How to Make Homemade Soap

Follow these simple instructions for how to make homemade soap, and you’ll be making soap in no time.


"Soap" is the result of the chemical reaction called saponification that occurs when combining fat with lye.

Karen Keb

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Soapmaking is a homestead craft I had long wanted to try, despite my unfounded perception that it was difficult and dangerous. My ancestors made soap during the Depression using primitive methods – hardwood ashes and rainwater to make lye, fat rendered to make lard – and no one died, went blind or was burned (though a bar occasionally got stuffed into my mother’s mouth when something came out of it that shouldn’t have). The old-fashioned method of hand stirring – sometimes for hours – combined with the unpredictable strength of lye made from ashes resulted in soap that was highly variable and sometimes harsh on the skin of the person using it.

Modern methods and conveniences have taken just about all of these unpleasantries out of the equation. Though I’m usually a big fan of old-timey methods, I’m not quite so excited when chemical reactions are involved.

When I got serious about learning how to make homemade soap, I turned to a friend who’s been doing it for years and requested a hands-on demonstration. Sandra Johnson, a librarian in Baldwin City, Kansas, knows the craft inside and out. She happily agreed and sent me away with instructions to get the “only book I’d ever need,” Smart Soapmaking by Anne L. Watson – and read it cover to cover – and the supplies for one of her foolproof soaps.

When I showed up on the appointed lesson day at Sandra’s house, the schooling commenced. As a former schoolteacher, Sandra is exacting with her instructions, always stressing the importance of exact measurements, exact temperatures, and following instructions exactly.

This is precisely how you’d want a soapmaking teacher to be. By establishing the simple truth that if you follow procedure and use common sense, your soap will turn out, and no one will be harmed – just like home canning.

We began by gathering up all the needed supplies – food scale, glass bowls, measuring cups, pots, rubber spatula, stick blender, etc.

We staged the two necessary areas – the lye-mixing area and the main work area – and we prepared the mold for the soap using a free plastic bag from the grocery store. We then made Olive Palm Soap (see recipe on later in this article).

Thirty minutes later, we were finished with the process, and I had a perfect batch of soap setting up. My reaction, which is common, was “That’s it?” I couldn’t believe it! It wasn’t complicated and it wasn’t dangerous. Ingenious conveniences, like a stick blender, have made soapmaking easy as pie, so keep reading to understand for yourself.

The Story of soap

“Soap” is the result of the chemical reaction called saponification that occurs when combining fat with lye. The method detailed here is known as “cold process,” the most common technique for making soap by hand. (Cold process simply refers to the fact that with this method you don’t add heat once the ingredients are combined.)

Fats used for soapmaking can be animal (lard, tallow) or vegetable based (olive, palm, coconut); mineral oils cannot be used to make soap.

Lye is an alkali, the opposite of an acid, and a strong base. Today, the type of lye sold in hardware stores is the dry form of sodium hydroxide, or caustic soda, which is what we use for soapmaking. If your family has a tradition of making their own lye from leaching wood ashes, that’s a great history, but it’s not recommended anymore. Use the industrially produced kind with reliable and safe strength. 

Soapmaking equipment

Before embarking on soapmaking, gather or purchase (better yet, borrow to see if you enjoy it first) the following items:

Digital scale with a “tare” or “zero” button, that measures to tenths of an ounce or grams (or both)
Digital, waterproof, instant-read thermometer
Stick blender (immersion blender)
Soup pot with a minimum 8-inch diameter (stainless steel or enameled steel)
Stainless steel saucepan
Steel, stainless steel, or Pyrex glass roasting pan or deep dish that your saucepan fits into with room around all sides
Large glass measuring pitcher
Glass bowls or measuring cups
Two long-handled steel or plastic spoons, one slotted
Mold (quart- or liter-sized waxed cardboard milk carton, or rectangular glass Pyrex baking dish)
Plastic dishpan
Snug-fitting goggles  
Rubber gloves

Do not use any aluminum equipment – it reacts chemically with lye.

A note about gloves: Bulky rubber or PVC gloves can severely limit your dexterity – not a good thing when working with chemicals (or bees); some experienced soapmakers opt not to wear them. Use your common sense – find a pair that will allow you to press buttons on a scale and grab things with ease, while still protecting your hands and arms from accidental splatters.  

