.
• When making soap, keep a bottle of vinegar handy to pour on skin in case it comes in contact with the lye. Vinegar helps to neutralize the effects of lye. This does NOT mean you shouldn't seek medical care, however.