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How to Handle Lye Safely

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By Jan Berry | Jun 11, 2018

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Like other household chemicals, lye can be dangerous if handled improperly, but you will rarely encounter issues if you work in a thoughtful and careful manner.
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“Simple & Natural Soapmaking” by Jan Berry offers everything the modern-day enthusiast needs to make incredible botanical soaps.
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    Simple & Natural Soapmaking(Page Steet Publishing, 2017)by Jan Berry presents 50 easy, unique soap recipes with ingredients and scents inspired by the herb garden, veggie garden, farm, forest and more. Beginners can join in the sudsy fun with detailed tutorials and step-by-step photographs for making traditional cold-process soap and the more modern hot-process method with a slow cooker. This section explains why lye is necessary to make soap, and how to use it safely.

    A few generations ago, our great-great–grandmothers made their own lye, called potash, using wood ashes and water. They combined this highly caustic substance with fat rendered from butchered animals and boiled the mixture over an outdoor fire for many hours until a soft soap was formed. While this resulted in a truly natural soap, it was also difficult to control the quality of the final product.

    These days, we have manufactured substitutes to replace that wood-ash solution. Sodium hydroxide, also called caustic soda or lye, is used to create solid bars of soap, while potassium hydroxide is used to make liquid soaps. With these standardized ingredients, the guesswork has been removed and modern soapmakers can reliably produce batch after batch of gentle, balanced soap.

    Many crafty types find themselves interested in making their own soaps, but are concerned about handling lye. They often wonder if it?s possible to make soap without it.

    The short answer to this question is no. By definition, soap is what you end up with when fats and oils are combined with a highly caustic solution, no matter if it?s our great-grandmother’s potash or our modern-day sodium hydroxide.

    When lye meets oils and fats, a chemical reaction occurs that changes both substances. Once that reaction is complete, you no longer have oils or lye; you’ve created soap! If made correctly, no lye is left in the final product. It?s all used up and transformed on a molecular level during the process of converting the oils into soap.

    By checking the label of your favorite store-bought soaps, you’ll see that most are made using this method as well. You’re likely to find words like sodium cocoate or sodium tallowate in the ingredient list. Those are just fancy ways of describing coconut oil or tallow (animal fat) that has reacted with sodium hydroxide (lye). Sometimes, labels may list ingredients such as saponified coconut oil or saponified olive oil. Saponified is another way to describe oils or fats that have been turned into soap after being exposed to lye.

    If your favorite commercially produced soap doesn’t list anything like that on the label, then it?s likely made with one or more lather-producing synthetic detergents, such as sodium laureth sulfate or sodium lauryl sulfate, instead.

    Lye Safety Tips

    If you decide to venture into soapmaking, follow standard safety precautions to help reduce the risk of serious harm. Like other household chemicals, lye can be dangerous if handled improperly, but you will rarely encounter issues if you work in a thoughtful and careful manner.

    Lye should be used only by responsible adults. Never use it around children or pets.

    Wear safety goggles, long sleeves and gloves during soapmaking sessions. Lye solution and fresh soap batter can cause serious damage to your eyes and painful burns on your skin. If this happens, rinse repeatedly with generous amounts of cold water for several minutes. Seek medical attention promptly for eye contact and large burns.

    Sodium hydroxide is available in pellets, granules or flakes. All work equally well to make soap, though extra care is needed when working with flakes, as they tend to emit powder into the air that can be breathed in, irritating the lungs more easily. If dry lye spills on a surface in your work area, carefully brush off as much as you can, then wipe over the area with a damp cloth several times.

    Always pour lye slowly into water that’s room temperature or colder. By adding water to dry lye or pouring lye into hot water you risk overheating and producing a volcano effect. For this reason, it?s a good idea to mix the lye solution in your kitchen sink. If any accidents occur, they will be contained and much easier to clean up than a countertop spill.

    Avoid breathing in fumes. When lye is first mixed with water, it will form strong fumes. Work in a well-ventilated area such as outdoors, in front of a window or under an exhaust fan. Turn your head away as you stir. If you find yourself sensitive to the fumes, consider wearing a respirator. Clearly label containers intended for mixing and holding lye solution with a skull and crossbones symbol, and when filled, place in a safe location out of reach of children and pets. By doing this, even non-readers will realize the contents should not be handled or ingested. Just like bleach and other strong household chemicals, lye can be fatal if accidentally swallowed.

