Oleic, Lauric and Lye Concentrations

[KiwiMoose]

Hi,

I've been doing a bit of research into the types of fatty acids and their purpose. It seems that oleic and lauric are the ones that hold the fort in terms of higher percentages, while the others appear in lower percentages varying between 0 -15% each.

I found a good article about fatty acids profiles online:
the-most-popular-fatty-acid-profiles-in-soapmaking

My question is - are there guidelines on how the lye concentration might increase or decrease according to the percentages of the different fatty acids? And, if so, why this is so? Or is completely arbitrary?

 

[DeeAnna]

Not sure why you're putting lauric acid in the higher-percentage category. It looks to me like palmitic and oleic are the fatty acids (FAs) that have the highest percentages in soap per Kenna's charts. That makes more sense to me based on what I see in most soap recipes.

IMO, it can be more useful to group the straight-chain, saturated FAs into pairs rather than look at them individually, because that's how these FAs are supplied by the common soaping fats.

Coconut, palm kernel and babassu are rich in lauric and myristic, the FAs that make highly soluble, hard soap with fluffy lather. Lauric acid and shorter-chain FAs also can be drying and sometimes irritating to the skin, especially sensitive skin.

Lard, palm, tallow, and the butters are rich in stearic and palmitic, the FAs that make low solubility, hard soap with dense lather. Even the typical commercial "stearic acid" that many people use to make lotions and shave soaps is actually a blend of stearic and palmitic, not pure stearic.

The unsaturated FAs don't pair up, so it's useful to look at them separately. First are the mostly monounsaturated fats rich in oleic acid -- olive, avocado, etc. -- which make high solubility soap with dense lather.

Next are the mostly polyunsaturated fats rich in linoleic and linolenic acid, -- hemp, grapeseed, pumpkin seed, etc. -- which also make high solubility soap with dense lather. Compared with monounsaturated FAs, these fats have a shorter shelf life.

And finally castor oil, a monounsaturated FA with an alcohol (OH) group, which contributes ricinoleic acid that enhances lather stability.

***

The lye concentration is not arbitrary. Higher lye concentration (less water, lower water:lye ratio) works better for fats high in oleic and linoleic acids. Lower lye concentration (more water, higher water:lye ratio) works better for fats high in lauric and myristic acids.

There are no black-and-white numbers to use, however, because the lye concentration that works best doesn't depend on just the FAs in the soap. It will also depend on the amount of stick blending you do, the starting soap batter temperature, how you treat the soap when its saponifying in the mold, the use of additives including fragrances and colors, what decorative swirls you do (or don't do), etc.

An article I wrote: https://classicbells.com/soap/waterInSoap.html
An article by Roberto Akira: http://www.japudo.com.br/2013/05/14/the-importance-of-lye-concentration/

 

[KiwiMoose]

Thanks DeeAnna,

I think I have lauric a bit higher in mine due to the coconut oil I use as a base. Usually 25%. Oleic is high due to the use of EVOO and Castor Oil. And maybe apricot kernel oil? My other oil of choice.

A few things I like to steer clear of in my house:
Palm Oil - due to sustainability issues, whether or not I buy from a sustainable source, people just don't like the name 'Palm'. We don't use it in NZ for very much at all. We don't have 'crisco' here.
Animal Fats - even though I eat animals I don't want to use them in my soap.
Canola Oil, Sunflower Oil, Rice Bran Oil - my partner for nutritional reasons wont touch these oils because they are trans fats.
Avocado Oil - I am planning on making soap for my dogs and avocado oils is a no-no for dogs.
Nut Oils - my son is allergic to nuts, otherwise I probably would have used almond oil as one of my commonly occurring ingredients.

I'm going for combinations of Coconut, EVOO, Apricot kernel, Castor and Shea Butter in smaller quantities. Is there anything else that i could put in there to bring up the Palmitic?

I find all this very interesting. My niece asked if she could make some soap, and I said no, it's very complicated and sometimes dangerous. Now I am reading more about cure times too, and wondering where on earth I'm going to house all my curing soap (given that I can see myself making a batch every weekend now)!

Your water/lye article look interesting, I'll head there now and have a read.

 

[shunt2011]

Just and FYI Avocado oil is fine for dogs. They just should not have the pits, skin, leaves or stems. I've given my dogs food cooked in avocado oil for years with no issue and researched it heavily before doing so. Also, Avocado oil is a different thing once turned into soap.

You may want to do some reading on oils and what they are once put in soap. You will be much better informed. Coconut is great for the skin until in soap. Conditions in it's natural state, strips the skin of natural oils in soap.

Washing animals with soap on occasion may be okay but otherwise the PH is too high for their skin if used frequently.

 

[Dean]

Thanks DeeAnna,

I think I have lauric a bit higher in mine due to the coconut oil I use as a base. Usually 25%. Oleic is high due to the use of EVOO and Castor Oil. And maybe apricot kernel oil? My other oil of choice.

A few things I like to steer clear of in my house:
Palm Oil - due to sustainability issues, whether or not I buy from a sustainable source, people just don't like the name 'Palm'. We don't use it in NZ for very much at all. We don't have 'crisco' here.
Animal Fats - even though I eat animals I don't want to use them in my soap.
Canola Oil, Sunflower Oil, Rice Bran Oil - my partner for nutritional reasons wont touch these oils because they are trans fats.
Avocado Oil - I am planning on making soap for my dogs and avocado oils is a no-no for dogs.
Nut Oils - my son is allergic to nuts, otherwise I probably would have used almond oil as one of my commonly occurring ingredients.