How to make homemade soap

Soapmaking is simple, but there are many details that you should know about before making your first batch. I urge you to get Smart Soapmaking and read it completely – it should take about an hour – to inspire and inform you further. 

Prepping the work areas

Allow yourself plenty of time – at least two hours to make soap the first time. Gathering the supplies and cleaning up will take the most time. Wear long sleeves, pants, socks and shoes; tie back long hair and keep all pets out of the work area. 

Set up in the kitchen or other well-ventilated area with running water and a sink (perfect if you’ve got a window above your kitchen sink).

For the main work area, assemble the following: scale, saucepan, soup pot, glass measuring pitcher or large glass bowl, glass bowl for measuring lye, glass bowl for measuring fats, small glass bowls for fragrance oil (if using), stick blender, long-handled spoon, rubber spatula, soap mold, paper towels, vinegar (for clean-up), plastic dishpan (in which to toss all used utensils), and all recipe ingredients.

Tip: Here’s an easy way to prepare the soap mold if you’re using a glass pan. Cut a plastic bag open and secure it in place using tape around the outside of the pan. Make sure to get as many wrinkles out as possible and get it nice and flat against the bottom and sides. 

For the lye-mixing area, assemble the following: roasting pan, instant-read thermometer, long-handled slotted spoon, pitcher of ice-cold water, bowl of ice cubes and paper towels.

Prepping the ingredients

  1. Place your saucepan on the scale and press the tare/zero button.
  2. Pour the distilled water into the saucepan until the correct weight is reached (measuring in grams is most accurate); if you pour too much, remove excess with a measuring spoon. Remove pan from scale.
  3. Place the soup pot on the scale, tare, and measure the liquid fat (oil). If your recipe calls for two or more oils, use separate bowls to weigh them, then combine in the soup pot.
  4. Place the large glass measuring pitcher on the scale, tare, weigh the solid fat.
  5. Heat the solid fat in the microwave until just melted, about 2 to 3 minutes – do not overheat.
  6. If you’re using fragrance oil, measure it into a small bowl and set aside.

Prepping the lye solution

  1. Put on your gloves and goggles.
  2. Make sure the glass bowl or cup that you’ll be measuring the lye into is completely dry, as well as everything else you’re using for the lye.  
  3. In your prepared lye-mixing area (preferably near the sink and window), place the bowl on the scale, tare, pour or spoon the lye into the bowl until the desired weight is reached. 
  4. Set the saucepan of distilled water into the empty roasting pan. Open the window or turn on your stove’s exhaust fan.
  5. Gradually pour the lye into the distilled water (never pour water into lye), stirring constantly with the slotted spoon. The solution will heat up and release fumes (hence the open window or fan) so try to stand back from it while still stirring, being careful not to splash. (Some people are very sensitive to lye fumes, so be careful and don’t let them collect.) The solution will be cloudy at first, giving way to clear as the lye dissolves. Make sure all the lye crystals are dissolved.
  6. Pour the cold water from the pitcher into the empty roasting pan (not into the lye solution) – as deeply as possible without allowing the saucepan of lye to float. Add the ice cubes to the cold water in the roasting pan. (This will cool down the lye solution.) Keep stirring the lye solution and lift up the saucepan a little to allow water to flow underneath it.
  7. Check the temperature of the lye, making sure the thermometer doesn’t touch the bottom of the pan. When the temperature cools to the range of 90°F to 110°F, take the saucepan out of the cold water and take it to the main work area.  

