Soap Chemistry and a Stupid Question

[synapticmisfires]

So I just finished writing in a contest thread about how my dad using Ivory bath soap to shave (rubbing it on, shaving as he applies). Well more as a thought experiment than anything, I've been wondering what kind of results Ivory would get if were to actually be treated as a shave soap: Brush, bowl, soaking, the works.

Admittedly this is a stupid question, the consensus seems to be that you don't get good, stable, slick lather with bath/face soap. I just want to know why. The ingredients of Ivory are actually pretty reasonable-looking at first blush:

sodium tallowate and/or sodium palmate, water, sodium cocoate or sodium palm kernelate, glycerin, sodium chloride, fragrance, one or more of the following: coconut acid, palm kernel acid, tallow acid or palm acid and tetrasodium EDTA.

(via wikipedia)

Williams is kind of the standard for dirt-cheap tallow soap, so for comparison:

Sodium Tallowate, Potassium Stearate, Sodium Cocoate, Water, Glycerin, Tetrasodium Etidronate, Pentasodium Pentetate, Fragrance, Titanium Dioxide

Both have sodium salts of tallow and coconut oil, both have water softeners, both have glycerin, and seemingly in similar proportions. I did some google-fu, and found a clue here (a highly informative read, I recommend it). While the OP there said something about palm oil and tallow being very effective, he also seems to believe that potassium salts produce more stable lather. Ivory does lack the potassium stearate of Williams, but could one ingredient really make that difference? Is Williams just such a poor, sodium heavy shave already that the subtraction of this one ingredient leaves it completely useless? This seems implausible because Ivory is kind of soft to the touch and seemingly highly water soluble, the two features the OP cites as being benefits of potassium.

Essentially, I'm wondering if any of you have experience using bath soaps for shaving, or if you can tell me why potassium matters so much. I'd also love to hear your own thoughts on what the key ingredients and attributes of a good soap are. Finally, maybe some of you will find that link as informative as I did in clarifying our understanding of the products we use so much.

[soapbox]

While the OP there said something about palm oil and tallow being very effective, he also seems to believe that potassium salts produce more stable lather. Ivory does lack the potassium stearate of Williams, but could one ingredient really make that difference? Is Williams just such a poor, sodium heavy shave already that the subtraction of this one ingredient leaves it completely useless? This seems implausible because Ivory is kind of soft to the touch and seemingly highly water soluble, the two features the OP cites as being benefits of potassium.

Essentially, I'm wondering if any of you have experience using bath soaps for shaving, or if you can tell me why potassium matters so much. I'd also love to hear your own thoughts on what the key ingredients and attributes of a good soap are. Finally, maybe some of you will find that link as informative as I did in clarifying our understanding of the products we use so much.

That's a lot of questions!

I'll work backwards.

Yes, I use bath soap to shave my head, and have used it to shave my face in the past. Yes, in general bath soaps have trouble with lather stability (it's not a primary requirement for bath soaps so this issue isn't surprising). I also think that my good shaving experience with a bath soap is directly related to the glycerin in the soap and the soap itself -- that is, not every soap will be good for slick lather, even if the shaving lather isn't stable.

Potassium hydroxide produces a mushy, pasty soap if you don't use any sodium hydroxide. Potassium soap is the basis for liquid soaps (and note this doesn't include any detergents like dishwashing liquid or laundry detergent) because it's more soluble in water than sodium soap is. If you grind up sodium soap or heat sodium soap until it melts, you get "apricot preserves", as my father describes it. So, water solubility might have something to do with lather stability.

Second, the mix of oils in the saponification process may have as much to do with lather performance as any one oil's presence or absence. You'll find a lot of people who claim that tallow soap is superior because it includes tallow. Maybe so. Palm oil is chemically and statistically very similar to tallow, and maybe if I asked dad to make an all-vegetable shave soap, he'd substitute palm oil for tallow. But you can get lost in the infinite variety of saponifiable oils and waxes. And that's not even mentioning non-saponifiable products that some folks include in their soap.

