Softness Solubility and Sodium Lactate

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boyago

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So El Sopa the soap spirit must have been whispering to me in my sleep again. Soapcutter had a bad dream and while I was getting her back to sleep I began wondering about soaps. Then after I started moving (and of course checked the forum forum) there was a kind of relevant thread. Maybe somebody has some insight on this stuff rattling around in my head.
So I am curious about the correlation between softness and solubility of soap. Is the a relevant marker for solubility?
Sodium Lactate will harden a bar up to 3% and then make it softer after that point will this also increase the solubility of soap? Does this also affect the lather do these factors impact lather much?
I'm thinking about this in relation to my shave soap. I have one that I love but it tends to lather a little slow and when you accidentally add too much water it takes even longer to coax it back to awesome.
 
I don't think that is always true. Look at coconut oil, very hard but also very soluble. I think DeeAnna explained it as the length of the soap fatty acid chains, or something like that, that determines how soluble or insoluble a soap will be.
 
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In SoapCalc, durability = hardness - cleansing.

So although olive oil isn't hard, it also isn't cleansing. Overall it's more durable than coconut (by the numbers), but of course it's also happy to absorb water just because olive is like that. :)

Generally, the more spare the lather, the more durable the soap will be. But there are still exceptions.
 
In SoapCalc, durability = hardness - cleansing.

So although olive oil isn't hard, it also isn't cleansing. Overall it's more durable than coconut (by the numbers), but of course it's also happy to absorb water just because olive is like that. :)

Generally, the more spare the lather, the more durable the soap will be. But there are still exceptions.

Wait, are we talking about hardness as in soap calc numbers or how physically hard a soap is, they are different things. Just one reason I ignore the numbers.
 
Wait, are we talking about hardness as in soap calc numbers or how physically hard a soap is, they are different things. Just one reason I ignore the numbers.

It seemed to be a solubility and durability question. Which I kind of didn't answer, so my bad.

Sodium lactate should make the soap feel harder...but since it's enhancing bubbles, I'd expect a bit less durability in the soap bar. It should dissolve faster.

I haven't tested it, but that's the working hypothesis given the effect.

Like you, I treat the numbers as a curiosity only...for the most part. I do pay some attention to them, but my favorite soap has a cleansing number of 3 with a hardness of a piddling 36.

By the numbers, it should be softer and not clean very well. In practice, it's hard as a rock, lasts ages, and cleans well enough to make me happy.
 
"....hardness as in soap calc numbers or how physically hard a soap is, they are different things..."

No, Dorymae, they're the same. Hardness in soapcalc is how hard the soap will be at unmolding -- meaning the physical hardness like a rock. It is somewhat but not entirely related to longevity. Hardness = % myristic + % lauric + % palmitic + % stearic acids in the soap.

"...By the numbers, it should be softer and not clean very well...."

Morpheus, I differ with your interpretation of the numbers for your soap. If it has a cleansing = 3 and hardness = 36, then it has a longevity factor of 36-3 = 33. This is telling you that a whopping 33% of your soap is made from palmitic and stearic acids, meaning this soap has relatively low solubility so it will last a long time and will be physically hard. And it will have dense creamy lather without many large fluffy bubbles.

I think the Soapcalc name of "Cleansing" is a poor choice of words, since your soap will clean your skin just fine. Until the Soapcalc folks change it, we're stuck with the name, unfortunately. It is actually a measure of the solubility of the soap in cold, hard, or salty water. Because Cleansing = % myristic acid + % lauric acid, it is also a measure of the aggressive nature of this soap to strip fats and proteins from the outer layer of the skin, since these short chain fatty acids have this ability that the longer chain fatty acids do not.

http://www.soapmakingforum.com/showpost.php?p=468038&postcount=10
 
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Thank you for clearing that up. At least now I know there is one number I can actually rely upon. I'm sure the numbers are accurate for what they actually mean, the problem is their descriptions are not always what I imagine them to be. Someday I really need to learn the makeup of the oils, but until then, thank you DeeAnna for setting me straight. :p
 
Morpheus, I differ with your interpretation of the numbers for your soap. If it has a cleansing = 3 and hardness = 36, then it has a longevity factor of 36-3 = 33. This is telling you that a whopping 33% of your soap is made from palmitic and stearic acids, meaning this soap has relatively low solubility so it will last a long time and will be physically hard. And it will have dense creamy lather without many large fluffy bubbles.

Unfortunately, that's why I don't trust the numbers. Mind, you could beat bandits to death with this soap when cured, so it's definitely very hard. The edges can actually be a little sharp at first.

In my case, I'm adding sodium lactate and honey to the recipe, so the bubbliness is far higher than you might expect. But even in this household, the bar lasts six days (by comparison, an MP bar will last four, Ivory about four).

Just a 1% modification in the recipe, not enough to imbalance the oils, is enough to change the soap into something different.

In this case, 75% of the recipe is olive oil, which gets a piddling hardness of 17 but can, when cured, be rock solid in and of itself. When dry, at least.

So while the numbers tell a story, they don't tell us the whole story.

I think the numbers are great, particularly for beginners who need some sort of a guide. Later on, they can be handy for a quick reality check, but the soap maker realizes that the actual soap, when made, may not quite be as they expect from the numbers--particularly when using additives.
 
So If I OD my shave soap with SL will it be more soluble? Load and lather a little faster? Lather just as awesome?
 
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