Fatty Acid Composition of Oils

Fatty Acids, Part 2

Here is a list of oils commonly used in soap making, their major fatty acid make up and contribution to the finished properties of soap:

Almond Oil:  Very high in oleic acid, so it contributes conditioning properties.  Low to moderate amount of linoleic acid, so don't use large amounts to avoid rancidity and DOS.

Avocado Oil:  High in oleic acid, moderate amount of palmitic acid, and low to moderate amount of linoleic acid.  Good conditioning, contributes a bit to hardness.  Don't use in large amounts to avoid DOS and rancidity.

Canola Oil:  High in oleic acid with a moderate amount of linoleic.  While conditioning, this oil would make soap prone to DOS and rancidity. Very little saturated fatty acids, so it will contribute to a soft bar of soap.

Castor Oil: Extremely high in ricinoleic acid, so it adds much conditioning and fluffy lather properties.  Contains no saturated fatty acids, so too much will make a soft, sticky bar of soap.

Coconut Oil:  Moderate amounts of saturated fatty acids, so it contributes to a hard bar of soap. High in lauric acid, which contributes to a rich, fluffy lather. Low to moderate amount of oleic acid.  The amount of saturated fa;tty acids mean that generally speaking, the more coconut oil in the soap, the more drying it will be.

Cocoa Butter: Total amounts of fatty acids are high (palmitic and stearic).  Would make a hard bar of soap with good conditioning due to the oleic acid.  Similar to lard. 

Crisco:  Moderate amounts of palmitic acid, with some stearic acid, so it will contribute to a harder bar. High in oleic, so it is also a bit conditioning. Moderate amount of linoleic, so too much will make the soap prone to DOS (it happened to me!).

Grapeseed Oil: Very high in linoleic acid, so more than a token amount will make the bar very prone to rancidity and DOS. The amounts of other fatty acids don't make up for the large amount of linoleic, so I'd stick with bath and body products for this one. 

Hemp Oil:  Very similar to grapeseed. Very high in linoleic acid, so it will tend to go rancid and promote DOS.  Even less of other fatty acids than grapeseed, so there is little to recommend it for soap.

Jojoba Oil:  The only fatty acid in joboba oil is oleic, and there isn't that much to begin with, so unless you are using it as a superfatting oil (it is roughly made up of 50% unsaponifiables, so you could assume only half will react with the lye), there is little it offers to soap.

Lard:  High in saturated fatty acids, so it will produce a hard bar, and very high in oleic acid, so it is conditioning.

Mango Butter:  Very similar to lard in ratio of saturated to unsaturated fatty acids, so it would make a  good veggie substitute. Hmmm....will have to try that!

Olive Oil:  Very high in oleic acid, so it is very conditioning. Low to moderate amounts of palmitic (mostly) and stearic acid,  so it will not create a very fluffy lather.  Moderate amount of linoleic, which probably explains why some 100% castile soaps get DOS.


Palm Kernel Oil/Flakes:  You want fluffy lather?  This is the oil for you. Very high in lauric acid, with moderate amounts of myristic and palmitic acids. Moderate oleic acid as well.  Be careful of using too much or the soap may be drying.

Palm Oil:  Similar in properties to palm kernel oil, though the major saturated fatty acid is palmitic acid, not lauric acid. High amounts of oleic acid, so it should be more conditioning than PKO. Low to moderate amount of linoleic acid.

Rice Bran Oil:  This is an interesting oil.  Moderate to high amount of palmitic acid, so it would contribute to a harder bar, very high in oleic, so it is conditioning as well, but unfortunately also moderately high amount of linoleic acid, so unless used in tiny amounts, it should promote DOS and rancidity.

Safflower Oil:  Extremely high in linoleic acid, with little else in its favor.  Just avoid it, unless you want to use it in bath and body products.

Shea Butter:  Very similar to mango butter, so therefore a good veggie substitute for lard. High in stearic acid (hard bar), and oleic acid (conditioning). A tad more linoleic acid than mango butter.

Soybean Oil:  Another one very high in linoleic acid.  Stick to bath and body products for this one.


