When making soap from scratch, there’s one thing you just can’t avoid: lye. Without lye, your soap just isn’t soap! Working with lye may seem daunting at first, but if you learn proper handling techniques, take precautions and follow basic safety guidelines, there is no reason to fear it. You may be familiar with Sodium Hydroxide, which is used to make solid cold process soap, but today we’ll cover Potassium Hydroxide, which is used exclusively in liquid soap.  Although the rules for working with Potassium Hydroxide are similar to working with Sodium Hydroxide, it is important to understand and recognize the differences. Plus, it’s always nice to have a general lye safety refresher! To learn more on general lye safety, check out this blog post.

Potassium Hydroxide is a type of lye specifically used to make liquid soap. It is also known as potash, lye or even KOH. This is the chemical that induces saponification of the fats and oils to create liquid soap. Even though making liquid soap is different than making bar soap, it’s still vitally important that you use the correct amount of lye in your recipe. Our lye calculator makes this easy and allows you to select liquid soap as an option.

Potassium Hydroxide is hygroscopic (meaning it attracts moisture), so be sure to keep it in a sealed container in a cool dry place. If you leave it in an open container for even a day, it can attract enough moisture to throw off its weight enough to ruin a recipe.  If you leave it out for an extended period of time, it can attract enough moisture from the air in the room to turn completely liquid. When handling Potassium Hydroxide, give it the same safety considerations as you would with Sodium Hydroxide. It is a hazardous material, and being educated about safe handling practices is key when handling Potassium Hydroxide. As with any other type of lye, Potassium Hydroxide will emit some fumes, so be sure to soap in a well-ventilated area.

Always add your lye to your water, and never the other way around. Adding water to lye can cause a volcano-like reaction. Unlike Sodium Hydroxide, Potassium Hydroxide reacting with water makes a faint crackling or groaning sound — a somewhat subtle version of adding milk to Rice Krispies cereal.

When working with lye water, wear goggles that protect your eyes from all sides because alkali burns can cause blindness. If you wear glasses, check your local hardware store for goggles that are big enough to fit over them. Always wear an apron and gloves. Rubber dish gloves are great, but if they’re too bulky you can use thinner latex gloves.  Pair your gloves with long sleeves because the less exposed skin you have, the better. Finally, use a heat safe container to hold your lye water, and use silicone or stainless steel tools to stir (no wood). Never use any tools or bowls containing aluminum as that will create highly flammable hydrogen gases. Remember that when Potassium Hydroxide is mixed with water, it produces a reaction that heats the water up substantially, making it all the more important to mix lye in a heat safe container.

Never leave your lye water (or lye) unattended or in an place where children or pets may come in contact with it. It only takes a few seconds for an accident to happen! If you do need to leave the lye unattended for whatever reason, cover the container with a piece of plastic wrap and use a sticky note to clearly label it as a hazard.

If there is an accident:

If swallowed: Rinse mouth with water and drink one or two class of water. Do not induce vomiting! Immediately get medical attention or call your poison control center at 1-800-222-1222.

If in eyes: Immediately flush eyes with water. Remove any contact lenses and continue to flush eyes with water for at least 20 minutes. Immediately get medical attention or call your poison control center at 1-800-222-1222.

Lye water on skin: Wipe solution from skin and remove any contaminated clothing. Flush skin with plenty of water for at least 15 minutes and then wash thoroughly with soap and water. Contact a physician or call your poison control center at 1-800-222-1222.

Raw soap on skin: Even after it has been mixed with oils, lye can still be dangerous. If exposed skin comes in contact with raw soap batter, flush with water for 5 minutes and then wash thoroughly with soap and water.

Just like any tool, Potassium Hydroxide can be used safely and carefully to create wonderful liquid soaps for personal or business use. Use it responsibly.

What are you experiences working with Potassium Hydroxide? Let us know your best tips and tricks to work with it in the comments below!