Mother Earth Living

Cold-Process Soap Making

Try cold-process soap making and create all-natural soap bars to pamper your family and friends.
By Deborah Niemann
February 2012

“Homegrown and Handmade” shows how making things from scratch and growing at least some of your own food can help you eliminate artificial ingredients from your diet, reduce your carbon footprint and create a more authentic life.
Photo courtesy New Society Publishers (c) 2011

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Avoid artificial chemicals and fragrances that irritate your skin by making your own soap. Follow these easy step-by-step instructions for cold-process soap making, and soon you’ll be using essential oils, natural clays and oatmeal to make truly unique and lovely soap bars. Suggestions about equipment, instructions and safety, as well as three soap making recipes can be found in this excerpt, taken from Homegrown and Handmade (New Society Publishers, 2011). This excerpt is taken from Chapter 13, “Producing from the Home Dairy.” 

We had been on our homestead for a few months when I complained to a friend about my allergy to commercial soap. I had found only one unscented soap at the health food store that did not make me itch or sneeze, which was painfully boring for a former fragrance junkie like me. I used to be one of those people who had six or seven perfumes with matching soaps and lotions. Gradually, they began making me sneeze or itch or both. My friend interrupted my complaining to suggest that I start making my own soap because, she said, “You have goats.” I had no idea how goats and soap were connected, but she said that I could use my goat milk to make soap.

Even though I saw soap recipes that called for very specific amounts of lye, such as 6.7 ounces, I was initially put off by the idea of buying a digital scale. People have been making soap for millennia, and they didn’t have digital scales; right? As I discovered with a lot of other things, the answer is not that simple. Soap is one of those things discovered by accident. At its simplest, soap is merely water, ashes from a fire, and melted fat from an animal. It is easy to imagine these being mixed by chance all over the world. Soap is mentioned in writings from many early civilizations. Although it appears soap made cleaning easier, we don’t know much about the quality of the soap made three or four thousand years ago. The quality probably varied tremendously from place to place because it was made from different oils in different places.

We do know that a couple of hundred years ago, it was not easy to make a good batch of soap. On American homesteads, lye was made from water that dripped through a box of ashes. If an egg floated in the liquid, the lye was thought to be strong enough. If the egg didn’t float, the liquid was poured through the ashes again. As you might imagine, this was not a very reliable method. Soap that did not contain enough lye was too soft, and soap that contained too much lye was too harsh. Making a good batch of soap was more art than science, and some women had a knack for it. Just as some were famous for their delicious bread, some were known for their excellent soap. So, although you can make soap without a digital scale, the quality will be questionable. The amount of modern lye that makes the difference between a gentle batch and a harsh batch can be as little as a quarter of an ounce in a small batch of soap, which is tough to eyeball with measuring cups. Although I initially resisted the digital scale, after I bought it, I used it daily for weighing goat milk, as well as when canning or freezing fruits and vegetables.

Soap Making Safety

Six months passed from when I started reading about making soap until I finally did it. Why? Because I didn’t want to wind up blind or with a hole burned in my arm. A lot of information written about soap making is nothing less than terrifying. Yes, lye is wicked stuff, but you need not be terrified if you understand how it works and take a few safety precautions.

Do not make soap when you are in a hurry or are distracted. If you have small children, make sure someone else is available to take care of their needs while you are making soap. There are times when you absolutely should not leave the area during the process. Every soap-making accident I’ve read about that involved a bystander happened when the soap maker’s back was turned or the soap maker left the room for a moment. In one story a woman’s husband walked in and drank the lye solution, which was in a pitcher. In another, a toddler reached up and grabbed the handle of a pitcher filled with the lye solution when his mom turned her back for just a moment. If you have never made soap before, schedule at least one hour when you know you will not be disturbed. If you have pets, especially a cat that might jump on the counter, lock them in another room.

Virtually everything written about personal safety with lye says to wear neoprene gloves, chemical resistant goggles, and long sleeves. Personally, I don’t wear gloves, because they are lumpy and awkward, and I worry that they will make me more likely to drop something. If lye gets on my hands, it is easy for me to immediately wash them under running water. I have had little splatters get on my hands, and after rinsing under running water, I also rinse with vinegar, which neutralizes any remaining lye. (Vinegar is an acid; lye is a base.)

