Cure time...

[beckster51]

DeeAnna, The information that you provide to the forum is absolutely priceless! I am a science geek, so I read all your posts with bated breath. Thank you so much for giving us this valuable and fascinating information. I truly appreciate it.

 

[earlene]

Well, color me fascinated. I had never heard of adding KOH to increase lather over a short period of time. Since it softens soap, I would think that I might have to do a water discount, especially since I use some "soft" oils in my soap. Or does this small amount of KOH have little to no effect on soap hardness? I plan to do this in my next batch, so I hope someone answers this one before I do that in the next few days. I am finally getting in the routine of making soap well ahead of time after accepting that there is no substitute for time in curing. I ran across an old bar the other day, and it was fabulous. Hard with great stable lather, although the fragrance had faded quite a bit.

I haven't noticed if anyone answered your question above. Maybe it was answered & I forgot because I have kept coming back to this thread and only re-reading some of it and not responses every time.

I have made only a few batches of 95% NaOH with 5% KOH bar soap, so take my response with a grain of salt. No, it doesn't in such a low percentage. In a higher percentage it does, but that is also dependent on your recipe. As you can surmise, soaps with a higher percentage of hard oils would be less affected, whereas soaps with a higher percentage of soft oils would be more affected.

I tend to use more soft oils in most of my recipes and noticed a significant difference when I tried a 10% KOH/90% NaOH in softness of the resulting soap. I expect a long cure will solve the problem eventually, but haven't looked back at those particular soaps in a while, so don't yet know. I can only hope.

~ ~ ~ ~ ~

DeeAnna, I have another question or two for you. Please bear with me because my college chemistry days are long ago in my past, and although I thoroughly enjoyed and was fascinated by my courses, some of what I learned is now a hazy memory.

You mentioned a couple of phases that didn't quite ring a bell for me, so I did a little searching online and in one book. Still I find myself not clear on these phases. Kevin Dunn has referred to the water phase at some point in his lectures and I found at least one mention in his book where he defines the liquid-crystalline phase as gel phase (Neat Soap, page 391 Scientific Soapmaking). Other than that, I had a hard time finding something to help me really grasp these terms as they relate to curing soap. Probably all I did by searching for answers is to become more confused.

So what is the liquid phase? When you talk about it, you are talking about bar soap, that is solid bar soap already in the curing process. So I'm not grasping the meaning of liquid phase in this context. Please understand I am not trying to be difficult, I am trying to understand the concept of what liquid phase means here. I don't think it means gel phase as I understand liquid-crystalline phase to mean since we are talking about soap while it cures.

And what is the water phase (in curing soap)? Which comes first, or do they both exist simultaneously in different parts of the same bar of soap during cure? I sort of think the latter is the case, but am unsure.

Earlene

 

[Steve85569]

Fascinating post and awesome answers!

I *think* I just learned a bunch....

 

[DeeAnna]

The liquid phase is the fluid within and between the soap crystals in bar soap. You're talking like it only exists at certain times, but it is always there in soap regardless of its age. As water evaporates, the liquid phase becomes smaller in volume, that is true. But it never disappears.

***

The most common usage of the word "gel" for us handcrafted soap makers is what happens during CP or HP saponification when soap gets warm enough to turn from a solid form into a softer paste something more like Jello or peanut butter. What Dunn calls "neat soap" as opposed to "curd soap." This is the response of soap to an increase in temperature at a relatively constant water content.

Although I think most soapers view this as the only "real" way that soap gels, this is is not really true.

Soap can also change into a gel in response to changes in water content at a relatively constant temperature. Soap can become a gel even at room temperature, if sufficient water is added. Some soaps gel easier than others, however. An example of this is when oleic bar soap absorbs water to form a clear jello-like substance (aka castile slime). Or when someone tries to make "liquid soap" by grating bar (NaOH) soap and adding water. The resulting runny liquid can eventually restructure itself into a Jello-like gel. This is also "gel" just like the gel that results from higher temps.

***

You can think of bar soap as a really complex material with extra physical phases in addition to the usual solid and liquid (and gas) phases we normally expect to find - water being an example of something with uncomplicated phase changes.

Bar soap is solid when it is sufficiently cool and has not too much liquid in it so the soap crystals are fixed more or less in place. The point at which soap is a solid will vary depending on the fatty acids in the recipe.

