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How To Make Soap (The Cold Process)

This method of soap making involves making soap completely from scratch using the traditional method that our grandparents used. It is the most technical and takes the longest, but can create some of the best soap at an affordable price.

The cold process of soap making involves mixing a combination of fats (natural oils) with a lye solution until a process of saponification takes place. Saponification is a chemical process which converts a fat into a soap by reaction with an alkali (lye). Each fat has a saponification value which measures the amount of lye necessary to saponify one gram of fat. The amounts of the fats, along with their saponification values, are inserted into a mathematical formula that will give the total amount of lye needed to saponify a batch of soap. Just about any fat or combination of fats can be used. The qualities of the soap, such as hardness or softness, amount of lather, and whether it is harsh or mild, are determined by the types of fats used. Once the saponification process has begun to take place, at trace (the point at which a line begins to form when stirring the mixture) the soap is poured into molds and allowed to solidify. Once the soap has solidified (after a couple of days), the soap is sliced into individual bars and set aside to cure. The curing process generally takes up to 6 weeks.

Below is our step by step method for making soap using the cold process method. Each step will guide you through with detailed soap making instructions to help you complete your project.

Soap Making Supplies Needed:

Oils (fats)

Caustic Soda (lye)

Distilled Water

Newspaper

Safety Glasses or Goggles

Rubber or Plastic Gloves

Scale

Glass Jar

1 Lye Pitcher (plastic), it's best to mark this pitcher because you'll only want to use it for lye water

Long-handled Wooden Spoon

2 Thermometers (one for oils and one for lye water)

Stainless Steel Soap Pot (do not use aluminum pot)

Mold, Plastic or Wooden Container

Insulating Materials (blankets work well)

Freezer or Butcher Paper

Fragrance or Essential Oils

Colorant

Step 1
Select a soap making recipe and read through all steps carefully before starting. Assemble all ingredients and equipment making sure that all equipment meets the above requirements. Use of the wrong equipment can cause soap to not saponify properly.

Step 2
Cover a large, flat surface and surrounding floor area with several layers of newspaper.

Step 3
If using a wooden soap mold, line the mold with butcher paper making sure there are as few wrinkles as possible to prevent creases from forming on the soap. If using a plastic soap mold, spray with vegetable oil.

Step 4
Put on safety equipment (goggles and rubber gloves).

Step 5
Weigh out the required amount of lye into the glass jar. Do this by placing the empty glass jar on the scale and adjust the scale back to zero to prevent weighing the jar then add the required amount of lye. Set the glass jar full of lye aside.

Step 6
Weigh out the required amount of water into the plastic pitcher the same way the lye was measured.

Step 7
Carefully, pour the lye from the glass jar into the pitcher of distilled water. Never pour water into lye as this can cause the solution to splash up and out of the pitcher. If the solution does come into contact with the skin, rinse the area with vinegar and then running water. If the lye splashes into the eyes, immediately follow the manufacturer's directions on the lye container. Lye is a caustic soda and can be fatal if swallowed. Always keep lye out of the reach of children and pets. When working with lye make sure to wear protective eye wear and clothing. Be careful not to breathe in any lye crystals as they can cause serious burns.

Step 8
Using a wooden spoon, gently stir the lye solution until all the lye is dissolved. If lye crystals are not dissolved completely, chunks of lye can be left in the finished soap.

Step 9
The lye solution will immediately begin to heat up and the pitcher will become very hot. It will take the solution several hours to cool. Insert a thermometer into the solution, so that you can watch the temperature lower. It will need to cooled to a temperature of 100 degrees F.

Step 10
At the same time you are getting the lye solution cooled to 100 degrees F, the fats will need to be prepared. Place all measured fats (measured the same way as the lye) into a stainless steel melting pot and heat over low until the fats are melted. Insert the other thermometer into the melted fats and heat until they are 100 degrees F. If they are heated above this temperature, they will need to be cooled down.

Step 11
Remove your stainless steel pot from the burner and slowly pour the lye solution into the fats, stirring constantly with a wooden spoon. Make sure that you are still wearing your protective eye wear and gloves.

Step 12
Continue stirring the mixture until it begins to "trace". This process can take anywhere from 20 minutes up to 90 minutes. Trace means that the mixture is thick enough that when drizzled from the wooden spoon onto the surface, that it will leave a visible trail before it disappears.

Step 13
Add scents and colorants to the mixture (do not add before it starts to trace). Using the wooden spoon, gently stir to evenly distribute the fragrance and color. The use of a stick blender works well for mixing colorants, however, it will speed up the amount of time it takes for the mixture to trace.

Step 14
Immediately pour the mixture into the prepared mold and place a blanket over the top. This will keep the soap at a more even temperature as it hardens and begins to cure.

Step 15
Place the mold in a draft free area and allow to cool until solidified (a minimum of 24 hours and up to 48 hours).

Step 16
After the initial 24 to 48 hours, remove the blanket from the top of the mold. Test the soap with your fingers to see if it firm. If it isn't, allow it to sit in the covered mold for 24 more hours.

Step 17
Once firm, remove the soap from the mold and peel away the butcher paper.

Step 18
Place the soap onto a large cutting board and using a sharp kitchen knife, slice the soap into individual bars.

Step 19
Place the bars on a cooling rack and allow to cure for five to six weeks (the length of time for curing allows for all of the lye and fats to become completely saponified). After the soap has completely cured, it is ready to be used.

Congratulations, you have just created your own personal soaps using the cold process method of making soap. Now that you know what you are doing, you can experiment with different soap making recipes or make your own personal soaps from scratch by experimenting with different fragrances, additives and colorants.

Note: A thin powdery surface on the top of the soap is common and can be trimmed off. If there are hard, shiny spots appearing in the soap, this means that it has not properly saponified and the lye has been left in the soap. Do not use the soap if this is the case.

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