Oil selection is the number one principal to understand and apply to your liquid soap making project. The oils used will determine the character of your soap. Make it lather well or not. Moisturizing or drying to the skin. Determine it’s clarity or cloudiness. The cost of your project will be significantly affected by the oils used. Organic is more costly than non-organic, exotic oils are rare and more costly than widely available oils. As always the choice is yours as to what oils are used in your project.
But there are some important concepts that need to be addressed in order to produce a liquid soap. If crystal clarity is not your ultimate goal, then your choice of oils can be a little more lax. Some oils though, do not lend them selves to liquid soap making. Oils that cannot be used exclusively to produce a liquid soap are; lards, animal fats, they have particles that will not sapaonify, leaving the liquid soap milky, cloudy and causes separations within the soap. Waxes and butters, cannot be used exclusively, they also have constitutients that will not completely saponify. Causing clouding and milkiness of the soap. Maybe useable, but does take away from the beauty of the soap. If waxes, such as jojoba oil, and butters, such as cocoa butter, lanolin and shay are used, they would be a very small percentage of the formulation to prevent clouding of the finished product. Unlike hot process soap making where hard fats, lard, coconut oil, palm kernel oil, etc, are used extensively. To harden the bar, make it more moisturizing and for superfatting. These fats and oils are used in moderation or not at all in liquid soap making, with the exception of coconut oil. Coconut oil is the backbone of liquid soap making, it will be used in almost any liquid soap formulation you make. Why Is Coconut Oil So Popular In Liquid Soap Making? Lauric acid, the principal fatty acid found in coconut oil. Lauric acid is very soluble, makes a great lather with a long shelf life. Coconut oil saponifies quickly, making it easy to work with and produces a crystal clear liquid soap that lathers well. Due to it great solubility, it can produce a thicker liquid soap as it requies less dilution to create a liquid. As with all good things there is always a downside or less desirable element. Coconut oil tends to be drying to the skin. Also it will not thicken significantly with the addition of borax and can cost more than other common oils. So what to do, have a soap with weak lather, but is gentler to the skin? The solution it to combine oils to give your soap the desired qualities. This leads us to the two primary classes of oils, “hard fats and soft oils.” Hard fats are considered solid at room temperature; such as coconut oil and palm kernel oil or flakes. These oils are highly soluble, easy to work with and produce a very good thick, lasting lather. Tend to have a longer shelf life and does not get rancid as quickly as soft oils. The downside or less desireable elements of hard fats are they can cloud the soap at high percentages of the formula due to high levels of substances that do not saponify and can be drying to the skin. Soft oils are considered liquid at room temperature; olive oil, sweet almond oil, canola oil, etc. They have a shorter shelf life, best to keep refrigerated. Not as soluble as hard fats, but do provide moisturizing properties and make great shower gels. Combining the two classes of oils will give your soap the desired qualities of clarity, great lathering ability and moisturizing properties. How to know how much to use of each type of oil? This is the million dollar question, and that depends on what type of liquid soap you wish to make. Examples: Shower gel – is best when using a high percentage of soft oils in the formulation, such as 95% olive oil and 5% coconut oil. Will give a nice thick soap that lathers well and provides exceptional moisturizing properties. Hand or dish soap – best using a 50/50 formulation. 50% hard fats and 50% soft oil. Will lather well, and provide a stronger cleaning soap. Bubble Bath – What makes a bubble bath a bubble bath? Bubbles! How do you create mounds and mounds of bubbles? With coconut oil….a formulation with 95% coconut oil and 5% soft oil will produce the best bubble baths. Combined with other additives and a combination of lyes to increase the density of the bubbles. These are examples of the thought process that goes into selecting oil combinations for your liquid soap projects. They are just guidelines and rather simplified, but it gets the point across of how the oils you select will contribute to the qualities you want your liquid soap to have. Can Liquid Soap be Superfatted? Yes, but is is more challenging than with bar soap. There a very few oils which can be used to superfat liquid soap. Most oils will cloud and cause separation of the finished soap. The best and really only oil which can be used as a superfatting agent in liquid soaps is Sulfonated Castor Oil, (Turkery Red Oil). It is very soluble, will not cloud or separate the soap and provides added lubricating properties. I use it rarely, as my soap formulations are quite moisturizing as they are. But if you wish to use it, it is added after the soap has been diluted, used at a rate of 1 to 2 oz to the finished soap, while it it still hot. Fatty Acids Are The Key The fatty acids that comprise each oil are the constitutents that give each oil their own unique properties. Such as lauric fatty acids in coconut oil. Making coconut oil quite soluble and easy to work with. Oleic acid in olive oil, giving olive oil it moisturizing properties and good for the skin. Linolenic acid in safflower oil, giving the lather body and making it a good choice as a shower gel. This link takes you to a discussion of fatty acids and what qualities they lend to your liquid soap. http://www.modernsoapmaking.com/the-most-popular-fatty-acid-profiles-in-soapmaking/ We can thank Kenna of “Modern Soap Making” for this valuable information. This section has discussed the importance of oil selection to determine the qualities you want your liquid soap project to have. It is just the tip of the iceberg as an entire book could be written on oils and their properties and what qualities they can lend to your soap making formulations.