Bar soap turns into a gel form when it is warm enough and/or contains enough water so the crystals are able to "unstick" enough so they can slide around each other. There are various forms of liquid crystals, so the flowable nature of a soap in gel can vary. Soap makers break Dunn's "neat soap" into several sub groups depending on the type of gel formed by the soap.

Bar soap becomes what's called an isotopic solution when sufficient water is added and/or sufficient heat is added so the soap in solid or gel form can break down into individual molecules. An isotropic solution is very fluid (runny). This is what happens to soap in your bath water.

 

[Spice]

No apology necessary, Spice. I didn't think you were talking to me specifically -- more talking in general about your reactions and feelings. We're good!

Thank God!

 

[earlene]

The liquid phase is the fluid within and between the soap crystals in bar soap. You're talking like it only exists at certain times, but it is always there in soap regardless of its age. As water evaporates, the liquid phase becomes smaller in volume, that is true. But it never disappears.

***

The most common usage of the word "gel" for us handcrafted soap makers is what happens during CP or HP saponification when soap gets warm enough to turn from a solid form into a softer paste something more like Jello or peanut butter. What Dunn calls "neat soap" as opposed to "curd soap." This is the response of soap to an increase in temperature at a relatively constant water content.

Although I think most soapers view this as the only "real" way that soap gels, this is is not really true.

Soap can also change into a gel in response to changes in water content at a relatively constant temperature. Soap can become a gel even at room temperature, if sufficient water is added. Some soaps gel easier than others, however. An example of this is when oleic bar soap absorbs water to form a clear jello-like substance (aka castile slime). Or when someone tries to make "liquid soap" by grating bar (NaOH) soap and adding water. The resulting runny liquid can eventually restructure itself into a Jello-like gel. This is also "gel" just like the gel that results from higher temps.

***

You can think of bar soap as a really complex material with extra physical phases in addition to the usual solid and liquid (and gas) phases we normally expect to find - water being an example of something with uncomplicated phase changes.

Bar soap is solid when it is sufficiently cool and has not too much liquid in it so the soap crystals are fixed more or less in place. The point at which soap is a solid will vary depending on the fatty acids in the recipe.

Bar soap turns into a gel form when it is warm enough and/or contains enough water so the crystals are able to "unstick" enough so they can slide around each other. There are various forms of liquid crystals, so the flowable nature of a soap in gel can vary. Soap makers break Dunn's "neat soap" into several sub groups depending on the type of gel formed by the soap.

Bar soap becomes what's called an isotopic solution (a solution runny as water) when sufficient water is added and/or sufficient heat is added so the crystals break down into individual molecules. This is what happens to soap in your bath water.

So when you were talking about the water phase previously (post #53 & #54), it was in reference to the liquid-solid-gas properties of the water phase? That's what I thought at first, then doubted my assumption. Or did you mean it as when we add water to the bar of soap to make it liquid again? Now I am just getting confused again. (So sorry to be hard to educate. I've always had to ask a lot of clarifying questions when I don't grasp a concept.)

You are right, the word phase means something different to the layperson than it does to the scientist, I think. I could be wrong, of course, but I think generally 'phase' in the layperson's mind is more like a time-related event. Example: The kid is going through a phase (time limited and not constant.)

I am sure that is part of what is causing my confusion. My scientific training is quite limited and I don't really recall much about simultaneous or co-existing (not really sure what the right word here would be) phases.

You are right, I do know that there is liquid or water in soap bar soap at all times, but never thought of it as a phase, probably because of my non-scientific understanding of the word/concept of phase.

Thank you for taking the time to expand on this issue.

Earlene

 

[DeeAnna]

I've corrected my earlier posts to only use "liquid phase" throughout. In two places I had carelessly written "water phase" when I should have written "liquid phase."

***

Lots of apparently solid things contain liquid, and soap happens to be one of them. When talking about bar soap, a loaf of bread, a hard boiled egg, or many other things of this nature, you can discuss the dry part of the material -- its solid phase -- or you can talk about wet part -- in other words, its liquid phase.

