Castile soap is a biodegradable soap made from olive oil, water and caustic soda. Created in Aleppo and brought by Crusaders to Castile, the area in Spain where the soap became famous. For centuries people have used this gentle cleanser for everything from cleaning skin and hair to washing clothes and floors. After making Castile bar soap, you can use it as a solid or mix with water to make a liquid soap. See Step 1 onwards to learn how to make your own Castile soap.
Step
Part 1 of 4: Preparing the Equipment for Making Soap
Step 1. Prepare your equipment
Set up your workplace in the kitchen or near a water source, and put all equipment in place until it's ready for use. Bowls, measuring utensils and other utensils that you use only to make soap - don't use them when you make food, as residue from the soap will be left on the utensils. You'll need these supplies to make Castile soap:
- Large measuring cup
- Stainless steel pot
- Big bowl
- Spatula
- Blender or mixer
- Meat thermometer
- Kitchen scales
- Rubber gloves and safety glasses (for handling caustic soda)
- caustic soda crystals (Sold in plastic containers, and you can store the rest when you're not using it; you'll need 125g of caustic soda to make 10 medium bars of soap)
Step 2. Prepare the oil
Castile soap was originally made from 100 percent olive oil, but many soap makers use a mixture of oils to make soaps with a balanced combination of ingredients. Pure olive oil will not produce a fine lather, and results in a bar soap that has a slimy texture. Coconut oil is widely used to help produce a better lather, and palm oil makes for a solid bar of soap. The ratio of olive oil:coconut oil:palm oil that makes a good soap is 8:1:1. For the soap recipe in this article, measure the oils in the measurements below. You will use a total of 1 liter of oil:
- 800 ml olive oil
- 100 ml coconut oil
- 100 ml palm oil
Step 3. Consider using essential oils
If you want a scented soap, you will need 10 drops of your favorite essential oil, or a combination of more than one essential oil for a total of 10 drops. Increase the amount of essential oil if you want a stronger scent, or reduce it to 5 - 7 drops for a softer scent. The essential oils used in Castile soap include:
- Peppermint
- Orange, lemon or grapefruit
- Lavender
- Rose
- Vetiver
- Pine
- Sandalwood
- Bergamot
Step 4. Prepare your soap mold
The mold you use will determine the shape and size of your bar soap once it's finished. If you want a rectangular bar of soap, choose a rectangular soap mold like white bread; You'll be able to cut it into as thick a stick as you want. Place the wax paper in the mold so that the soap is easily removed from the mold.
- You can find molds at craft supply stores and soap-making supply stores, and you can search online for the huge variety.
- If you don't want to bother buying molds, you can make used shoe boxes to make soap molds. Use a strong shoebox, secure the corners with tape to seal the edges and wax paper.
- You can also make soap molds out of wood, or use existing wooden boxes to make soap molds. The mold should be the size of the finished soap you want.
Part 2 of 4: Mixing Soda and Oil
Step 1. Put on your safety equipment
Baking soda is a caustic chemical that can burn the skin and eyes and harden in the lungs when inhaled. If this is your first time working with caustic soda, you will need to be extra careful to make sure you can use it safely. Put on your rubber gloves and protective goggles before opening the caustic soda container. Open the window and turn on the fan to ensure good ventilation in the room.
- Have a bottle of vinegar near you. If you spill caustic soda on the table, vinegar will work to neutralize it.
- If you accidentally touch or inhale too much caustic soda, quickly call your country's Poison Control Center, which you can find with online research. The US National Poison Control Center's number is 1-800-222-1222.
Step 2. Make a caustic soda solution
When you mix caustic soda with water, it's very important to use the exact size. For this soap recipe you need 300 ml of water and 125 grams of caustic soda. Use a different container to weigh, use a kitchen scale to get the exact scale of the recipe. Slowly add the baking soda to the water. The mixture will start to heat up and smoke, then the smoke will go away as it cools. The solution will take a few minutes to cool. Use a meat thermometer to check the temperature. The baking soda is ready to use when the temperature reaches 37.8 degrees Celsius.
- Never put water in caustic soda - always put caustic soda in water. Adding water to caustic soda will create an explosive reaction.
- When you weigh ingredients, make sure the scale is zero when the container is placed on the scale so that the weight of the container is not included in the ingredients scale.
- If you are making more or less soap, use a caustic soda calculator to find out the exact amount of water and caustic soda to use.
