Oil Properties - Beyond the 8 Fatty Acids

[dougsfarm]

I am trying to get a deeper understanding of oils and their properties. Most of the internet explains oil properties as follows:
- There are 8 different fatty acids (Lauric, Myristic, Palmitic, Stearic, Ricinoleic, Oleic, Linoleic, Linolenic).
- Each of these fatty acids has certain characteristics (hardness, cleaning, bubbly lather, creamy lather, conditioning).
- For a given oil, one can know its characteristics by first looking at which of the 8 fatty acids it contains and in what ratio, and then looking at the properties of these oils. For example, coconut oil is mainly Lauric and Myristic, which bring hardness, cleaning and bubbly lather.

Although I think the above explanation is a good start, it is apparent that it misses out a lot. For example, shea butter has about 10% unsaponifiables and jojoba oil can be around 50% unsaponifiables. I hear a lot of experienced soap makers talk about how great these oils are and that they bring something special to the soap. However, I am still looking for someone to describe what this special something is and how it differs from other oils (or oil combinations) with a similar profile in terms of the 8 basic oils. Likewise with avocado oil (up to 10% unsaponifiables).

Another example is Meadowfoam oil, which is similar to jojoba oil in that it consists mainly of Eicosenoic acid. This is not even in the list of soap making fatty acids. Likewise, Docosadienoic acid, which makes up about 18% of Meadowfoam oil.

Another example is that there are four fatty acids (Ricinoleic, Oleic, Linoleic, Linolenic) which contribute conditioning. However, they differ in terms of the ease with which they are absorbed into the skin and the extent to which they condition.

Consequently, I feel that the traditional explanation (8 different fatty acids and the associated 5 characteristics) leave a lot out. Would love to hear from anyone who can provide more detailed information, either in terms of specific oils or in more general terms.

 

[LunaSkye]

I have not experienced the same problem, but I think your results may differ if you look for oil properties in terms of how it works on the skin or in the hair. That's what I do when I need more information on the type of oils I want to use.

 

[dougsfarm]

Opportunity to be better

I have not experienced the same problem, but I think your results may differ if you look for oil properties in terms of how it works on the skin or in the hair. That's what I do when I need more information on the type of oils I want to use.

LunaSkye,

For me, it is not so much a problem as an opportunity. I can make good soap, using the basic information. However, I think there is an opportunity to make better soap if there was more information along the lines of my original post.

As a side note, I have heard some people state that the oil properties are different in lotions than in soaps. For example, that the extra moisturizing properties of Shea makes a much bigger contribution in a lotion than in a soap.

Your comment on skin versus hair is also very interesting and worth exploring as part of a deeper understanding of oils.

 

[LunaSkye]

@dougsfarm: Now I understand where you are coming from a bit more, but I don't think I can add anymore suggestion than what I just said. Some sites have whole articles written on different oils and how they can benefit the skin, hair, etc. Livestrong.com is one of those sites.

If there is any information I would love to find (I haven't gotten around to looking yet) is what happens to the benefits of an oil as it heats up. Are some of them destroyed by the heat? At what temperatures will the oils start losing their benefits? I've been curious about this for some time.

 

[dougsfarm]

I have looked at various sites which posted on the benefits of oils. However, I disagree with much of what is written. In fact, I consider much of it to be misleading marketing hype.

In particular, I disagree with descriptions which talk about the benefits of vitamins. Sure, many oils contain lots of vitamins and if you were to drink them, then they could be quite beneficial. However, after the oils have been heated, then converted to soap and then stored for months, I seriously doubt that much is left from the original vitamins.

Of course, in a lotion, more vitamins may survive, but even here I doubt that much is absorbed through the skin in a way which the body could use. If the body could absorb nutrients in this way, one would only need to stick a hand in a glass of orange juice rather than having to drink it.

One could go through the other claims of oil benefits and I think find many of them either untrue or exaggerated. I think the basic claims (e.g. cleansing, lather) are reliable. Even the oils which are described as moisturizing I think can only exhibit this property either in a non-soap form or in the SF part of a soap; within a soap the more accurate description would be non-drying.

