Numbers on soap bar quality

I have a general idea of what the numbers are on the soap calc website but I was wondering if someone could explain the interaction a bit more to me. For example, I have a formula with the following numbers:

Soap Bar Quality Range Your Recipe
Hardness 29 - 54 52
Cleansing 12 - 22 12
Conditioning 44 - 69 45
Bubbly 14 - 46 23
Creamy 16 - 48 50
Iodine 41 - 70 51
INS 136 - 165 156

When I use the bar, it feels wonderfully conditioning, although the conditioning number is at the lower end of the spectrum. I have also made bars with 70 on conditioning and they feel similar to the bar at 45. How does cleansing interact with conditioning to change the feel? I know cleansing deals with the mild/not so mild aspect but I can't really feel too much of a difference. My castile soap is super mild but dries the piss out of my skin.

What I am seeing here is that these numbers may not necessarily mean that much depending upon the oils used. This formula uses only coconut, castor, cocoa butter and hemp seed oil where the primary percentage is cocoa.

I can't find a link to it as I'm on the app, but if you search for 'soapcalc numbers' and look for posts by DeeAnna - she put together some amazing information on what they all mean.

Changed a lot of peoples' perceptions!

This is DeeAnna's explanation. It's worth book marking because there are a lot of reasons to go back and read it again. Again, this is NOT MY post. It's DEEANNA's!!!!

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When evaluating a soap recipe, you can look at the individual amounts of each fatty acid (myristic, lauric, stearic, palmitic, oleic, ricinoleic, linoleic, linolenic, etc) to determine the effect of each fatty acid on the soap ... or you can use the SoapCalc "numbers" to do much the same thing, only simpler. Problem is ... and I've said this elsewhere on SMF ... is that the names of the SoapCalc numbers are misleading. It is also important to remember that the fatty acid profile and the SoapCalc numbers do not account for the effect of superfat nor the effect of additives (sugar, milk, honey, sodium lactate, etc.)

So, okay, now let's look at the numbers for at a single fat -- let's choose your cocoa butter and assume we're going to make a soap from this fat. Cocoa butter has a fatty acid profile that looks something like this:

Lauric 0
Myristic 0
Palmitic 25-35% (average is about 30%)
Stearic 28-38% (average is about 33%)
Ricinoleic 0
Oleic 29-41% (average is about 36%)
Linoleic 2-7% (average is about 4%)
Linolenic 0

Lots of numbers, right? Let's look at how SoapCalc groups those numbers into fewer bits of useful information:

Hardness 61
Cleansing 0
Condition 38
Bubbly 0
Creamy 61

So now, okay, how does a person translate from the fatty acid profile to the Soapcalc numbers? Here's how:

Hardness: The hardness value is the sum of Lauric + Myristic + Palmitic + Stearic acids.

These are the saturated fatty acids. The Hardness number is a measure of the physical hardness-like-a-rock. It tells you how relatively easy it will be to unmold a particular soap after saponification. It does NOT necessarily tell you how long-lived the soap will be -- I'll get to that in a bit.

Hardness number from the fatty acid profile (above) = 0% + 0% + 30% + 33% = 63%.
Soapcalc Hardness = 61%.

Is the difference between 63% and 61% important? Nope, not too much. Keep in mind that any fatty acid profile for any particular fat is only an estimate. The SoapCalc folks calculated their Hardness number from slightly different data than we are using. Bottom line -- don't agonize over differences of a few percentage points.

Cleansing: The cleansing value is the sum of Lauric + Myristic acids.

It is a measure of how water soluble the soap is -- meaning it is a measure of how easily the soap dissolves in difficult situations such as hard water, cold water, or salt water. The Cleansing number does NOT tell you whether the soap will actually get your skin clean, which is the usual misinterpretation of the Cleansing number. A soap with a Cleansing value of zero will clean your skin; it is just not as water soluble in hard/cold/salty water as a soap with a high Cleansing value.

Cleansing number from the fatty acid profile = 0% + 0% = 0%
SoapCalc Cleansing = 0%

Conditioning: The conditioning value is the sum of Oleic + Ricinoleic + Linoleic + Linolenic acids.

These are the monounsaturated and polyunsaturated fatty acids. The conditioning value is, to the best of my understanding, a measure of the soap's ability to soften and soothe the skin. The "anti tight-and-dry" property, so to speak.

Conditioning number from the fatty acid profile = 0% + 36% + 4% + 0% = 40%
SoapCalc Conditioning = 38%

Bubbly: The Bubbly value is the sum of the Lauric + Myristic + Ricinoleic acids.