As for my thoughts on key ingredients and properties of a good shave soap, it's very subjective beyond a very basic description, so I won't try to set up a perfect standard. There are a lot of good shave soaps out there, and there's a huge variety in the composition and performance of those lather-producing products. Part of the joy of wet shaving is trying a new soap and comparing it to others you've tried.

[Mama Bear]

you can shave with just about anything that gives you something slick and cushiony. I always used body soaps to shave my legs.. but then again.. the hair on my legs are finer than frog leg's hair. Trust me, I have gotten up close and personal to verify this. The silk on a woman's legs is not the same as the wire on a man's beard however... using an analogy.. a scythe once cut down a field of weeds just fine... however.. these days we judge each other... and ourselves.. by the way we take care of ourselves. Also.. if we do it right.. we look younger and better. Dove is fine soap... or it was once. Granma's homemade soap was great once apon a time.. but the times have changed and knowledge has changed and we have applied that knowledge to creating better products.. and thank god for that. But remember.. what is the holy grail to one person.. doesn't chemically react for another person in the same way.. the plethora of products out there are there because they DO work for some people.. everyone says coconut oil is drying.. it's not to me. I adore it! A lot of folks really like clay in their soap for slip.. I don't.. there are better ways to me. But this is the information age.. and B&B to me is one of the best things to come out of the internet.. just remember.. one persons treasure is another man's garbage. you have to discover what works for you.. and in doing that you will be well rewarded.

[Mama Bear]

So I just finished writing in a contest thread about how my dad using Ivory bath soap to shave (rubbing it on, shaving as he applies). Well more as a thought experiment than anything, I've been wondering what kind of results Ivory would get if were to actually be treated as a shave soap: Brush, bowl, soaking, the works.

Admittedly this is a stupid question, the consensus seems to be that you don't get good, stable, slick lather with bath/face soap. I just want to know why. The ingredients of Ivory are actually pretty reasonable-looking at first blush:
(via wikipedia)

Williams is kind of the standard for dirt-cheap tallow soap, so for comparison:


Both have sodium salts of tallow and coconut oil, both have water softeners, both have glycerin, and seemingly in similar proportions. I did some google-fu, and found a clue here (a highly informative read, I recommend it). While the OP there said something about palm oil and tallow being very effective, he also seems to believe that potassium salts produce more stable lather. Ivory does lack the potassium stearate of Williams, but could one ingredient really make that difference? Is Williams just such a poor, sodium heavy shave already that the subtraction of this one ingredient leaves it completely useless? This seems implausible because Ivory is kind of soft to the touch and seemingly highly water soluble, the two features the OP cites as being benefits of potassium.
.

I doubt that one ingredient will make a huge difference. with soap, it is more about the blend.. the recipe so to speak.. how much of what kind of lye.. with how much of what fatty acid and in what proportion. Each product is different.. and some have been designed by chemical engineers with more letters after their names than I have in my whole name.. and some by folks that like to make things at home and are crafty and curious. Who is to say which is better. In these days there is a strong change back towards home crafted soaps.. as is there is back to wet shaving

But i am gona say this.. if you like Ivory for a shaving soap.. you will be amazed at what has happened since your fathers day..

Welcome to B&B, let the learning begin.. ;-)

Edit again.. with apologies.. bath soaps are best created to wash away the dirt and bacteria.. which is exactly what soap does. It takes it off your skin and it goes down the drain. Shaving soaps are another animal.. they aren't meant for cleaning.. they are meant for providing a base that will form a protective area between your face and a sharp blade. For this bath lather isn't good enough. It is lather that makes a shaving soap.. and for good reason.. it gives you cushion.. protective layer.. and it gives you slip.. nothing worse than drag.. drag causes nicks. In addition.. the face is a whole lot more sensitive then the body.. and while many of use use body soaps all over.. leaving a body soap lather on your face can cause reactions especially with someone with sensitive skin. chuck norris has sensitive skin.. ok.. seriously.. it's not about being manly, it is about knowing yourself, your beard and your skin.. and bath soaps aren't tailored to give a shave with those factors..

ok.. off my soap box.. sorry all

[Mama Bear]

Potassium hydroxide produces a mushy, pasty soap if you don't use any sodium hydroxide. Potassium soap is the basis for liquid soaps (and note this doesn't include any detergents like dishwashing liquid or laundry detergent) because it's more soluble in water than sodium soap is. If you grind up sodium soap or heat sodium soap until it melts, you get "apricot preserves", as my father describes it. So, water solubility might have something to do with lather stability..

