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For many people, soap is a regular part of their personal hygiene routine. It’s useful for removing sweat and dirt from the skin.
There are plenty of options to buy in stores, but it’s also possible to make soap at home. Making a mild soap is fun and cost-effective. You can also choose the ingredients and scents based on your preferences.
To learn how to make homemade soap, read on for a recipe and tips.
Soap, by definition, is fat or oil mixed with an alkali. The oil is from an animal or plant, while the alkali is a chemical called lye. In bar soapmaking, the lye is sodium hydroxide. Liquid soap requires potassium hydroxide.
When oil and lye are combined and heated, the result is soap. This chemical reaction is called saponification. Without lye, saponification isn’t possible, so lye is necessary to create soap.
A note on lye
Some people are concerned about lye. On its own, it’s a highly corrosive substance that can irritate the skin, eyes, and respiratory system. However, when done properly, saponification turns lye into soap. No lye is left in the final product.
The following are basic soapmaking supplies, many of which you can find online:
- slow cooker
- plastic, glass, or stainless steel container (for measuring lye)
- heavy duty plastic, glass, or stainless steel container (for mixing lye and water)
- digital kitchen scale
- silicone spatulas (only used for soapmaking)
- immersion blender (with stainless steel shaft)
- candy thermometer (only used for soapmaking)
- silicone loaf mold (or individual molds)
- soap cutter
Avoid using aluminum or tin containers to handle lye, which can be unsafe.
Soapmaker safety equipment
You’ll also need safety equipment:
- safety goggles
- rubber or latex gloves
- oven mitt
- long-sleeved shirt
- well-ventilated work area
There are two methods for making bar soap from scratch:
- Hot process. In hot process soapmaking, external heat accelerates saponification. Most soaps can be used the next day, though it’s ideal to wait 1 week if you want a harder bar.
- Cold process. Cold process uses the internal heat that’s naturally produced during saponification. The bars will completely harden in 4 to 6 weeks.
The instructions below are for hot process soap. This method is beginner-friendly and has a fast turnaround. It yields 30 ounces, or 7 to 10 bars, of custom bar soap.
Later in the article, we look at different options and offer tips for choosing your own bar soap ingredients.
To make this DIY soap with coconut and olive oils, you’ll need:
- 20 oz. coconut oil
- 10 oz. olive oil
- 9 oz. distilled water
- 4.78 oz. 100 percent pure lye
- essential oils
- colorants (optional)
- dried herbs or flowers (optional)
Calculating fat to lye ratios
While you can adjust the ingredients to make smaller or larger batches, it’s important to calculate a safe amount of lye. This depends on the type and amount of oil. Always calculate the amount using the Handcrafted Soap and Cosmetic Guild’s lye calculator.
- Measure your ingredients and put on your safety gear. Set the slow cooker to low. Add the coconut oil.
- As the coconut oil melts, prepare the lye solution. Slowly add the lye to the water. (Do not add water to lye — this is unsafe.)
- With a spatula, carefully stir the solution as you add the lye. It’ll become hot and release fumes, which is normal.
- Set aside the lye solution, and let cool for 15 to 20 minutes.
- Check the oils. If the coconut oil has completely melted, add the olive oil. Stir well.
- Once the oils have reached 120 to 130°F (49 to 54°C), place the immersion blender on the side of the slow cooker. Gently pour the lye to avoid splashing. Stir slowly.
- Set the blender to low. Stir the mixture, moving in circles. Keep the blender immersed to avoid air bubbles.
- Continue blending and stirring for 10 to 15 minutes, or until the soap has reached trace. This is when the oils and lye solution have emulsified and look like pudding.
- Cover the slow cooker, and cook on low for 50 minutes. If the mixture bubbles, stir it gently.
- Turn off the slow cooker. Let cool until the mixture drops below 180°F (82°C). Add essential oils and colorants, if using. Mix well.
- Pour the mixture into the soap mold. Smooth the top with a spatula. Tap the mold onto your work surface to eliminate air bubbles. Top with dried herbs, if using.
Never mix water into lye, which can cause a dangerous chemical reaction.
A standard bar of soap is 3.5 to 4 ounces. The above recipe creates approximately 30 ounces. Depending on how you cut the soap, you’ll get 7 to 10 bars.
Soap finishing steps
Generally, here’s what the final steps involve:
- After pouring the soap into the mold, let it sit for 24 hours.
- Once cool, carefully remove the soap from the mold.
- Cut into bars with a soap cutter or knife. If you used single soap molds, simply pop them out.
- While the soap can be used at this point, it’s best to let it dry for another week. This will improve its hardness and quality.
Hot process soap has a rustic look, giving it a homemade appearance. But if you prefer more refined bars, consider trying the cold process method.
Also, compared to traditional, store-bought soap, DIY soap has a lighter scent. You can use more essential oil for a stronger smell, but this can be costly. Most people prefer the fainter scent of homemade soap.
For an enjoyable and safe soapmaking experience, follow the tips below.
Tips for soapmaking
- Always work in a ventilated area when preparing the lye.
- When adding lye to water, avoid touching the container with bare hands or breathing in the fumes.
- Never add the lye solution if the base oils are above 180°F (82°C).
- If using essential oils, you might need more or less drops depending on the quality.
- Fragrance oils are usually more concentrated. You may need less than 50 drops.
- Use one scent and one colorant until you understand how they affect the finished soap.
- You can use individual soap molds, which don’t require cutting.
The basic ingredients of soap are:
- animal fat or vegetable oil
- 100 percent pure lye
- distilled water
- essential or skin-safe fragrance oils (optional)
- colorants (optional)
Fats or oils
The best fat or oil depends on your preferences. Traditionally, soap was made with animal fat, but today, plant oils are widely used.
Depending on your oil, the finished soap’s hardness and lather will vary. Examples of fats and oils used in soapmaking include:
- olive oil
- coconut oil
- avocado oil
- almond oil
- jojoba oil
- hemp oil
- cocoa butter
- mango butter
- shea butter
Only use oils from animal or vegetable sources. Soap can’t be made with petroleum-based oils.
Water is an essential ingredient. It’s used to make a lye solution, which is combined with oil. The water helps the oil and lye complete the saponification process. By the time the soap hardens, most of the water will have evaporated.
It’s recommended to use distilled water. Some soapmakers use other liquids, such as:
These options can be tricky to work with if you’re a beginner, so it’s best to use water on your first try.
Technically, soap doesn’t need a scent to clean the skin. But if you’d like to add a pleasant smell, you can use essential oils or fragrance oils.
Essential oils are mostly plant-based and can be combined to create custom aromas. Fragrance oils are synthetic. When selecting fragrance oils, look for skin-safe options.
Soapmaking is a wonderful way to enjoy natural, gentle soap. It takes time to master the process, so don’t be discouraged if your soap isn’t perfect. The more you experiment, the better your soap will be.
Always follow safety measures and work slowly. For one-on-one guidance, consider taking a soapmaking class.
If you don’t want to work with lye, use a melt-and-pour soap base, which you can find online. It’s already been saponified, so you can experiment with soapmaking until you’re ready to make it from scratch.
Recipe adapted from The Prairie Homestead