Step 3. Heat the oil
While waiting for the caustic soda to cool, heat the oil. Put the oil in a saucepan and heat it over medium heat. Stir in oil. Continue to heat until the oil reaches 37.8 degrees Celsius. Use a meat thermometer to determine when the oil is ready to mix with the baking soda. The oil and caustic soda should be as close to temperature as possible to mix well.
Ignoring the supposedly close temperature of the oil and caustic soda will result in soap that doesn't harden properly. Be sure to use a thermometer to measure the temperature of both solutions and complete this important step
Step 4. Mix caustic soda with oil
Pour the caustic soda solution into the oil solution. Use a blender or mixer to start mixing. After a few minutes, the dough will start to thicken. When you can see the traces made by the blender, the mixture is well blended. The consistency should be like the thickness of honey.
You can use a spoon to mix the soda with the oil, but it will take a lot longer to mix the mixture thoroughly if you use a spoon
Step 5. Add essential oil
Once the mixture is well blended, you can add oil to give the soap a scent. Add 10 drops of essential oil and mix with the soap mixture until thoroughly combined.
Part 3 of 4: Pouring and Storing Soap Until It's Ready to Use
Step 1. Pour the soap into the prepared mold
Be careful not to spill it, pour it directly into the mould. Cover with a towel or dish towel, and make sure the cloth doesn't touch the soap, but instead hangs over the mold. This cap is to protect the soap from dust or insects. Leave it for 48 hours.
- During the first 48 hours, the soap will harden slightly. But the soap is not ready for use; must be processed first, so that the water evaporates and the soap becomes softer. Do not use soap immediately, because it will be hard on the skin.
- Check the soap surface after 48 hours. If there is a film-like layer on the surface, or it looks like it is separating, the soap cannot be used. That means it contains too much caustic soda, which can hurt your skin if used, or that the caustic soda and oil don't mix properly. Unfortunately there's nothing you can do when this happens - you'll have to throw away the soap and start all over again.
Step 2. Remove the mold from the soap
Store-bought molds have sides that you can easily remove to remove soap. If you're using a shoebox, you can either pry it out or cut off the side that's stuck to the mold. If you are using a special mold, you can just remove the soap.
Step 3. Cut the soap into a bar of soap
Decide how thick you want it to be. The standard size is 2.5 cm, but you can make it thicker or thinner. Use a ruler to measure the thickness of the soap, and draw a line along the length of the soap to mark the line to be cut. To cut it follow these options:
- Use a sharp knife. Don't use a serrated knife, unless you want to get a wavy side of the soap.
- Use cutters. This is a commonly used tool for cutting dough, and will be suitable for cutting soap.
- Cheese cutter. Make sure the wire is straight so the cut is straight and vertical.
Step 4. Put the soap on to preserve it
Line a thin baking sheet or tray lined with wax paper and place the soaps on top. Place in a cool, dry place for preservation for 2 weeks to 9 months. The longer you wait, the better the soap will work; produces a thick foam and has a better texture.
You can start using soap after a few weeks. When ready to use, the soap will be firm, without the slightest chemical smell
Part 4 of 4: Making Liquid Castile Soap
Step 1. Grate 110 g of solid Castile Soap
That number is the weight of one medium-sized bar of soap. Use a cheese grater or knife to grate it into small pieces. This will help the soap mix with the hot water more easily.
Step 2. Bring 8 cups of water to a boil
Pour water into the pot and turn on the stove over high heat. Bring the water to a boil.
Step 3. Mix water and soap granules
Pour the water into a pitcher or large plastic bowl, then stir in the soap globules. Let the dough sit for a few hours until it thickens slightly. If it's too thick, you may have to heat it up again and add more water. The consistency should be like that of shampoo at room temperature.
Step 4. Pour into the container
Put the liquid soap in a plastic bottle and store it in the bathroom or kitchen. Liquid soap will last for months at room temperature. Use it to wash your hair and skin, clothes, dishes or other items in your home.
Tips
- Try experimenting with additional oils like lavender, eucalyptus, or citrus essential oils to create a soapy scent and add color.
- Try changing the ratio of base ingredients to change the texture, strength and aroma of your soap. Better to start with less caustic soda than too much.
- A stick blender will make the process of adding the caustic soda solution to the oil solution easier and faster. It's important to mix the caustic soda solution with the oil until smooth, so mix vigorously.
Warning
- Castile soap does not produce a lot of lather but cleans just as effectively as soap that produces a lot of lather.
- Be careful handling the caustic soda and adding it to the water. Rubber gloves and a well-ventilated room are good ways to keep caustic soda from burning and giving off unhealthy fumes.