I like lumps in my mashed potatos.. and even in my gravy.. just not in my soap.. lol

Jesse.. we need your dad more and more around here.. I am so glad we have you! Bear Hugs!

[LinuxMintyFresh]

I tried a high-glycerine bath soap the other week just to check it out, and it didn't lather very well, but if I were camping or something it would work just fine. I guess it sort of depends on what you need. I'll stick with my MWF and my Mama Bear's Cannabis (still wishing it was "Dried Bud" ) at home, though.

[cymric]

Admittedly this is a stupid question, the consensus seems to be that you don't get good, stable, slick lather with bath/face soap. I just want to know why.

It helps to understand the entire thing by looking at a soap molecule first. It rather resembles a sewing pin. The knob (or 'end') carries a charge, in the shaving business nearly always a negative one, and the actual pin itself is the fatty acid molecule. The pins come in various sizes ranging from short (capric and lauric acid) to medium (myristic and palmitic acid) to long (stearic and arachidic acid). However, in real life those 'tails' as they are more commonly referred to are not rigid, they are flexible. Sometimes it's a mixture of flexible and rigid parts.

Now what happens during the lather building is that these molecules arrange themselves on the water /air bubble interface in a very specific pattern. Tails are hydrophobic and prefer not to be in water if they can can avoid it; ends are hydrophyllic and behave in the opposite fashion. The charged end is surrounded by water molecules, and the tails are sticking out into the air bubble. You could say that it rather resembles a little fur. The main body of water cannot see there is a surface anymore which it usually resents, and so happily allows air bubbles to be taken up in its bulk. Hey presto: lather. Now for lather in order to be stable, the 'fur' must hold itself together against various forces. That is a bit of a problem as the charged ends all repel one another. The ends, however, attract each other, and like to tangle themselves all up. But this requires a certain minimum length: if the tail ends are too short, the distance imposed on them by the charged ends is too big for them to overcome, resulting in weak attraction and thus a weak 'fur'. The lather cannot sustain itself and breaks apart easily. That's what happens with pure coconut oil-based soaps: you get bubbles, but they tend to be big and break apart easily. In shaving soaps, specific molecules with longer tails were added so the 'fur' is very stable: the longer the tail, the firmer the foam. Stearic acid is more or less the staple ingredient for this job.

But... as you increase the length of the tail, the solubility of that molecule goes down significantly, making it harder for a good and rich lather to form in the first place. That's where the second bag of tricks comes in: replacing sodium with potassium (which increases solubility like nothing else), but also replacing a small portion of completely flexible tails with semi-flexible ones. Because of those rigid parts, the tails don't align themselves very comfortably in a solid (read: the soap), and thus have less trouble dissolving. But you can't have your cake and eat it: less trouble dissolving also means more trouble holding together in the lather. You can improve that by adding smaller flexible tails so that a semi-flexible one is supported from 'underneath' by a short tail, and 'on top' by a large one. Look for coconut or palm kernel derivatives.

But if you have too much potassium in the soap... it becomes more or less a paste which may be hard to handle. Think the soft Italian shaving soaps Cella, P.160 and Valobra here. Hard soaps can be cut, mixed, and milled very easily; the soft varieties require more effort as they stick to equipment.

And then you also want slickness, yaddayaddayadda. In other words: it's a tricky business to get right. But now you know why bath soaps usually don't make good stable lathers.

[dog]

admittedly, I don't think I could get a worse lather out of ivory than I did out of Williams. There are quite a few people who have a problem lathering Williams.

