It is critical to follow a few simple safety precautions when using lye for soap. Proper ventilation, along with gloves and eye protection, will help to prevent any kitchen mishaps from turning into injuries.

People all over the world have been making soap for centuries. This included knowing how to make Castile soap, originally made from pure olive oil. The origins of Castile soap go back to ancient Aleppo, where soaps have been made from olive oil and laurel oil for millennia. Today, soap makers have the benefits of modern chemical factories, which produce lye for soap at a constant alkalinity level, allowing the maker to create soaps precisely as strong or mild as needed.

Can soap be made without lye? Not really. Soap is comprised of fatty acids plus sodium hydroxide. More basically, soap is oil plus lye. It is impossible to make soap from scratch without lye. Melt-and-pour, glycerin soap bases are pre-made soap, where the lye has been processed for you.

Workspaces and Equipment

Before making soap in a kitchen, be sure to remove all food and appliances from the area. Consider covering your work area with paper towels, newspaper or a plastic tablecloth to catch loose lye or drops of caustic soap. Any work area you use should have access to running water for safety. Keep walkways clear.

Always secure pets so they don’t interrupt soap making, and for the same reason, have someone watch the children or wait until they are napping. Do not make soap when there is a good chance of interruption, because once lye and oil are mixed together, you need to be present and focused until the process is complete.

Making soap from scratch requires additional gear to protect from chemical burns. Long sleeves are a good idea, and always be sure to wear gloves. Eye protection such as safety glasses or goggles to protect your vision from damage from lye splashes. Some soap makers wear gas masks or wrap bandanas over their faces when they add lye to water since it creates caustic steam for a few minutes. Others combine the ingredients beneath a fan or outside. Just make sure you have proper breathing protection or proper ventilation.

Before saponification, lye can react with aluminum and cause a surge of heat that can melt some plastics. Glass is the most nonreactive material, but it is heavy, is slippery and can sometimes break under the stress of sudden temperature changes. The best materials are a mixing pot that is either plastic, stainless steel, or covered with enamel. Whisks and immersion blenders made of stainless steel, silicon spatulas, plastic spoons, pitchers made of dishwasher-safe plastic, and molds made of approved plastic or silicon are also very useful cold process soap supplies. Be sure to keep separate bowls and utensils for soap making only — you don’t want to risk contaminating your food.

Many different oils can be made into soap, but each requires a different amount of lye to saponify one gram of oil. Always check your recipe with a soap calculator prior to starting each batch. Research how to add products like honey and goat milk to avoid burning. Some of the best soap-making resources available are online forums where experienced crafters share safety tips with newcomers.

The Soap Making Process

Always measure lye for soap, water, and oils by weight instead of volume. When learning how to make homemade soap, people often want recipes measured by volume because they don’t own scales. Purchase a scale with at least 2 decimal places for best accuracy. It’s the only way to ensure you have the correct chemical balance.

Select containers deep enough to contain all the water, oils, and lye while avoiding spills and splashes. Always add dry lye to the water; never add water to the lye. Pouring water onto the lye can result in caustic splashes. Allow the lye water to cool to desired temperature, or at minimum, allow the solution a few moments to clarify so you can see if any lye remains unmixed. Carefully pour the lye/water mixture into the oils. Avoid splashing as you mix the liquid and add colorants and fragrance. As you pour the liquid soap into molds, be careful to avoid spilling.

During active saponification, your soap mixture may heat up and resemble petroleum jelly in the center of the mold. For this reason, you should always use molds that can withstand significant heat. Certain additives, such as honey or pumice, can increase the heat. You can usually avoid gelling, if you wish, by immediately placing the molded soap in a refrigerator or freezer. This will not stop the saponification process, although it will slow it down somewhat. After 24 hours the soap can be removed and cured normally. If the soap begins to gel in the mold anyway, you can simply insulate the mold with towels and allow it to reach full gel stage all the way through. If needed, an oven set to between 150-170 degrees Fahrenheit can encourage the process along.

Lye can splash, and soap molds can tip over. Crafters stumble and pots fall. If you spill lye or raw soap, remain calm. Lye quickly washes off beneath running water and won’t burn skin unless you let it sit or it gets in your eyes. Do not try to neutralize with vinegar or other acids, because adding acid to alkali can create a caustic volcano effect. Rinse off the skin immediately, until the slippery feeling goes away. Always wear eye protection. Wipe up spills with a clean towel then immediately place the towel in the washing machine. A little lye or raw soap can be good for the laundry. Keep surfaces covered so spills go right into the garbage or are easily wiped clean.

Curing and Storage

Purchasing litmus paper strips from the local pharmacy is the easiest and most accurate way to test your fresh soap for alkalinity. However, some people prefer to use the old-fashioned “zap” method, where they touch their tongues to the soap. If they do not feel a sharp sensation resembling electric shock, the soap is safe.

If you find dry, white pockets in your soap, set it aside to be rebatched at your convenience. There is no need to waste soap — it can almost always be fixed through rebatching soap.

Because soap is made with oil, it has the potential to go rancid. Some recipes go bad faster than others. Large amounts of soybean or canola oils are prone to create the dreaded orange spots of rancidity. To avoid this, cure the bars by placing them in a cool, dry location with plenty of air flow for six weeks or longer. This makes soap milder and longer-lasting. However, if your soaps do develop the orange spots, do not worry — it is still safe to use the soap.

Soap can last months to years, and a lot depends on proper storage. Do not enclose soap in an airtight container or covering for storage. Airflow is key to avoiding rancidity. Experienced soap makers wrap bars in paper or store in cardboard boxes, divided with paper towels. Do not store extra bars in your bathroom because the heat and moisture reduce shelf life. The best place is in the closet or a dry basement.

With a few simple precautions, making soap can be a fun and efficient way to create soap products ranging from the practical to the luxurious. Do your research before you begin, always read your recipes carefully, and enjoy!

Melanie Teegarden is a longtime professional soapmaker. She markets her products on Facebook and her Althaea Soaps website.