A Complete Course of making Natural solid Soaps with Cold Process Technique
Table of Contents
2. cold process
What is soap?
Soap is the result of a chemical reaction (saponification) between a fatty body (often a mixture of vegetable oils) and a basic solution (lye + water), this mixture is called soap paste.
The fatty acids of the oils are transformed into surfactant molecules (which are mainly cleansing, foaming and softening).
What manufacturing processes?
• Hot saponification process: used by manufacturers for all types of soap including Marseille or Aleppo soap.
Saponification is complete and fast. Soap paste is cooked in a large pot in the presence of excess soda. The soap paste is then washed several times with salt water inevitably extracted during these operations.
The unsaponifiable part of the oils (rich in antioxidant molecules and vitamins) is destroyed by heat during cooking. The hot soap therefore contains neither glycerine nor unsatisfactory, this very hard soap creates an imbalance of the hydrolipidic film (having the role of protecting the skin by forming a protective barrier to bacteria, fungi and avoid drying out).
The main advantages of the industrial method lie in the fact that soaps are immediately usable and that the resale of glycerine to the cosmetic industries increases financial gains.
• Cold saponification process: a method used by artisanal soap makers.
Cold saponification process consists of mixing oils and lye without energy input. The saponification reaction stops when all the lye molecules are used.
To ensure a good dosage of lye, the soap maker calculates an amount of oil in excess (usually 5 to 8 %), the soap is therefore over-fat.
This artisanal process requires a drying time of several weeks for the reaction to be completed and it is possible to use soap.
No elements are removed or added to the soap paste, the natural glycerine obtained by chemical reaction and the unsaponifiable part of the oils (unheated) are in the finished product.
The cold soap has therefore preserved:
- Over-fat: 5 to 8% unprocessed bringing softness to the skin, we find directly the properties of oils in the soap).
- Natural glycerine: creates during saponification providing hydration and protection to the skin.
- Insaponifiables: softeners, anti-inflammatory, protective, antioxidants, etc.
Cold process soap respects and strengthens the hydrolipidic film, it can be related to natural care.
Making natural solid soap with cold process:
Soap is the product of a chemical reaction between a fat (vegetable oil, vegetable butter, animal fat, etc.) and a strong base (lye or potash).
For the manufacture of solid soap, soda (lye) (sodium hydroxide) is used.
Potash (potassium hydroxide) is used to produce pasty or liquid soaps (black soap, liquid Marseille soap).
We will talk here only about the manufacture of solid soap, soda.
The oils and butters consist mainly of triglycerides of fatty acids. When lye is added, it is transformed into soap according to the following reaction (R represents the carbon chain of fatty acid, a long chain of 12 to 22 carbon atoms for the most common fatty acids in vegetable oils):
Make your first natural solid soap with cold process:
We will explain step by step of how to make your first bar of soap
• A scale.
• A Pyrex, glass, or heat-resistant plastic bowl.
• A Pyrex or heat-resistant plastic beaker.
• A plunge foot, plastic, silicone or stainless steel mixer to mix the soda if you
use solid soda.
• A large silicone or plastic spatula to help you pour the soap into the moulds.
• Optional: a resistant thermometer (glass or stainless steel), especially useful if
you use pure soda (in its solid form) to control the temperature of your soda
solution before mixing it with oils.
• Laboratory equipment (mask, gloves, gown, glasses).
Handle all ingredients with care and refer to image for more details.
A cold process soap consists of 3 essential ingredients:
1. Vegetable oils or butters.
2. Demineralized water.
3. Caustic soda (sodium hydroxide).
Read below for detailed information.
1. Vegetable oils and butters:
Learning about oils and knowing them is necessary. Although they have the name of oil or butter, they all have different properties and especially a special role in saponification.
Let’s talk about oils with cleansing and foaming power: these are those that contain saturated fatty acids like copra oil, coconut oil, palm oil, cocoa butter, Shea, bay berries, ideally, they must make up 20 to 30% of the oil mixture.
For the rest of the soap, liquid vegetable oils rich in unsaturated fatty acids: apricot oil, sweet almond, hazelnut, argan; avocado, grape seeds, sesame, etc. Be careful, some of these oils tend to rancid, which will damage the properties and appearance of our soap.
We learn and use them up to 15% of the total oils.
Special note for olive oil. Like the oils mentioned above, it contains unsaturated fatty acids, but what makes it different is that it makes solid soaps. It can therefore be used in large part in the making of soaps up to 100%.