This is a measure of how much loose, fluffy lather is produced. A "bubbly" lather is produced quickly by a soap, but doesn't last long.

Remember that the first two fatty acids make a soap that is very soluble in water, so it makes sense that a soap that has a lot of these two fatty acids would make lots of lather, right?

Ricinoleic acid does not make soap that lathers well on its own, but combined with other fatty acids, it enhances the lather the other fatty acids produce. Does a low or zero Bubbly number mean the soap doesn't lather at all? Nope -- just that the soap might not have a lot of fluffy big bubbles.

Bubbly number from the fatty acid profile = 0% + 0% + 0% = 0%
SoapCalc Bubbly = 0%

Creamy: The Creamy value is the sum of the Palmitic + Stearic + Ricinoleic acids.

Palmitic and stearic are the fatty acids that produce lather that is fine textured (like whipped cream) and longer lived. Ricinoleic, as mentioned before, enhances lather, whether it be big, bubbly lather or dense, creamy lather.

Creamy number from the fatty acid profile = 30% + 33% = 63%
SoapCalc Creamy number = 61%

Long life: The longevity of a soap is the sum of the Palmitic + Stearic acids.

Palmitic and stearic acids create a soap that is relatively hard and relatively insoluble in water.

Long-lasting number from the fatty acid profile = 30% + 33% = 63%
SoapCalc Long-lasting number = ???

I said I'd get back to this issue. SoapCalc numbers do not directly measure longevity. Many people confuse the Hardness number as being a measure of how long lived the soap is, but that is not strictly correct. If you are working in SoapCalc, the fastest way to estimate the Long-lasting number is this:

SoapCalc Long-lasting number = Hardness number - Cleansing number

For cocoa butter, it's a no-brainer -- the Hardness number is the same as the Long-lasting number. For a Coconut Oil soap, the story is quite different:

Hardness = 79
Cleansing = 67
Long-lasting = 79 - 67 = 12

Compare that to 63 for cocoa butter. Bottom line -- a coconut oil soap will not last nearly as long as a cocoa butter soap, all other things being equal.


Okay, whew, I quit for now!

Thank you! I was looking for that yesterday! I knew it existed, just could not find it to save my life.

I was in a slight panic because I knew I had saved it and then I couldn't find it immediately. I thought I managed to delete it somehow and then I would never find it again! Thankfully I remembered I saved it to a document instead of the link to the post, as SMF lost all its info in the past. Don't want to lose this, for certain!

I have wondered something similar to the original poster if not the exact same thing. I've heard some people say in making a "conditioning" bar, they look for a high conditioning number as well as a low cleansing number. Plus when you take into account superfatting, I never know what's important to have in a bar of soap! From DeAnna's old post, I'm guessing that the cleansing number does not affect how conditioning the bar is -- that's only determined by the conditioning number and superfat, correct?

girlishcharm2004 said:

I have wondered something similar to the original poster if not the exact same thing. I've heard some people say in making a "conditioning" bar, they look for a high conditioning number as well as a low cleansing number. Plus when you take into account superfatting, I never know what's important to have in a bar of soap! From DeAnna's old post, I'm guessing that the cleansing number does not affect how conditioning the bar is -- that's only determined by the conditioning number and superfat, correct?

Click to expand...

Not exactly. Because the cleansing number indicates how much oil that soap can lift from your skin. If you strip too much oil from your skin, you are going to feel tight and dry regardless of the conditioning number and superfat. I just keep my coconut oil down to 20% or less to keep that dry feeling away. Then the superfat and conditioning numbers make the soap "more" conditioning. If you have oily skin, you may have different results, and may be able to tolerate a higher cleansing number. I have dry skin, especially in winter.

i usually don't care about these numbers. my current fave recipe is bad on paper, but if feels wonderful on my skin. so, yeah...

Yeah, I sort of backwards formulated my current favorite recipes based on how they felt to me, then I checked the numbers on soapcalc.net. I figured out the hard way that too much coconut oil/cleansing was not a happy feeling. Then I decreased that, and increased lard until I got something I loved. That is why I have so much grated bar soap for liquid soap, and why I know how to donate soap to the shelter, and how to put confetti soap in other soap, etc. Lots of trial and error, mostly with too much coconut oil.

"...in making a "conditioning" bar, they look for a high conditioning number as well as a low cleansing number..."

In doing more reading since I wrote the (apparently famous!) post that everyone is mentioning, I have started to learn more about some of the underlying issues about the soapcalc "cleansing" and "conditioning" properties of soap.

