Why does 100% coconut oil soap work?

[FragranceGuy]

I’m planning to make a batch of pure coconut soap. A lot of people seem to enjoy them, but the numbers are all over the place and I’m confused as to how it makes such a good bar of soap. It’s seems that most people agree that it requires a high SF (20%) and that makes total sense as a way to offset the super cleansing qualities of coconut oil. But what about the INS? It’s through the roof! And virtually no iodine? The hardness value is high, but longevity low? It seems like one big paradox. I’m curious what is being sacrificed. How does it cure? Is it prone to DOS?
Thanks!!

 

[Ford]

I cut my 75 percent CO bars at 4-5 hours. And they heat up pretty good as well. No sure of your other questions. Just a newby myself.

 

[KiwiMoose]

Same with 100% OO soaps. Most single oils will work, but the numbers don't add up.
With 100% CO it makes a hard bar but, yes, the longevity is low because it's so sudsy that it uses up lots of soap at each wash.
Try using a brine solution or sea water maybe?

 

[penelopejane]

I find 100% CO drying for my skin and a bar lasts about a week. I use soap directly on my skin not on a washer so that might make a difference but boy they dissolve fast even after a really long cure unless they are a salt bar and then they last a little longer.

 

[FragranceGuy]

Thank you all! I’m going to put 100% CO on the to do list, but will probably experiment with 3 oil soaps for now.

 

[cmzaha]

100% CO soap does not last long because it is a high soluble soap which is why it lathers easily, it is also why it lathers in saltwater and is considered a Sailer's Soap.

 

[DeeAnna]

INS and Iodine Number are more useful if you are making soap commercially where production speed and volume and product consistency are critical. They are not as useful when making handcrafted soap.

It's perfectly okay to pay attention to these numbers because they are informative regarding the level of saturation versus unsaturation of the fats. That said, I wouldn't put a large amount of weight on these values when designing a recipe for handcrafted soap.

I have the same advice about the saturated:unsaturated ratio shown in some soap recipe calcs -- it's telling you roughly the same info as INS and Iodine Number. Informative, but not critical.

 

[FragranceGuy]

Thanks! @DeeAnna I’ve noticed some talented soapers pay close attention to INS and others don’t. Lately I’ve been developing recipes with lard and my iodine and INS levels fall into range much easier than when I’m working with crisco and less expensive vegetable oils. I’ll take that as a good sign, but I won’t let bad numbers scare me away from trying a recipe. It’s my understanding that lower INS takes longer to cure, which makes sense because Castile soap has a low INS. Some people say a high iodine value causes their skin to itch. Have you noticed any correlations with soaps where the iodine and INS are out of typical range? Thanks again

 

[Mobjack Bay]

not DeeAnna, but the drying issue correlated with higher iodine seems counterintuitive. Unsaturated fats have higher iodine values than saturated fats. Many of the oils that are highly valued for skin care, like argan, evening primrose and rosehip, are very high in polyunsaturated fats. Using one or more of these oils or oils high in monounsaturated fats, like olive or sunflower, to replace some of a mostly saturated fat in a soap recipe would result in a higher iodine value. Some folks on the forum have mentioned that they find olive oil drying, but I’ve always assumed it must be due to something other than the oleics in the OO. Many other fats, including lard, have oleics.

 

[DeeAnna]

INS is equal to the Saponification Value minus the Iodine Number. INS was originally developed as a quick check to identify blends that saponify easily and make a hard soap suitable for high volume processing and packaging. INS is honestly not a number you can use to predict the time to cure -- I can't quite see where that idea is coming from based on my understanding of how INS is calculated. If this idea is correct, then coconut oil soap should cure in a flash, and I know CO soap doesn't cure any faster than other typical soap does. Remember -- curing is not relevant to commercial soap production -- commercial soaps aren't cured for weeks like handcrafted soap normally is.

The Iodine Number is the result of a chemical test that measures how much of a particular iodine solution reacts with the fatty acids in a particular fat or blend of fats. The Iodine Number indicates the amount of of unsaturated fatty acids present. Soap made with mostly unsaturated (liquid) fats will tend to have a high Iodine Number and soap made with mostly saturated (solid) fats will have a low Iodine Number.

I have no idea what a "typical" range is for INS and Iodine Number. These are broad-brush measurements that are used to evaluate fat blends for commercial production, and I don't find either one particularly useful when evaluating a fat blend for making handcrafted soap. I am far more interested in looking at the fatty acid profile -- that information is more nuanced and useful.

 

[FragranceGuy]

@Mobjack Bay @DeeAnna Thank you both SO much for taking the time to give me such detailed and informative responses! Understanding how and why things work helps me with creativity. As a musician I was never satisfied with “I like this song.” I always wanted to know “Why do I like this song and why don’t I like that song?” Having a better understanding of the science and qualities these values represent is going to help me tremendously. I think it’s time I start studying fatty acids I’m beginning to realize that soap theory seems a lot like music theory. If you follow the standard guidelines you’ll probably create something that’s inoffensive, but not necessarily good. It took me years of playing other people’s music before I developed an instinct for what moves me and what doesn’t. I break the “rules” whenever I want because if it work for me, then it works. I’m still a little shy of breaking soaping norms because I’m so green. I’m going to just keep making soap until I develop a similar instinct and HOPEFULLY make something truly great someday.

 

[DeeAnna]

I think beginners often need some black and white rules to get started. I found that to be true teaching math and science to college students and it seems to be true for newer soap makers too. Parents put training wheels on a beginner's bike, and take them off as the rider builds their skills.

Some of the rules that keep floating through the Forum seem to be rules specifically to simplify things for newcomers. Some examples -- The INS of the "ideal" recipe is 160. Fats and lye temps should be within 10 degrees F / 5 C of each other. Soap with "full water" because a "water discount" is only for experts. A 5% superfat is the lowest you should go for safety. Etc, etc.

When you rely on a single number -- INS or iodine -- to define a complex system, you're basically dumbing down the decision making process. That might be okay for a quick-and-dirty check or it might be good to help a beginner get started. But it's not good if you are trying to dig into the nuances of why one soap performs more better than another.

INS is the equivalent of playing a simple C major chord every time you see any chord that's based on the key of C.

I could create two recipes with the same INS number but using different fats. I guarantee even an average bather would be able to tell the two apart. One example would be a 100% lard recipe and the other would be a blend of 22% coconut and 88% olive.

The lard soap will last a long time, but it will produce smaller amounts of dense, long-lived lather. The coconut-olive soap will have a much shorter life in the bath but will produce a larger amount of fluffy lather.

I know this from experience, yes, but I can also tell this just by looking at the fatty acid profile. I can't tell this by looking at INS.

 

[FragranceGuy]

@DeeAnna I don’t think I’m alone when I say thank you for being so actively involved in this forum. As a beginner, I’m appreciative and eventually as an experienced soaper I’ll be appreciative. This is an excellent community to be a part of, thank you all for welcoming me.