 

[jade-15]

Have you looked at http://swiftcraftymonkey.blogspot.com.au/ at all?
She goes into depth about varying oil properties, and explains some fatty acids (linolenic, oleic etc). She doesn't do soap though, so the info is mainly of use in lotions/hair products but you might find it interesting. She also has plenty of links that may prove to be useful.
But I agree with you on the vitamins etc for soap - most of it is just label appeal. Even as a soap maker if I read a description like "green tea and lemongrass" I think it sounds amazing... Despite knowing that using green tea in place of water doesn't seem to make any difference in my soaps!

 

[Susie]

I have nothing to add on the scientific end of your inquiries. However, I can truthfully say that you will never really know what oils such as jojoba, meadowfoam, or butters such as shea will bring to your soaps until you try them. Some things are going to depend on what qualities your soap already has, some are going to depend on your personal preferences.

 

[dougsfarm]

Have you looked at http://swiftcraftymonkey.blogspot.com.au/ at all?
She goes into depth about varying oil properties, and explains some fatty acids (linolenic, oleic etc). She doesn't do soap though, so the info is mainly of use in lotions/hair products but you might find it interesting. She also has plenty of links that may prove to be useful.

JADE-15,

Thank you for the link!!!!!!

Agreed that the blog is mainly from the lotions perspective. However, tons of useful base information, some of which I can use and some of which is just fun to know. I also like very much the way she presents pros and cons in a balanced and honest way. Also, if I ever expand into lotions, this will be my first start.

 

[green soap]

I really like these types of questions because it makes us think outside the box (soapcalc box??? LOL) The 8 main fatty acid information has served me well to make bar soap, with a couple of exceptions.

For example, cocoa and shea butters are similar in their fatty acid profiles, so they can substitute each other in soap. I use these butters because i do not use AOs or palm, and their stearic acid content provides hardness and creamy lather, making for a soap with 'perfect' characteristics as per soapcalc.

Things about them NOT included in their fatty acid profiles: shea is non comedogenic and cocoa is highly comedogenic, so in a soap targeted for acne sufferers one would chose shea. (Just thinking of the super fat here).

I have not been finding deodorized cocoa butter, and the cocoa scent came trough in a couple of soaps I made, even at a low CB usage. The added scent messed up my EO scent blend. In other soaps I do like the residual cocoa scent because it blends well with whatever EOs I am using. Scent is not part of the fatty acid description but it is important in soap.

Another area where the 8 fatty acid description is incomplete is liquid soap. Here you want as low a stearic acid number as possible, since stearic acid makes clear liquid soap harder to achieve. Speaking of avocado and unsaponifiables, once I tried avocado oil in liquid soap (it has low stearic acid content) but the non saponified part made my liquid soap cloudy and it never cleared for me.

Another example is the capric caprylllc acid in goat's milk. A very short chained fatty acid (shorter than lauric) I suspect it contributes hardness and lather to my castile goat milk soap (some would consider a bastile).

As far as lotions go, again shea and cocoa butter behave very differently. Shea has an annoying tendency to get grainy (cool fast if this happens) and cocoa never does. Yet, shea is non comedogenic and cocoa is. Neither is part of the 8 fatty acid description though, but good to know. I realize the soapcalc type approach is for soap only, so it is good to read other descriptions of the different oils before lotion making.

Another comment on the unsaponifiables in avocado. I have been making a version of Jenny's shampoo bars (minus the soy and more avocado) and they are great. I have not made a soap with a similar fatty acid profile and no avocado, so I do not have a control here, all I know is that the avocado oil makes the shampoo bars great, at least for my hair.

Just few examples for you, I'll add more if I think of more.

 

[The Efficacious Gentleman]

We must take care, however, to be accurate on what properties an oil has once it is a soapy salt. My favourite example is coconut oil, which is lovely and moisturising as an oil but then is very drying as a salt, once it has been saponified.

What properties an oil has may not always translate in to the soap-version.

 

[green soap]

We must take care, however, to be accurate on what properties an oil has once it is a soapy salt. My favourite example is coconut oil, which is lovely and moisturising as an oil but then is very drying as a salt, once it has been saponified.

What properties an oil has may not always translate in to the soap-version.

So true! and coconut oil is a good example. Also why it works so well with its own high super fat. 100% CO with 20% SF is a fairly mellow soap.

This concept confuses my customers though. Trying to figure out a good way to explain it so it does not leave them even more confused.