The short answer: For a mild bar, I think it is more important to have a fairly low or zero cleansing number (myristic and lauric acids plus the even-shorter chain fatty acids such as caprylic, caproic, butyric, etc.) than it is to have an unusually high conditioning number (oleic, linoleic, ricinoleic acids).

The longer answer: The "cleansing" fatty acids are irritants to the skin, because these short-chain fatty acids have the ability to remove the fats and proteins within the non-living protective surface layer of our skin (the stratum corneum). These fats and proteins help the stratum corneum remain smooth and elastic and maintain a good protective barrier over the underlying living tissues.

The skin responds to this irritation by feeling tight, itchy, and dry and eventually becoming red, irritated, swollen, and rough. This damage is additive, meaning the more we wash, the more irritation that is caused. Low humidity in winter or living in an arid climate makes this damage even more likely.

The longer chain fatty acids (stearic, palmitic, oleic, linoleic, linolenic, etc.) are not as able to cause this type of damage, so they're called the "conditioning" fatty acids. The name is misleading, in my opinion, because soap really cannot condition the skin. Conditioning is the blanket property of adding humectancy (water) to the stratum corneum, providing occlusion (barrier to abrasion or water evaporation), and adding emollience (replacing lost fats), as well as smoothing and soothing the skin.

Some of the additives in a soap can add some conditioning, but soap itself cannot. Soap cleans. Period. Maybe the "conditioning" fatty acids should have been called "non-stripping" and the myristic and lauric acids should have been called the "stripping" fatty acids.

Some people's skin is more sensitive to this type of damage than others. That is most likely why some soapers can't see all the fuss about using, say, 30% coconut oil in a recipe while others shudder at the thought of anything over 10%. Or why some soapers formulate a wintertime soap that is less cleansing than their summertime soap.

Why does a soap with certain conditioning numbers and cleansing numbers feel different than another soap with the exact same numbers, all other things being equal? I think you then have to look at the actual fatty acid analyses of the two recipes. A soap with, say, 20% oleic and 10% linoleic and a second soap with 10% oleic and 20% linoleic will have the exact same score for "conditioning". Might they feel different on the skin? Certainly!

There's an even longer answer to this issue of soap made with cleansing vs. conditioning fatty acids that is based on stuff like "critical micelle concentration" and water solubility. But that's a story for another day.

*Lots of hugs to DeeAnna*

AMAZING information. DeeAnna, please write a book so I can buy it. At the least DeeAnna, you should consider writing a very detailed blog about everything you just said. I was completely misreading those numbers this whole time and now I understand why I wasn't making sense out of it. I guess the only way to really know what the heck you are doing is to ignore the basic numbers and start reading the percentages of fatty acids.

DeeAnna said:

Some of the additives in a soap can add some conditioning, but soap itself cannot. Soap cleans. Period. Maybe the "conditioning" fatty acids should have been called "non-stripping" and the myristic and lauric acids should have been called the "stripping" fatty acids.

Click to expand...

Ah, I have always thought of them as stripping and non-stripping -- only because I was under the impression that "cleansing" meant the amount of oils that were lifted from the skin, thus taking away all the dirt and debris trapped in that layer (the stratum corneum). Then after reading your previous (famous) post I kept reminding myself that it's not "cleansing", it's how fast the bar dissolves in water. My head is spinning now.

My other question would be then, is it more important to have a high superfat and other additives, or a high conditioning number (both in combination with a low cleansing number)? It sounds like the former.

Also, the barrier that keeps skin smooth/elastic and keeps water from evaporating, is that merely oil between all the skin cells (is it the basal skin cells?)? Or does the oil ever actually penetrate the cells?

Lastly, this is all so fascinating, where do you get your reading material from!?? Ha.

"...it's not "cleansing", it's how fast the bar dissolves in water...."

Actually this water solubility is part of the reason why a "cleansing" soap can be harsh to the skin. The higher the water solubility, the more soap that dissolves off the bar, thus there is more soap to strip oils and proteins off the skin surface and potentially cause irritation to the skin.

There's another rather obscure factor that contributes to the harshness/cleansing/solubility thing, and that's the "critical micelle concentration" (CMC) of the different types of soaps. A high CMC is related to the unusual ability of soaps made from short-chain fatty acids to remove fats and proteins from the stratum corneum. The longer chain soaps with a low CMC apparently do not have this ability. (I'm still learning about this.) The essential point is that the short chain fatty acids -- myristic and lauric acids being the most common of these -- make soap that is highly soluble in water AND highly cleansing.