I have really mixed feelings about the long sleeves, because if you spill the whole pot on your arms and you are wearing long sleeves, the now-drenched fabric will cling to your skin, possibly causing a worse chemical burn than if you were not wearing long sleeves. And you would need to pull off the lye-soaked shirt, possibly getting lye on other parts of your body. If you decide to have your arms covered, I recommend putting on a second layer — a jacket or sweater that buttons or zips up the front that you could easily take off without pulling it over your head.

Eye protection is an absolute necessity, and it is a lesson I learned the hard way. I knew eye protection was important, and I am usually wearing reading glasses when I am making soap. However, one afternoon I was making soap — in a hurry because I had an appointment in an hour — and I absent-mindedly pulled off my glasses just before I poured the soap mixture into the mold. It splattered and hit my left eyeball.

If you get lye or the unsaponified (lye and oil) soap mixture in your eye, you are supposed to flush your eye under running water for fifteen minutes and then go to the emergency room. I had always wondered why you need to go to the hospital after flushing your eye. Well, once the lye hits your eyeball, damage is done. Flushing the eye gets the lye out so that the damage is minimized. At the hospital, they were able to check the pH of the eye to make sure all of the lye had been rinsed out. Then they examined the eyeball for damage. Because I had chemical burns on my cornea, they sent me to an ophthalmologist for further treatment. Within a few days, my vision was completely restored.


You need the following equipment for soap making:

• digital scale to weigh ingredients
• stainless steel or enamel pot for melting oils and mixing soap (Do NOT use an aluminum pot because lye does not get along with aluminum, and it will get ugly.)
• 8-cup glass mixing bowl with handle or nonaluminum pitcher for mixing lye and liquid
• 2-cup glass measuring cup for weighing lye
• glass or cup for weighing fragrance or essential oils
• thermometer (needs to read 90 degrees – 140 degrees)
• plastic spatulas or wooden spoons for mixing
• stick blender for mixing (also known as an immersion blender)
• mold (professional soap molds, stainless steel muffin tins, plastic storage containers, cardboard juice or potato chip containers)
• freezer paper or wax paper (to line mold, if necessary)
• vinegar (to neutralize lye in case it splatters on skin)


Oils — You can make soap with any oil. Historically, soap was made with whatever was available locally. In North America, that meant lard from pigs or tallow from cattle. In the Mediterranean, that meant olive oil. Today we realize that various oils contribute certain properties to soap. Although you can still make your soap with 100 percent lard, it will not lather like modern soap, and most of us equate lather with clean. Coconut oil creates lather in your soap, but it is not very good for your skin. Olive oil makes soap that is very gentle, but it has no lather. This is why modern soap recipes include multiple oils.

Palm oil separates as it cools, so you need either to buy homogenized palm oil or to melt all of your palm oil, mix it up, and then weigh it. It is not hard to find stories of failed soap batches online from people who were not aware of this. If you simply scoop out the oil, your initial batches of soap from the top of the container will turn out, but batches made with the oil at the bottom of the container will not saponify correctly. If you buy homogenized palm oil, it must be protected from melting in storage, because it will separate. 

Frozen milk — You can use any type of milk for making soap, from skim to whole milk, and it can be from cows, goats, or sheep. For best results, you should freeze your milk before using it in soap recipes. There is no need to pasteurize it. After milking, strain it into a container that is safe for freezing. It should be frozen in the amount you will be using in your soap recipe. To use the milk, remove it from the freezer with enough time for it to start to thaw. It should be thawed enough to break it into several smaller pieces. When you sprinkle the lye onto the frozen milk and stir gently, the lye-milk mixture will start to heat up and melt the frozen milk within a few minutes. If you use refrigerated milk, it will turn bright orange and the milk will separate. It won’t be pretty, and it may or may not turn into soap.

• Lye — Because lye can be used to make crystal methamphetamines, it is getting harder and harder to find it locally. Some hardware stores still carry it, but if the label says it is a drain cleaner, read the ingredients to make sure it is 100 percent pure lye, because most drain cleaners have added chemicals that would not be good for soap.

Essential oils — If you have allergies, you should use essential oils to scent your soaps. Start with a single essential oil so you will know the guilty party if you have a reaction. After you know which essential oils work for you, you can start blending and mixing. Purchase your essential oils from a soap making supply company because you will need two to four ounces in each batch and if you buy little half-ounce bottles from a health food store, it will cost a fortune to make a batch of soap.