What I mean by "liquid phase" is the liquid found inside an apparently solid, dry bar of soap -- this liquid originates from when the soap was made. This would be any liquid used to make the soap such as water, beer, fluid milk, etc; the glycerin made during saponification; any dissolved salts or sugars from the recipe; etc. "Liquid phase" does not mean the water added when you use the bar of soap to wash.

***

I get the feeling, Earlene, that you're confusing my talk of the "liquid phase" in solid bar soap with Dunn's discussion about "neat" soap. You can't take what he's talking about and apply it to what I'm talking about. To relate this back to a simpler example, Dunn is talking about "water" and I am talking about "ice". The same chemical but in two different physical forms.

You brought up the term "neat" soap but didn't seem to understand what it really meant, so I tried to explain what "neat" soap is. Here are examples --

---- Neat soap is what you get when you soak a bar of olive oil soap in water -- the Jello-like goop or slime on the bar is "neat" soap.

---- Neat soap is what HP soap makers see when their soap looks like "vaseline" during the cook.

---- The thick paste that liquid soapers make as well as the diluted soap they make from that paste are both examples of "neat" soap.

Again, "neat" soap can also be called soap in "gel" phase or it can be called a liquid crystal. It can even be called a colloid. It all means the same thing. What "neat" soap is NOT is a solid soap like a bar of soap. My earlier posts talking about curing bar soap (Posts #51-55) are only talking about solid soap.

***

I don't know if I'm answering your questions, Earlene. I'm not sure what I can say to make things clearer. Soap is complicated stuff.

 

[beckster51]

Earlene, thanks so much for your reply. I found it very helpful and appreciate your courtesy!

 

[DianaMoon]

I'd like to add my voice to the chorus of thank you's to DeAnna!

 

[DeeAnna]

... So with that in mind, how does the KOH increase lather/decrease snottiness early in the cure?

It's been almost a year, BG, but I still haven't forgotten your question. Finally, in a fit of inspiration (or insanity) today, here is my answer --

A basic soap molecule looks something like a Tootsie Roll Pop, especially if you look at soap molecules made from straight chain fatty acids (palmitic, lauric, stearic, myristic) rather than fatty acids with bends (oleic, linoleic, linolenic, ricinoleic).

The long stem of the Pop is the fatty acid and the candy sphere stuck onto one end of the stem is a sodium (Na) ion or a potassium (K) ion depending on whether you used NaOH or KOH to make the soap.

Let me talk a bit more about the Sodium version first --

If you stick Tootsie Roll Pops into a styrofoam ball to make a candy centerpiece, the stems point inward to the center. The candy ends face outward touch each other. This is roughly how soap crystals are constructed in a bar of soap -- they pack together so the sodium ions face out toward the watery liquid phase, and the fatty acids point inward toward any superfat or other fat-soluble materials.

Sodium ions are a bit fatter around than their fatty acid stem, but this tidy packing arrangement works pretty well for sodium soap molecules. They are quite happy to form solid-ish balls and plates and hotdogs and stay that way. As we use a bar of soap for bathing, these sodium soap molecules will only reluctantly let go of their neighbors to become fully liquid.

For soap molecules made with straight fatty acids, the jump from solid to liquid is fairly abrupt -- one moment there are soap crystals, and the next there is a watery, sudsy soap solution. To use another analogy, these soap molecules act a bit like bricks in a wall -- the bricks remain firmly together as long as the mortar lasts, but once the mortar fails, the bricks fall easily.

Source: http://danareneestyle.blogspot.com/2013/04/pinspired-candy-topiaries.html

If you could see sodium soap molecules made with lots of oleic acid or other bendy fatty acids, you would see a similar story, although the resulting "candy centerpiece" in a high-oleic soap is not nearly as tidy. The bends in oleic acid and similar fatty acids prevent the soap molecules from packing together as tidily and tightly as their straight chain cousins.

The solid-ish crystals in a high-oleic soap are not as "waterproof" as crystals in a low-oleic soap. When you wash with bar of high-oleic soap, the water penetrates quickly into the high-oleic crystals, and that causes the crystals to deform and slide past each other. The crystals haven't quite given up being crystals, but they are not able to stay rigidly fixed in place.

This liquid crystal stage is when we see that ropy oleic gel (or snot) we all love to hate. As more and more water is mixed into the soap, the liquid crystals (aka the oleic gel) gradually break down into a watery, sudsy soap solution.