We like it for its softness and ease of use. Personally, I like to use it up to 40 or 60% in my oily preparations.
Castor oil is also an oil in its own right, it provides a very creamy, stable and pleasant foam as well as a great soap sweetness. Only 5% maximum is used to avoid soap that is too soft.
You can use the following table to better formulate your recipe:
2. Lye or Sodium hydroxide NaOH:
This is the agent that allows the transformation of oils into soap.
Be careful not to confuse caustic soda (sodium hydroxide) with soda crystals (sodium carbonate) or baking soda, which cannot be used in saponification.
Soda (lye) is an extremely caustic product (very corrosive, causes serious burns) that should be handled with the greatest care.
The amount of lye needed must be accurately calculated:
The quantity of each oil is multiplied to the sodium saponification index of this oil.
It is necessary to know the saponification index. Please refer to then following table:
Note that at the end of saponification, after the treatment period, all the lye will have reacted with the oils to give the soap. The finished soap no longer contains lye.
1. Demineralized water H2O:
To dissolve the NaOH soda (lye), it is important to pour the lye into the water and not the other way around.
Amount of water needed is calculated according to the lye value: the value of NaOH is multiplied to 2.5 = quantity of water. Qty water = Qty NaOH * 2
2. Other optional ingredients:
Mineral dye: (ochres, clays, oxides, micas) are insoluble and are simply added at the time of trace, possibly pre dispersed in a little vegetable oil. The colors are usually very stable.
Clays: bring interesting properties.
Ochres: give beautiful shades of natural land.
Oxides: have a very intense dye supply (be careful not to overdose them).
Micas: bring a touch of satin gloss (use them in small doses).
Plant dyes containing water-soluble organic pigments (chlorophyll, seaweed, nettle, coffee, caramel…): they are added
to the soda water, in dilution or maceration, or added at the end (whole plants in powder or finely ground: nettle, parsley…).
Plant dyes insoluble and which color by dispersion (cocoa powder, cinnamon, Charcoal vegetable. Depending on the fineness of the powder, we will often have visible grains and light exfoliating effect.
The percentage of using is 2 to 5%.
It is quite possible to add perfumes and essential oils to the soap. Some essential perfumes or oil are heat sensitive and may lose their properties.
The only essential oils that were problematic are citrus oils. Limit them to small amounts.
Add essential oils 1-2.5% (relative to the total weight of the oils) to your soap.
Honey: liquid honey (moisturizing, softening). Be careful, honey tends to speed up the trace use up to 2%.
Oat powder: very appreciated by sensitive skin, to be incorporated at the time of trace.
Milks: this provides a very mild skin soap with a creamy, soft texture.
Exfoliates: mashed fruits or vegetables: carrot, avocado, banana..
Dried Flowers and Plants.
The Best Recipe for making soaps!
The amount of oil is 2000g:
70% olive oil.
30% coconut oil.
Over-fat 2% castor oil.
Calculates the amount of oils and lye (NaOH) and water (H2O) and over-fat:
Oil Calculator —– NaOH Calculator —– H2O Calculator —– Over-Fat
Olive oil: 70*2000/100 =1400g. 1400g*0.135=189g.
Coconut oil: 30*2000/100 = 600g. 600*0.184=1104g
Naoh: 189+110.4= 299.4g! Let’s round that up to 299g.
Let’s round that up to 748g
Castor oil: 2*200/100=40g.
Preparation of the recipe:
1. Measure the water and put it in a glass or hard plastic jar. Be careful and do use gloves and goggles.
Measure the lye and pour the lye into the water (not the other way around).
Then mix until dissolved. Put the glass jar in a water bath of cold water to lower the temperature.
2. Weigh the coconut oil and melt in a double boiler and place in a container.
3. Weigh the olive oil and add it to the coconut oil.
4. Weigh castor oil.
5. When the temperature of the lye and oils is 35-40°C, pour the lye solution into the oil and add it to the mixture. Mix everything with a dip blender until you get the «trace» (the trace is the consistency of thick custard), in this moment add the castor oil.
6. Pour into the mould.
7. Let the soaps sit for 48 hours in a dry place, unmould and cut by hand, let them dry for 4 weeks.
The soaps can be stored safely for months to years in a dry, well ventilated place away from light and heat.
Natural ingredients are better for the skin overall if you choose the right products for your skin needs. Chemicals can cause skin irritation while natural skincare products are gentler on the skin. There are no harmful chemicals released during the creation of these products!
Thank you for learning and reading here, please leave a comment or questions below and I’ll be sure to help you out:)