Fragrance oils — Stay away from fragrance oils if you want to make all natural soap. These oils are a blend of natural and artificial fragrances —sometimes hundreds of them — making it impossible to figure out the cause if you have an allergic reaction to the soap. Most fragrance oils are proprietary blends, meaning the manufacturer does not have to reveal the ingredients because they are trade secrets. People like them, however, because they are much cheaper than some essential oils, such as sandalwood.

Herbs and botanicals — You can add herbs to your soap, but most of them will not do much to scent or color the soap. Because of the heat created during saponification, most herbs will turn brown or black. Rose hip powder will add a bit of speckled color and gentle exfoliation, although it won’t add fragrance. Oats ground in a coffee grinder can be added to soap. Wheat germ will add light brown speckles to soap and provide gentle exfoliation.

Clay — Natural clays can be added as colorants. Some are skinconditioning agents for dry skin, while others absorb oil in oily skin. A small amount of clay will create more “slip” in shaving bars so that the razor glides across the skin. Too much clay, however, can clog twin-blade razors. Clays are available from soap making supply companies.

Pumice or egg shells — Either pumice or egg shells can be added to soap to create a scrub bar. Pumice is available from soap making supply companies. Egg shells, washed and dried, can be ground in a coffee grinder and added to make a scrubby soap for hands.

Cold-Process Soap Making

The old-fashioned way of making soap involved stirring and cooking the lye and oil mixture for hours over a fire. This is referred to as hot-process soap making, and some people still use this method today. Many, however, prefer cold-process soap making because it requires a lot less time on the part of the soap maker. You mix up everything, and the chemical reaction of the lye heats up the mixture and magically makes soap.

Before starting to make soap, make sure you have all of the ingredients on the counter and ready to be used. Do you have a bottle of vinegar available in case a little lye splatters on your skin? Are your molds ready to receive? If you have purchased professional molds, such as little animals or flowers, they may need to be sprayed with oil to make it easier to unmold the soap. If you are using a wooden box or loaf mold, you should line it with freezer paper or the soap will stick to it and be a challenge to remove.

1. If the recipe includes any oils that are solid at room temperature (like palm oil or cocoa butter), weigh them and put them in a stainless steel pot on the stove. Heat just until melted and turn off burner. Weigh liquid oils and add them to the melted oils and stir. The temperature should be between 100 degrees and 120 degrees, unless you heated the solid oils more than necessary. If it is above 120 degrees, wait until the temperature is down to 120 degrees before moving on to the next step.

2. Put frozen goat milk chunks into the 8-cup mixing bowl or pitcher.

Weigh lye and slowly add it to the frozen goat milk chunks, and stir gently until lye is completely dissolved. The lye will melt the frozen milk within two or three minutes. You must ALWAYS add lye to the liquid. Never pour any liquid into lye because it could cause a violent eruption resulting in injury. The temperature should be between 100 degrees and 120 degrees when the milk is melted and all of the lye is dissolved. The more frozen the milk is when you add the lye, the closer you will be to this temperature range. If the temperature goes above 120 degrees, wait until the temperature is down to 120 degrees before moving on to the next step.

3. Gently pour the lye mixture into the oil mixture.

Using the stick blender, mix the lye solution and oil. If you are adding anything else — oatmeal, herbs, essential oils — do it now. The warmer the temperature of your oils, the faster the mixture will reach trace, which is when you will pour it into the mold. If you are new to soap making, you may want to work with oil temperatures closer to 100 degrees. Some fragrance oils will accelerate trace, which is a good reason to start with either unscented or a single essential oil for your beginner batches. The mixture has reached trace when it is the consistency of a thin pudding. When you lift the stick blender from the mixture, drops and dribbles will sit on the surface rather than disappear into liquid. Now is the time to pour into the mold.

If the mixture gets to the consistency of mashed potatoes, it has seized and will be too thick to pour. You will need to spoon it up and mash it into a mold. It won’t be pretty, but it will turn into soap, and you can still use it.

4. After pouring the soap into the mold, you can cover it with a piece of wax paper or freezer paper to keep ash from forming. This is exactly what it sounds like — a white powder that forms on the top of the soap as it dries. Ash is harmless, but some people don’t like the way it looks, and it can easily be avoided if the surface is not exposed to air during the first 24 hours as it saponifies.