A high-oleic soap is more like a bowl of spaghetti with alfredo sauce. The strands of spaghetti are a tangled ball stuck together with the sauce. When you pick up a bite with a fork, the strands gradually untwine and pull apart.

Potassium soap molecules have the same general shapes as sodium soap molecules, except for one key difference -- the diameter of a potassium ion (the candy at the end of the fatty acid stick) is quite a bit larger than the diameter of a sodium ion, because the electrons of a Potassium ion are not held as tightly by the nucleus (the center) of the ion. Potassium is more like a big, soft marshmallow, and Sodium is more like hard candy.

The bulky Potassium ion prevents the soap molecules from packing as tightly and neatly together. This is true regardless of the fatty acids the Potassium ions are attached to. This interference allows water to penetrate more easily into the crystalline structure, so the soap molecules can more easily dissolve into the wash water.

To go back to my analogies, potassium weakens the mortar of the brick wall (soap molecules made with straight fatty acids) and it makes the pasta (soap molecules with bent fatty acids) more slippery and slithery.

So in summary --

By adding a bit of KOH to a high lard (or palm or tallow) recipe, the fairly insoluble soap molecules created from stearic and palmitic acids will become more soluble in water. You'll get more lather quicker and with less work.

Adding a bit of KOH to a high-oleic soap will make the oleic gel not quite as strong. The gel will "snot" less and dissolve better into the wash water.

edited to clarify my explanation

 

[Spice]

DeeAnna, your intelligence fascinates me!

 

[dibbles]

Wow DeeAnna, great explanation. And with a visual aid too!

 

[Meena]

Okay, here's my answer to Newbie's question in Post 36. In a nutshell, she asked, "...is the organization of the molecules dependent on the process of evaporation?..."

My answer is long and more complicated than what I usually write. But please don't anybody whine at me that it's harder than usual to digest. I can't think of any better, shorter, or less complicated way to explain this. So here's today's dose of soapy chemistry --

I want to echo the thanks of others for your work on this amazing treatise! I just LOVE long explanations, the longer the better! I appreciate a mind like yours.

You are right, I thought soap was "a dry solid." What an eye-opening read this was! Super helpful - thanks a lot!

 

[Hendejm]

I know this is an older thread but I firmly believe this should be required reading for all new soapers (me included). Thanks to DeeAnna and all other contributors!

 

[DeeAnna]

I'm still around and willing to answer questions. Please feel free to keep this thread alive and ask your questions here.

In fact, re-reading this thread reminds me of stuff I've shared and have since forgotten. There was a thread started recently where the OP asked (paraphrasing here) why potassium soaps were more soluble in water than sodium soaps. I don't exactly remember the entire context of the question, but I think maybe Post 90 in this thread would have been a good one to share with the OP.

 

[melinda48]

This was a fascinating thread. I agree wholeheartedly, even though it is an older thread, all us newbies should read this!

 

[Steve85569]

A sticky version of this would be great (hint for the Admins).

Thanks again to DeeAnna for the chemistry and time spent on this and other posts.

 

[penelopejane]

I have made only a few batches of 95% NaOH with 5% KOH bar soap, so take my response with a grain of salt. No, it doesn't in such a low percentage. In a higher percentage it does, but that is also dependent on your recipe. As you can surmise, soaps with a higher percentage of hard oils would be less affected, whereas soaps with a higher percentage of soft oils would be more affected.

I tend to use more soft oils in most of my recipes and noticed a significant difference when I tried a 10% KOH/90% NaOH in softness of the resulting soap. I expect a long cure will solve the problem eventually, but haven't looked back at those particular soaps in a while, so don't yet know. I can only hope.

I have found that anything above KOH 5% makes a noticeably softer soap and a long cure (18 months plus) does not help at all.

 

[DeeAnna]

Yes, softness from KOH will be a permanent thing. I've left my KOH shave soap in the open air for months. It dries out and becomes more crumbly, but still remains soft.

 

[paragon]

@DeeAnna You wrote on your site that soap becomes milder after a lengthy cure, and everyone is telling me the same thing in another thread, but nobody seems to know why. Is this related to the changes in crystal/liquid phases which you described earlier, or is it another phenomenon?