The point I'm trying to make, I suppose, is that maybe Williams shouldn't be your baseline :)

[soapbox]

I like lumps in my mashed potatos.. and even in my gravy.. just not in my soap.. lol

Jesse.. we need your dad more and more around here.. I am so glad we have you! Bear Hugs!

aw shucks ma'am. Thank you.

(Though, Cymric is a real chemist, and I'm thankful to have him around too!)

[Jim]

How can you not love this place?

[kingfisher]

So, what cymric is saying is that yes, the potassium stearate could, in fact, make that much difference.

[WhosYerBob]

Excellent thread - I keep learning more and more everyday!

[Boba Fett]

Science!!

[mliguori]

Where else in the world could I read about intelligent discussion of the chemical properties of bath vs shaving soaps? This place is great.

[Beast]

So.. how is the Cannabis soap/scent?
Does it stick around for a while?

I tried a high-glycerine bath soap the other week just to check it out, and it didn't lather very well, but if I were camping or something it would work just fine. I guess it sort of depends on what you need. I'll stick with my MWF and my Mama Bear's Cannabis (still wishing it was "Dried Bud" ) at home, though.

[gollum83]

So, what cymric is saying is that yes, the potassium stearate could, in fact, make that much difference.

No, what he is saying is that you can affect the properties of a soap in many different ways. Making the soap with potassium hydroxide rather than sodium hydroxide can certainly affect solubility and the stability of the lather, among other things, but that alone hardly determines the properties of the soap. It depends a great deal on oils used in saponification as well. Remember, oil olive, for instance, makes pretty lousy shaving soap regardless of the type of hydroxide used.

To further illustrate this, let's look at one of those soft soaps. The ingredients in Cella are as listed:

Palm oil, tallow, stearic acid, potassium hydroxide, sodium hydroxide, water, potassium carbonate, perfume

As you can clearly see, there's more potassium hydroxide used in Cella than sodium hydroxide. So potassium based soap molecules, like potassium stearate and potassium palmitate, predominate over sodium based ones, like sodium stearate and potassium palmitate. However, that hardly affects the lather to any reasonable extent, as Cella provides great lather for a great shave. At the same time it's worth noting that Cella has a variety of different types of soap molecules all working together, yet this is true of any soap. Even if you're just using sodium hydroxide, for example, your fatty acids are quite typically a mixture of various molecules. Tallow alone contains a number of saturated, monounsaturated and polyunsaturated fatty acids including palmitic, stearic, myristic, oleic, palmitoleic, and linoleic acid.

[jkenton]

My grandpa used to shave with hand soap (I recall Dial, but there was also Ivory around).

I think the situation is like this: If it works for you, great. I'm not as good at shaving with bar soap as my grandpa was. When I have shaved with regular soap, I have paid dearly (mostly in skin dryness and tightness).

Isn't Dove soap 1/4 moisturizing cream or some such nonsense?

[henkverhaar]

So, what cymric is saying is that yes, the potassium stearate could, in fact, make that much difference.

Correct. It will.

[henkverhaar]

No, what he is saying is that you can affect the properties of a soap in many different ways. Making the soap with potassium hydroxide rather than sodium hydroxide can certainly affect solubility and the stability of the lather, among other things, but that alone hardly determines the properties of the soap.

Actually, it does. THere are a few things that define a (fatty acid salts based) shaving soap, and it being a potassium/sodium soap with a potassium to sodium ratio of 6:4 or better is the single most important factor.

Of course there are other factors that influence the performance, but without potassium -- no shaving soap.

Henk

[gollum83]

Actually, it does. THere are a few things that define a (fatty acid salts based) shaving soap, and it being a potassium/sodium soap with a potassium to sodium ratio of 6:4 or better is the single most important factor.

Of course there are other factors that influence the performance, but without potassium -- no shaving soap.

Henk

I'm not disagreeing with you, I was try to say that it's hardy the only thing that will determine it.

Next time I'll stay the hell out of these darn discussions.