5. Most soap making directions use water to dissolve the lye and will tell you to insulate your molds with a blanket or multiple layers of towels at this point. Do NOT do this when making soap with milk. Milk causes the soap to heat up more than a lye-water mixture. If the soap overheats in the mold, it will rise like bread, and there will be a tunnel through the center of the loaf. It’s not pretty, but it is not harmful either.

6. Let the soap sit for 24 hours in a safe place where children and pets can’t grab it or knock it over. After 24 hours, it can be unmolded and sliced. Depending upon the recipe, you might be able to slice the soap a month later, but many recipes require the soap to be sliced as soon as possible. I once made the Gardener’s Scrub Bar at a conference, then brought it home and forgot about it for six weeks. At that point, it was like trying to slice a six-pound hunk of chocolate. Each time we tried to slice it, it would crumble and break off in chunks.

7. Place bars on a wire rack or shelf to air dry for three or four weeks before using.

Soap making recipes are NOT like cooking recipes, where you can substitute one type of oil for another. Saponification values are different for different oils. You should always use the oil indicated in the recipe! 

All of the following recipes will fill two regular size cardboard potato chip cans. If you use them as molds, they do not have to be lined or sprayed. After twenty-four hours, peel away the sides of the can from the soap, starting at the top edge.

These recipes can be doubled if you want a larger batch. However, I recommend you only make this amount for your first attempt at soap making. This quantity is easier to work with, and if the batch doesn’t turn out well, you haven’t wasted much oil or milk.

Castile Soap

Castile soap is one that is made mostly or entirely of olive oil. This recipe contains 54 percent olive oil. It is the first recipe I created, and to this day, it is still one of my favorites for showering, washing hands, and washing my face. Makes twelve 5-ounce bars of soap. 

• 24 ounces olive oil
• 8 ounces palm oil
• 8 ounces coconut oil
• 4 ounces sweet almond oil
• 13 ounces milk
• 6 ounces lye
• 2 ounces essential oil (if desired — lavender, orange, or grapefruit work well)

Gardener’s Scrub Bar 

This is the soap that sits at the kitchen and bathroom sinks at our house. If you need a soap that really cleans your hands, this does the job. I use tea tree oil because it is reputed to kill germs. Although this is far gentler than commercial soaps, it is not as conditioning as the castile soap if you have dry skin. And remember, you need to slice this soap when it is 24 to 48 hours old. It gets hard fast! Makes twelve 5-ounce bars of soap. 

• 16 ounces coconut oil (1 pound)
• 16 ounces olive oil (1 pound)
• 12 ounces palm kernel oil
• 6.7 ounces lye
• 13 ounces milk
• 2 tablespoons pumice or ground eggshells
• 1 ounce tea tree oil

Facial Soap

After seven years of using my castile soap on my face, I decided I wanted to try something a little more special. I came up with this recipe, which my teenage daughter also loves. French pink clay is very gentle, and it is good for all skin types. It is reputed to be good for acne, and my daughter agrees. The essential oils are optional, but they blend together for a heavenly scent. Makes twelve 5-ounce bars of soap. 

• 4 ounces avocado oil
• 2 ounces castor oil
• 4 ounces cocoa butter
• 2 ounces grapeseed oil
• 16 ounces olive oil (1 pound)
• 4 ounces palm kernel oil
• 4 ounces palm oil
• 8 ounces sunflower oil
• 5.8 ounces lye
• 13 ounces milk
• 3 ounces French pink clay
• 1/2 ounce grapefruit essential oil
• 1/2 ounce bergamot essential oil
• 1 ounce ylang-ylang essential oil

Making Your Own Soap Recipes

What if you can’t find palm oil in your area, or what if you are allergic to coconut oil? You can alter the above recipes or make up your own recipes from scratch if you use a lye calculator to determine the proper amount of lye for the oils you are using. You enter the weight of the oils you are using, and the calculator recommends the amount of lye needed. Lye calculators are available to use on several soap making supply websites. There are also tables online that require you do some math to figure out exactly how much lye can be saponified by certain oils. Most soap makers shoot for around 5 percent excess fat in recipes so that the soap is gentle on the skin but the bar is not too soft.

This excerpt has been reprinted with permssion from Homegrown and Handmade, published by New Society Publishers, 2011. 

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