There are many other oils out there, and Soapcalc has lots of other oils in its database.  Feel free to use the information from my last two blog posts to determine the contributions some of the more esoteric oils would make to your soap. Use this information, and Soapcalc (or other lye calculator), to develop soap recipes that make a soap with YOUR desired properties.  That's the art and science of making soap!

Feel free to copy and paste this information for your use, but please reference this page as your source.

Oil fatty acid compositions found at www.soapcalc.net

Fatty Acids in Soap

There are so many different oils we can use to make soap, choosing which oils to use in a new recipe can get really confusing to the newbie soapmaker (and some of us who've been around the block a couple of times too!).   Soapcalc (my favorite lye calculator, and topic of a future post), lists the fatty acid make up of all the oils in its database.  However, unless you know what each fatty acid brings to the party, the information is only so helpful.  Soapcalc does list the hardness, cleansing, conditioning, and lather properties of each oil. However, I find that as I develop new recipes to try out, I'm looking more and more often at the amounts of specific fatty acids in my oils, because I want to increase or decrease specific properties in my soap.

This post will describe the different fatty acids found in soap, and how they affect the properties of our finished soap.  The next post will look at some of the more common oils we use in soap making, and the major fatty acid make up of each one. I'll start by explaining some basic chemistry of fatty acids.  If high school or college chemistry gave you a headache, feel free to skip this next paragraph and go right to the list of fatty acids found in our soap making oils.

What IS a fatty acid?  As the name implies, it is both a fat and an acid.  The head of the molecule is a carboxylic acid,  and the tail is a chain of carbon and hydrogen atoms of varying length. There may be some double bonds between the carbon atoms, making the fatty acid unsaturated, or there may be no double bonds, making it saturated (it has as many hydrogen atoms attached as is possible). The number and location of the double bonds contributes to the flexibility of the molecule, and the melting temperature of the oil.  A non-scientific way of determining the relative saturation of oils is to see how solid the fat is at room temperature.  The more solid the fat, the fewer double bonds it has. Saturated fatty acids (like stearic acid and palmitic acid), are quite hard at room temperature, and have high melting temperatures, while highly unsaturated oils (like olive oil), are liquid at room temperature, and stay liquid until they get fairly cool.  Because of saturation/non-saturation, one can see that the more saturated the fatty acids in the oils and butters you use, the harder the finished bar of soap will be.  Unsaturated oils will add more conditioning properties to soap.

Fatty Acids Found in Soap and Their Properties

• Lauric Acid:  A saturated fatty acid that contributes to a hard bar, fluffy and stable lather, and high cleaning. Too much of this fatty acid can make a soap drying.
• Linoleic Acid:  An unsaturated fatty acid adds conditioning to the soap.  Oils high in this fatty acid tend to go rancid quickly, and more easily develop DOS (dreaded orange spots).
• Linolenic Acid:  Not to be confused with linoleic acid.  Adds conditioning properties and is very mild. 
• Myristic Acid:  A saturated fatty acid, so it adds to the hardness of the bar, fluffy lather, and cleansing ability.  Soaps high in myristic can be very drying to the skin.
• Oleic Acid:  An unsaturated fatty acid, so it adds conditioning properties.  This fatty acid does not contribute much to the lather of a soap, but it does contribute to the "slippery" feeling of soap.
• Palmitic Acid:  Another saturated fatty acid, so it will contribute to a hard bar and can by drying if too much is used.  It contributes to a creamy, rather than fluffy lather. 
• Ricinoleic Acid:  Unsaturated, it adds conditioning properties, and is great for a fluffy, bubbly lather.  Found almost exclusively, and in great quantities in castor oil. 
• Stearic Acid:  Saturated, so it contributes to a hard bar. It is very similar to palmitic acid, and is generally interchangeable with it.  Contributes to a creamy lather. 

Feel free to copy and paste this information for your future use. However, please reference this page as your source. 


A list of my sources of information: 
Wikipedia entry on fatty acids
Wikipedia entry on carboxylic acids
Wikipedia entry on ricinoleic acid
Buzzle article on fatty acids
Fatty acid information