Cold Process Soap Making Tutorial

Do you want to learn how to make soap completely from scratch?

Throughout this guide we are going to explain the entire cold soap making process from start to finish. By the end you will have learnt everything you need to know about creating your own unique and beautifully handcrafted soaps, completely from scratch.

Whether you are a complete soap making novice, or expert you'll definitely learn something new about how to make soap at home.

The first thing you must do is understand what soap is. This is absolutely vital in learning cold process soap making. Please see our What is Soap? article before continuing.

Now you are fully informed on what soap is, and how it is made, it’s time to gather your ingredients. You will need your chosen Soap Making Oils, Sodium Hydroxide, Essential Oils, Fragrances, Colourants, Soap Moulds, two large soap making pots, thermometer, scales and a large soap/pizza cutter.

The most enjoyable experience about cold process soap making is you choose from start to finish exactly what goes into your product, so the ingredients you chose are completely unique to you! Once you have your equipment ready, be sure to wear protective gloves and goggles throughout the entire process as you will be handling harmful chemicals which can lead to serious injury.

Step 1 - Preparing your lye solution:

Measure out with total accuracy your sodium hydroxide (Lye) according to your recipe or see Soap Supplier saponification table, with the exact amount of water. If your soap recipe doesn’t state how much water to use, the general rule is 3 parts water to 1 part lye. Make sure you do not use hard water in cold process soap making as the unwanted chemicals in the water could react and ruin your soap. If you have hard water, we recommend either purchasing a water softener or simply buy distilled water. Once you are ready with the exact amount of Lye and water, add the lye to the water in the soap making pot (not water to lye!) and begin mixing until the lye has fully dissolved. The reaction alone will reach temperatures up to 93°C so make sure your chosen pot can withstand those temperatures. Be warned, if you add too much water, the finished soap can become too soft, whereas too little water and the soap can become too caustic and dry. Your recipe will specify what temperature the lye should be to combine with the oil, so leave to cool and check the temperature regularly. The usual temperature is 35°C.

Step 2 – Preparing your oils:

Now add your carefully measured liquid oils to a separate soap making pot and stir. If you have chosen to use solid oils, melt them carefully using a microwave or hob and pour with the rest of the oils to slightly above there melt point (typically 35°C). Remember, it is crucial to use the correct measurements of lye and oil, too little oil and the soap will be too hard and caustic, too much and it will be too soft. Now insert your second thermometer into the oil mixture checking regularly until reaching the desired temperature.

Step 3 – Saponification:

Now wait for your lye and oil solution to reach the desired temperatures; you can speed up the process by placing the soap making pots in hot or cold water. Once both pots have met their desired temperatures, pour the oils and fats mixture slowly in the lye solution and stir vigorously in a figure eight to assure all the necessary molecules are interacting. You can test if the mixture by drizzling the mixture from the mixing spoon on the surface of the liquid, if it floats for a brief period and then sinks back into the solution saponification has taken place. This is called the ‘Trace’ stage. Keep stirring for anything from 45 minutes to an hour, though the ‘Trace’ stage can vary greatly from different oils used or if handheld blender has been used to the time is greatly reduced.

Step 4 – Personalise:

Once you are in the ‘trace’ stage, it is now time to add your essential oils, fragrances, colours and exfoliants. Stir thoroughly until the mixture is even throughout, and pour into your desired soap mould. Cover the mould with towels or any other insulating material to maintain as much heat as possible, this is essential for the curing process. Now leave the soap to cool for 18 – 36 hours, depending on the ingredients used.

Step 5 – Curing:

Once your soap has solidified, slice your bars into the desired thickness, or alternatively trim and carve the soap into your desired shapes. If you have used individual moulds, take out your finished bar, place the shaped soap onto a rack to allow air to circulate around it, turning them over once every 6 to 8 days. Depending on the recipe, the curing process can take anything from 3 to 8 weeks; this allows the pH level to drop to a mild and homemade soap bar. Once the curing period is over, scrape off any residual white powder (soda ash) on the surface of the bars, as the substance can be harmful to the skin. Congratulations! You have now successfully created your very own handmade soap bars from scratch. Don’t forget to add any decorative packaging or ribbons to finish off the truly hand made look! Happy Soap Making!