I'm going for combinations of Coconut, EVOO, Apricot kernel, Castor and Shea Butter in smaller quantities. Is there anything else that i could put in there to bring up the Palmitic?

I find all this very interesting. My niece asked if she could make some soap, and I said no, it's very complicated and sometimes dangerous. Now I am reading more about cure times too, and wondering where on earth I'm going to house all my curing soap (given that I can see myself making a batch every weekend now)!

Your water/lye article look interesting, I'll head there now and have a read.

Palm provides hardness. You will have to use a lot of shea for hardness. Soy wax (100% hydrogenated soy bean oil) is a palm alternative. Do you have that in NZ? If not, can you get it from your Aussie cousins? Cocoa butter will provide hardness too. Butters are more expensive than soy wax. Rumor has it that the butter unsaponifiables will dampen lather. Refined butters have less.

 

[KiwiMoose]

Thanks Dean. Yes we can get soy wax here and it seems very reasonably priced. However, I’ve only found it in candle making sites. Is this the same type that is used for soap making, or do I need a specific kind of soy wax?

 

[cmzaha]

Just and FYI Avocado oil is fine for dogs. They just should not have the pits, skin, leaves or stems. I've given my dogs food cooked in avocado oil for years with no issue and researched it heavily before doing so. Also, Avocado oil is a different thing once turned into soap.

You may want to do some reading on oils and what they are once put in soap. You will be much better informed. Coconut is great for the skin until in soap. Conditions in it's natural state, strips the skin of natural oils in soap.

Washing animals with soap on occasion may be okay but otherwise the PH is too high for their skin if used frequently.

Dogs love avocados and our dogs never swallowed the pits. We had a coyote and Norwegian Elkhound, they would lay under the avocado trees waiting for them to fall. Did not matter that they were not ripe. They also had beautiful coats from getting to also eat ripe avocados that we would add to their food a couple times a week while the avocados were in season

 

[Dean]

Thanks Dean. Yes we can get soy wax here and it seems very reasonably priced. However, I’ve only found it in candle making sites. Is this the same type that is used for soap making, or do I need a specific kind of soy wax?

It comes in different grades...some with additives that u dont want in soap. I use 415 SW as recommended by SMFers. Google it.

 

[KiwiMoose]

It comes in different grades...some with additives that u dont want in soap. I use 415 SW as recommended by SMFers. Google it.

Thanks again Dean - I found it for jus $NZ12.50 per kg! That's only about $US7
It seems that it's not usually used in soap here - pretty much only the candle suppliers use it. It says its melt point is around 48 - 50 degrees celsius so I wonder if I would need to mix my lye water and oils at a slightly higher temperature than I usually do (lol - get her - only made two batches so far).

 

[Dean]

Thanks again Dean - I found it for jus $NZ12.50 per kg! That's only about $US7
It seems that it's not usually used in soap here - pretty much only the candle suppliers use it. It says its melt point is around 48 - 50 degrees celsius so I wonder if I would need to mix my lye water and oils at a slightly higher temperature than I usually do (lol - get her - only made two batches so far).

I dont worry bout temps. I melt CO, add it to the SW, microwave until SW is fully melted wo stirring, add refrigerated liquid oils to cool it dn. Liquid for lye sol is 1/2 frozen or all refrigerated. I put the filled mold in the freezer for one hr to prevent partial gel.

U may want to do test batches. I like experimenting and the soap is just for me so I make two bars at a time....enough soap to use a SB. That means I can make soap every cpl wks or so.

 

[SaltedFig]

A few things I like to steer clear of in my house:
...
Canola Oil, Sunflower Oil, Rice Bran Oil - my partner for nutritional reasons wont touch these oils because they are trans fats.
...

... we can get soy wax here and it seems very reasonably priced. However, I’ve only found it in candle making sites. ...

I'm not sure whether you/your partner is won't use all partially hydrogenated fats or just the dietary trans fats, so I thought it worth mentioning that this soy wax is made from partially hydrogenated soybean oil (which is how it is transformed from liquid soybean oil into soy "wax").

The manufacturer is AAK, and they make the "Golden Wax" brand of soy waxes (GW in GW415 stands for Golden Wax) as a candle wax.
Your distributor's/supplier's MSDS for the product will list the single ingredient as "partially hydrogenated soybean oil".

As the product is listed as a candle wax, it may not have been tested for use in skin products by the manufacturer.
It is not stated directly, one way or the other, but it is also highly likely that the source material (soybean oil) is made from GM soy - there is no legal requirement to note this in candle wax products.
These points may only become relevant if you intend to sell or donate your soap (for personal use it's up to you).

Soy wax will add the hardening quality to soap as a cheaper substitute for natural hard fats and butters, just as described.

 

[KiwiMoose]

Thanks SaltedFig. The GW is the one I can source here - it comes in flakes. Might give it a go. Hubby doesn’t like Soy either because it’s mostly genetically modified. I just won’t tell him

 

[earlene]

There are a couple (or more) SMF soapers here who use Soy Wax in most of their soaps. I learned about it here. The amount I use tends to be about 30%. I suggest you make a couple of test batches with different percentages to see what you like.

Olive oil will give you a very hard bar of soap, but a 100% OO soap requires a very long cure, so storage can be an issue. But I like making Castile soap once or twice a year and keep a nice supply rotating through the cure.