How to make soap at home (even if you failed chemistry)

Lessons in lye

Published July 15, 2022 3:29PM (EDT)

 (James Ransom / Food52)
(James Ransom / Food52)

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My experimentations with homemade soap began when I became enamored with making things at home, like maintaining my own sourdough starterpainting my own kitchen cabinets, and repairing my own clothes. Even if time-consuming, I found that doing things myself, from start to finish, was immensely rewarding. It gave me a far greater appreciation for the goods that came my way, and made me a lot more conscious (in a good way) of the quality of ingredients. 

As time went by and my life got busier, my hobbies went on the backburner. However, soapmaking stuck around. It was very complicated at first, and therefore can be off-putting to some, but I've actually found it has one of the best effort-to-reward ratios out of all my hobbies. Much like knitting, it's a meditative activity and a creative outlet. But unlike knitting, just a few evenings or weekends of work can reap great rewards, as well as furnish me with loads of ready-made gifts for the people I love.

With just some tools (many of which are old friends in the kitchen), and armed with an understanding of how it all comes together, homemade soap really doesn't feel that much more ambitious than some of the more adventurous baking projects I've embarked on over the years, like baking bread — and the results are well worth it. Much like freshly baked goodies, they can also fill your home with delicious scents. Once you have a base recipe down, you can also play with shapes, colors, scents, and additives to customize each batch, and make them your own. 

Here's how you can make homemade soap.

What you'll need:

16 ounces coconut oil 
14 ounces palm oil, preferably from a responsible source (alternatives to palm oil can be found here.)
21 ounces olive oil, any you can find
19 ounces distilled water
sodium hydroxide (lye), a 2 pound container of which will make about 4 batches of soap
7 teaspoons essential oil or fragrance oil (optional)

Large heat-safe vessel such as an enamelware soup pot*
Measuring cup or small bowl*
Heat-safe vessel, ideally with a handle, such as a heavy glass pitcher*
Silicone spatula or other stirring utensil*
Instant-read thermometer*
Immersion blender*
Scale that can measure in grams and ounces
Soap mold or a 9-inch by 13-inch baking pan*
Plastic wrap (if using a baking pan)
Waxed paper or parchment paper
Teaspoon and additional measuring cup (if using fragrance)
Old towel or blanket
Sharp, thin knife
Rubber gloves
Safety goggles

*Any tools that touch lye should NOT be reused for cooking!

Notes on safety, lye, and sourcing tools:

Although the process of making soap is by and large simple and safe, it is necessary to practice caution during the process that involves handling lye. Lye is a caustic salt (also refered to as sodium hydroxide) that mostly comes in crystalline form and if handled incorrectly, can burn skin and eyes. To protect yourself, remember to always wear gloves, eye protection, and long sleeves, and work in a well-ventilated area like a garage or your driveway. Keep your face away from the lye as you mix it, and keep pets and children away as it's cooling. But don't worry about your soap being unsafe — all the lye will be used up in the saponification process (the reaction between lye and fat that makes soap and renders the lye safe to handle) and none will remain in the finished product.

If you're at all concerned about working with lye, an easy way to ensure none remains in your finished soap is to use a little more fat than the amount listed so it's cancelled out by the saponification process. This is called "superfatting," and will almost definitely be covered in any calculator, chart, or other resource used for developing soap recipes.

For soapmaking, I recommend purchasing lye marked as "pure" or "food-grade," and shop onlinerather than in stores. I don't recommend buying lye that's specifically marketed as a drain opener (its other primary use) for this process because it might have other ingredients as well. It comes in different forms like little beads or flakes; it doesn't matter which you choose for this process. (Interestingly, lye is also used in some recipes. I've haven't done it yet, but I've been wanting to try making these Bavarian-style soft pretzels.)

Although soapmaking becomes cost-effective if you do it often, making your first batch can seem like a bit of an investment since none of the tools can be reused for cooking (a good reason to make soap again and again). I've linked above to budget-friendly options for many of the tools required, but thrift stores are also a great option for items like the pitcher and pot. Oils for soapmaking can be purchased in 7-pound bags, which will keep costs down if you're making more than one batch.

How to make soap at home:

1. Mix the lye. Put on your rubber gloves and safety goggles, and set up in a very well-ventilated area such as next to an open window. If you have access to a garage, driveway, patio, or balcony, head out there. Use your scale and measuring cup to carefully weigh 201 grams of sodium hydroxide and set it aside. Then, weigh 19 ounces of distilled water into your glass pitcher or other sturdy, heat-safe vessel. Now, carefully pour the sodium hydroxide into the pitcher of water, and stir just long enough to make sure it all dissolves. This creates a chemical reaction that heats the water to over 200° F and produces strong fumes at first, so work quickly and be extra careful here — I try to hold my breath while I stir. (Safety note: Always work in this order and add lye to water. Never add water to lye, which can cause spattering of the hot lye solution or even an explosion.)

The lye now needs to cool to below 100° F. I usually place mine outside on my porch to speed up this process. Depending on how cold it is out, it can take between 30 and 90 minutes for the lye to cool, which is why I recommend getting this step out of the way first. 

2. Prepare the mold and measure out fragrance. If you're using a wooden loaf mold or a baking pan, carefully line the inside with waxed paper or parchment paper so its easier to get the soap out later. I often use some masking tape to help hold everything in place. If you use a silicone mold, you can skip this step.