"... is it more important to have a high superfat and other additives, or a high conditioning number (both in combination with a low cleansing number)..."

I'm an equal-opportunity skeptic on all of this. I don't believe in high superfat; I typically use the soapcalc equivalent of about 3% superfat. I know many soapers strongly feel otherwise. I also think additives are not a panacea, although it's certainly fun to play around with them.

It's my goal to formulate a soap with low cleansing (myristic, lauric), moderate conditioning (oleic, linoleic), and relatively low solubility (palmitic and stearic). When I stick with that approach with 3% superfat and minimal if any additives, I get a mild soap that is not drying to the skin, lasts a long time, and has a decent lather. So I can't exactly say either of the strategies you list is a requirement for a mild soap.

"... the barrier that keeps skin smooth/elastic and keeps water from evaporating, is that merely oil between all the skin cells (is it the basal skin cells?)? Or does the oil ever actually penetrate the cells?..."

I'm not a skin expert, but according to my beginner understanding, the barrier I think you're talking about is the stratum corneum -- the dead but protective surface layer of skin. It is made up of lipids (fats), protein, and water-based liquids. I doubt fats can actually penetrate into the living cells in the skin layers below the stratum corneum. Fats are big molecules. They can certainly bind to the surface of cells, but I'd say it's unlikely that fats can actually penetrate inside the cells.

"...where do you get your reading material from..."

Dermatological research papers, modern books on detergent technology, old soap making manuals from the 1800s and early 1900s. Stuff like that. It can be pretty heavy going at times, but I just "get my girl geek on" and plug away.

DeeAnna said:

I'm an equal-opportunity skeptic on all of this. I don't believe in high superfat; I typically use the soapcalc equivalent of about 3% superfat. I know many soapers strongly feel otherwise. I also think additives are not a panacea, although it's certainly fun to play around with them.

It's my goal to formulate a soap with low cleansing (myristic, lauric), moderate conditioning (oleic, linoleic), and relatively low solubility (palmitic and stearic). When I stick with that approach with 3% superfat and minimal if any additives, I get a mild soap that is not drying to the skin, lasts a long time, and has a decent lather. So I can't exactly say either of the strategies you list is a requirement for a mild soap.

Click to expand...

Thank-goodness! I was afraid you were going to recommend superfatting! On Soapcalc, I just leave it at the default of 5%. I heard people talking about superfatting at 8-20%, so I gave 10% a try and hated it.

I don't have particularly sensitive skin, but I would like to make soap for others I know who have eczema. I feel at a loss of how to read the numbers to produce a worth while bar. I have made 4 different batches of soap, but maybe they aren't different enough because I can't tell a difference between them. Ha.

DeeAnna said:

"...where do you get your reading material from..."

Dermatological research papers, modern books on detergent technology, old soap making manuals from the 1800s and early 1900s. Stuff like that. It can be pretty heavy going at times, but I just "get my girl geek on" and plug away.

Click to expand...

One of the things you had mentioned, I recognized from a soap book I downloaded on my Kindle (late 1800/early 1900)! Some of that old literature is a difficult read. Good for you to plug away and even more impressive to understand it!

I don't have good suggestions about a soap for eczema sufferers, but there are a lot of threads on SMF about this topic and maybe others who do have a clue will chime in here.

".. I have made 4 different batches of soap, but maybe they aren't different enough because I can't tell a difference between them. Ha. ..."

Ha back atcha! I'm not surprised to hear that especially since you (like me) have pretty much normal skin vs. sensitive or damaged skin. I can perceive some differences between some of my soaps, but I probably couldn't find the differences between all (or even many) of my soaps. I think that is especially true when I'm looking at the properties that specifically affect skin feel (cleansing, conditioning).

What I find as I use a bar from any one particular recipe (pick any one at random, don't look at the recipe, ignore what it looks like), I find myself going "hmmm, well it's okaaaay, it's soap, it gets me clean" versus "wowser, I LIKE this one -- it makes me happy to use it". Then I start asking WHY I like the "wowser"soap, and it usually comes down to the lather quality.

Most of the soaps I make don't create a big variation in how my skin feels -- my skin feels nice when I bathe and after I towel off, regardless of the recipe. Maybe that's a good thing. Perhaps my skin is telling me my recipes are all fine, regardless of trying this blend of fats in one batch vs. that blend of fats in another! Or maybe my more-or-less normal skin is just not terribly "princess and the pea" sensitive to the differences.