    Use the proper equipment. Never use aluminum when making soap, as it will combine with lye to form a toxic reaction. Mix your lye solution in a heavy-duty heatproof plastic container (look for recycle symbol number 5 on the bottom) or stainless steel, as glass has the potential to shatter. Stir the lye solution with a heavy-duty silicone or heatproof plastic spatula or spoon. Have separate equipment for measuring and mixing lye and do not reuse them for food preparation.

    Remember that these are worst-case scenarios. Soap is made every day by people all over the world without incident. Caution when handling is wise and necessary, but don’t allow fear to keep you from trying out a rewarding new pastime.

    Lye Calculators

    An important tool for soapmakers, lye calculators are used to determine the exact amount of lye needed to create a balanced bar of soap.

    Oils and fats are unique in their individual makeup and require differing amounts of lye (sodium hydroxide) to turn into soap. For example, olive oil requires roughly twice as much lye to saponify (turn into soap) than jojoba oil. If you decided to replace the olive oil in a recipe with jojoba instead and didn’t change the lye amount, you may end up with too much lye.

    There are several lye calculators available to use for free online and while they vary somewhat in their layout and appearance, they all return reliable results, as far as how much lye you need for the amount of oils in a recipe. You can find a listing of online lye calculators in the resource section in the back of this book.

    My preference is to use the one found at www.TheSage.com for its straightforward simplicity, so that’s the one I refer to in the instructions below.

    How to Check a Soap Recipe with a Lye Calculator

    All new-to-you soap recipes, even ones in this book, should be double-checked with a lye calculator before making. Typing and printing errors happen, so taking a quick minute to make sure the recipe is correct will be time well spent.

    1. Go to www.TheSage.com (my preferred online lye calculator) and click on the link that says Lye Calculator. You’ll be presented with a form to fill in.
    2. Select whether you want to work in ounces or grams, double check that the lye type is sodium Hydroxide (NaOH), which is the type of lye needed to make solid bars of soap, then scroll down to the big list of oils.
    3. Input the oils listed in the recipe that you’re interested in making. As an example, if the recipe requires 15 ounces (425 g) of olive oil and 5 ounces (142 g) of coconut oil, and you’re working in ounces, then input the number 15 inside the box beside olive oil and the number 5 inside the box beside coconut oil. Scroll to the bottom and click the Calculate Lye button.
    4. A new screen will appear with the results, which break down in the following way.
    5. In the Liquids box, the calculator gives a range of liquid to use in your recipe. For our example recipe from step 3, it tells us we need approximately 5 to 8 ounces (142 to 227 g) of liquid. If you use the lower number, your soap will reach trace and set up in the mold more quickly than usual. Sometimes, this is a good thing, such as when making castile soap; other times, the soap batter will move too rapidly to easily work with. The lower range is not recommended for beginners. The higher end of the water range, in this case 8 ounces (227 g), will give you plenty of time for swirls or more intricate details, but will also take longer to reach trace and firm up in soap molds, plus may need a slightly longer cure time to permit excess water to evaporate. The middle of the range, in this case 6.5 ounces (185 g), is a happy medium that should give good results. An even easier way to determine water amount for your recipe is by employing a handy tip learned from Amanda Aaron of the Lovin Soap website and just use twice as much water as lye.
    6. Beside the Liquids box, you’ll see a Fats & Oils section that breaks down your recipe’s oils into percentages. While those guidelines are suggestions only and shouldn’t be taken as gospel, if you see a recipe requiring 85 percent jojoba oil, you’ll know there might be an error somewhere.
    7. Right beside Fats & Oils is a lye table. In most cases, you want the lye amount to fall in the 5 to 8 percent range.

    Once you’ve verified that the recipe you’re interested in has a safe amount of lye, you’re ready to make your soap.

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    Excerpted from Simple & Natural Soapmakingby Jan Berry. Copyright © 2017 (Page Street Publishing. Used by permission of the publisher.

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