If you like the simplicity of plain rectangular soap bars and think you'll make more than a couple batches of soap, having a wooden loaf mold like the one shown here makes the process easy and consistent. (I've found eBay and Etsy to be good sources for wooden versions at lower prices.) Other options include silicone and PVC plastic molds, which come in many shapes and patterns. If you're not ready to invest yet, a 9 by 12-inch baking pan or Pyrex dish that you're willing to part with isjust fine. 

Now is also a good time to measure out your essential oils into an extra measuring cup, for ease of adding them later. Blending fragrances is probably one of the most fun parts of making soap. For this batch, I used 5 teaspoons of orange essential oil and 2 of sandalwood. Synthetic fragrance oils also work well and are generally less expensive than pure essential oils. Mixing fragrances is akin to mixing spices and other ingredients when experimenting with cooking a dish — here is a great set of tips for having fun with blending fragrance oils. You can also opt to make unscented soap if you're very sensitive to scents and perfumes.

3. Melt and mix the oils. You can now prepare the blend of oils to which you'll add the lye. If you're using oils that are solid at room temperature, such as the coconut and palm oils in this recipe, you'll first need to melt them so they can be poured, either by placing the container in a saucepan of simmering water or by melting them in the microwave.

Once your oils are in a liquid state, place your large pot on the scale and weigh (or re-weigh, if you've already done so) each oil into it for precision. Stir everything together and then check the temperature with a heat-safe thermometer. For the next step, the oils need to be between 80 and 100° F. I often find that mine are already in the correct range from being melted, but if not, place the pot on the stove over low heat until the oils reach the proper temperature or set aside to cool down.  

4. Blend and pour your soap. When both your lye and your oil mixture are between 80 and 100° F, you're ready to blend. After removing the pot from the heat to a trivet or heat-safe surface, put your gloves and eye protection back on, and carefully pour the lye into the pot of oil. They'll begin to react with each other, turning the mixture cloudy. Begin blending with your immersion blender, and over the next 3 to 5 minutes you'll see the mixture become thicker and more opaque. You're aiming for a mixture with the consistency of a runny pudding. If you lift the blender out and let some drips fall across the surface of the mixture, you should see them leave a visible pattern, called "trace," before sinking back in.

Once the soap mixture has reached trace, stir in the fragrance oil, if using, until blended. Carefully pour the finished mixture into your lined soap mold, and cover with the lid (or plastic wrap, if your mold has no lid). Being sure to keep it level, wrap the whole thing in a towel or blanket to insulate it, and leave undisturbed in a well-ventilated area that's out of the way for kids and pets for 24 hours. 

This method that I use for making soap is called cold process, where no additional heat is used to facilitate or speed up the saponification process. Hot process, on the other hand, uses an external heat source to accelerate it. While cold process soaps take longer to cure (the next stage, below), the choice to use one or the other is entirely personal.

6. Cut and cure your soap. When your clock indicates that 24 hours is done (don't try and rush it), your soap is ready to be removed; many wooden loaf molds have fold-down sides or removable bottoms to make this process easier. If you've used a baking pan, you may need to use a knife to help pry the soap loaf out. Cut the loaf into bars with a sharp knife. 

Naturally, you don't want your soaps to crumble when you cut them — and soapmakers have all sorts of ideas on which tools to use to cut soap with. Some use guitar strings, others use butcher's knives. Still others opt for specialty tools like this (and this). Some DIY-ers even fashion their own instruments. I use a ruler and score the top of the loaf with a sharp knife before cutting to make sure everything stays straight and even. I like generous bars, so I cut them about an inch thick.

Your work is now done, but the bars need to cure for 4 to 6 weeks (remember what I said about patience?) before being used. This time allows the water in the bars to fully evaporate, resulting in a harder and milder soap. Leave the soap to cure on a paper bag or baking rack in the same airy location. If you use a paper bag, turn the bars once or twice during the curing time to make sure all sides are equally exposed to air.

Cleaning up:

The pitcher, measuring cup, and spatula just need to be thoroughly rinsed with water. For the pot with raw soap residue in it, I usually wipe it out first with paper towels before washing it with dish soap and water. Use any tools that touched the lye only for soapmaking, and store them away from the kitchen, ideally on a shelf separate from other kitchen tools in common use, to prevent any chance of confusion.

Creating your own recipes:

This recipe is only one of practically endless combinations and ratios of fats, lye, and other ingredients that you can use to make soap. A lot of the fun of soapmaking is in exploring new recipes and seeing what turns out. Some of my favorite combinations have been orange and sandalwood with poppy seeds, lavender and clary sage with dried lavender blossoms, and rosemary and cedar wood with dried thyme.

You can also change the ratios and types of fat to make soaps with different properties, as well as using liquids other than water (such as milk). Online oil charts and lye calculators can help you finish your recipe. The proportions for this particular recipe are taken from Susan Miller Cavitch's The Soapmaker's Companion, a good all-around resource for learning about the science of soapmaking, exploring options for ingredients and techniques, and troubleshooting problems.

Congratulations, you're a soapmaker! Now get creative and have fun — but please be safe.

This post contains products independently chosen (and loved) by Food52 editors and writers. Food52 may earn an affiliate commission on qualifying purchases of the products we link to.

By Caitlin Pike

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