Combining Fats and Lye

  1. Take the melted fat out of the microwave and measure the temperature. If it’s not in the 90°F to 110°F range, reheat it for a few seconds. When it’s in the correct range, pour it into the soup pot containing the oil(s).  
  2. Slowly pour the lye solution into the soup pot with the fats. Stir with a long-handled spoon until well-combined (a few seconds or so).
  3. Check the temperature of the mixture and make note (it should be in the 90°F to 110°F range).
  4. Blend with the stick blender, keeping the tip completely immersed at all times. Move it around, tip the pan, making sure everything is thoroughly mixed. The mixture will quickly go from oily and transparent to creamy; it will thicken and become smoother, similar to thin pudding. Look for the oily ring – where the surface meets the wall of the pot – to disappear. Now you can stop blending. Stir the mixture with the turned-off blender to feel the thickness. Check the temperature; it should be a few degrees higher than when you checked last time since saponification generates heat. This is known as the “point of no return.” This whole step will take anywhere from 2 to 5 minutes, depending on the horsepower of your stick blender (up to 10 minutes with a very weak motor and a difficult recipe).
  5. If you’re adding fragrance oil, dump it in now and blend again for a few seconds to evenly distribute.
  6. Pour the mixture into the prepared mold, scraping the pot with a rubber spatula to get out as much as possible. Cover the soap with plastic wrap and set it on the kitchen counter or out of the way somewhere. Note that the soap will continue to generate heat as it saponifies, so if you touch it and it feels warmer yet, that’s normal.

Clean up

  1. Keep your gloves and goggles on while cleaning up. Put all of the used equipment into the plastic dishpan and wash by hand. If you’re using a dishwasher, place them inside; if not, wash a second time.
  2. Wipe down your work area with vinegar-dampened paper towels.
  3. Wash your gloves while they’re still on your hands.

Soap turn out

  1. After your soap has set for 24 hours, it should be ready to turn out. The soap should have cooled to room temperature and feel solid. The texture should be smooth with the consistency of cheese. If you’re unsure, you can opt to test the soap with pH strips (see Smart Soapmaking for details).
  2. Lift the plastic bag out of the pan and turn the soap block onto a cutting board. Using a sharp knife, slice the block into bars. If you like a neat-looking bar of soap or you’re giving it away as gifts, trim the edges, bevel them with a vegetable peeler, or use a special wavy soap cutter to create a decorative edge.
  3. Place the cut bars on a rack and set in a well-ventilated spot to cure and grow milder over time, at least two weeks, before using. The soap will become harder the longer it ages (you’ll avoid that gooey bar at the sink), so allow it to dry out thoroughly.
  4. Wash the cutting board. And that’s it – you have homemade soap!

Olive Palm Soap

From Anne L. Watson’s book Smart Soapmaking (Shepard Publications, 2007). 

This is a slightly harder soap with good lather and moisturizing properties.

18 ounces (510 grams) olive oil
12 ounces (340 grams) palm kernel oil
9 ounces (255 grams) distilled water
4.1 ounces (116 grams) lye
0.6 ounces (17 grams) fragrance oil, optional

Soapmaking ingredients notes

Olive oil: Use the inexpensive kind from the grocery store, not extra-virgin. It happens that the worst choice for cooking – olive-pomace oil – is best for soapmaking.

Palm kernel oil: A solid fat. Use good-quality, like that sold by soapmaking suppliers (see Sources).

Lye: The label should say “100% lye” or “100% sodium hydroxide.” Do not buy a drain cleaner that lists multiple ingredients – these cannot be used to make soap. In some communities, lye may be hard to find on store shelves because of the unfortunate fact that it’s also used to make illegal drugs. If you cannot find it locally, buy it from a soapmaking website.

Fragrance oil: Fragrance oils are different from essential oils. Essential oils are natural, but some people are allergic to them and many intricacies are involved in using them. Fragrance oil is an artificial aroma in a carrier oil, and the product is supposed to be nontoxic, even though some people are still allergic to them. Search for “fragrance oils for soapmaking”; further, make sure it’s suitable for cold-process soap, which should be stated by the seller.  

Karen Keb operates Prairie Turnip Farm in Osage County, Kansas, with her husband. Visit her blogs at and Common Fare at 

All soap is lye soap

Yes, you read that correctly. Some people believe that soap “made with lye” is harsh on the skin. However, all soap is made with lye, even glycerin soap and luxury soaps that fetch upwards of $8 a bar in boutiques. Lye is necessary for the chemical reaction that creates soap, called saponification, to occur. In soap that has been made properly, no lye remains in the final product.

Soapmaking sources

Mountain Rose Herbs
Supplies for soapmaking and an array of natural crafts.

Foods Supplies and equipment for soapmaking, beekeeping, candlemaking and more.

Hoegger Supply
Supplies and equipment for soapmaking, cheesemaking, dairying and more.

Smart Soapmaking book