jesfayven
Well-Known Member
So there is some confusion about the actuality of the crystalline structure that occurs with curing. Some people say it’s a myth and others say it’s real. Can the chemists on here chime in?
Curing
- Thread starter jesfayven
- Start date
Help Support Soapmaking Forum:
A
amd
https://www.wholesalesuppliesplus.com/handmade101/learn-to-make-articles/crystal-power.aspx
http://cavemanchemistry.com/HsmgTemperature2009.pdf This one has a lot of info, but start on pg 56 if you don't want to read the whole thing.
http://cavemanchemistry.com/HsmgTemperature2009.pdf This one has a lot of info, but start on pg 56 if you don't want to read the whole thing.
I've been wondering this too. The soapmaking FB groups I'm part of keep saying that soap developing a crystalline structure has been "disproven" and that cure time doesn't matter except for moisture loss. I'm glad you asked and will follow this thread.
I read this article this morning, and it makes sense to me: Curing soap | Soapy Stuff
I read this article this morning, and it makes sense to me: Curing soap | Soapy Stuff
A
amd
I'd be curious to see their scientific data supporting this.
By definition A crystalline structure is any structure of ions, molecules, or atoms that are held together in an ordered, three-dimensional arrangement. My understanding is that anything that is a solid has a crystalline structure. In humans, our bones and teeth have a crystalline structure. This is why it is important to eat supplemental foods and minerals for our bones, because as we age that crystalline structure changes. You can apply this to soap as well, as it cures, it loses moisture and the crystalline structure changes to adjust to the moisture loss. Many experienced soapers who have years worth of soaps will confirm that moisture loss (and soap weight changes) continues during the life of a soap, and the crystalline structure changes during the life of the soap as well.
jcandleattic
Well-Known Member
I'd be curious about this too, as it seems the group moderators or admins of that (those?) groups have no idea about soap IMO.
This is why I'm not in a lot of soapmaking groups on FB. The majority of them are so full of misinformation to the point of almost being harmful, it's hard to watch, so for me it's better to not even be a part of them.
That makes sense to me. The people on the FB groups haven't shown their reasoning, they have just said to read Kevin Dunn's book. Which I plan to at some point, but it's out of my price range right now.
It does often seem that some of the information is a little sketchy.
A
amd
This confuses me because I believe that Kevin Dunn supports that curing is more than water loss.... so reading the book would not support what they are saying.
Cat&Oak
Well-Known Member
Scientific Soapmaking is an amazing book I highly recommend it.
I would certainly love to read it at some point!
The only thing this newbie knows, is my soap feels nice at 2 weeks, but great at 7 weeks. And right around then, the physical hardness increases in my recipe too.
I've been soaping for almost 20 years and this is the first and only time after a 3 week cure I can squish the soap...still soft. in room with dehumidifier and open air. what would cause this? same recipe I always use
jcandleattic
Well-Known Member
Lots of things. It could be a different supplier for the oils, different atmospheric pressure in the weather, maybe you were on automatic and left out an oil by mistake, the dehumidifier is full or not functioning properly. There's really no way to tell with the little amount of information you've given, but could be any number of these things.
DeeAnna has an excellent explanation of crystallization in the article.
Imagine when you first make a soap. Your oil or butter is shaped like a capital E with a glycerol molecule as the backbone and 3 fatty acids attached to it. The sodium ion from NaOH attacks the structure. The glycerol backbone breaks away and the sodium ion attaches to the end of the fatty acid to form a fatty acid salt. This is the saponification step. If you was with a soap at this stage, it may bubble but it will be harsh and not last long. Now the water starts to evaporate. As it evaporates, the fatty acid salts start to line up and start crystallizing. As time goes on, more and more water evaporates. The crystal structure becomes more orderly and condensed. It doesn’t ever completely stop becoming more orderly and condensed so that is why a year old bar may last longer / be milder than a 3 month bar.
That makes perfect sense to me. I don't understand why so many people say it's not true. I've read DeAnna's article several times and it makes sense. I refer to her site quite often.
I cannot agree with you more and have often wondered why the admins of these groups don’t correct the misinformation. I have tried to steer people in the right direction and usually get attacked for it! I keep quiet for the most part now (my tongue is too sharp). I’d end up getting kicked out.
jcandleattic
Well-Known Member
I just leave. I can't tolerate the spread of misinformation if I know for an absolute surety the information is incorrect. If people want to stay ignorant, that's their prerogative, but I don't have to stay and be a witness to it once I've had my say. LOLI’d end up getting kicked out.
Microchick
Well-Known Member
i know theoretically this sounds right but Pg 79 of Scientific Soaping by Dr Dunn says 3 things occur during cure. Evaporation, hardening, and leftover alkali is neutralized. Nowhere can I find him talking about crystallization changes. Has anyone tested the theory by imaging slices of soap over time?
SoapDaddy70
Well-Known Member
I stay in the one Facebook group I am in just for entertainment purposes. I gave up being part of discussions because its not worth my time but there sure is some funny stuff being posted. Some of the questions sound like they are coming from a toddler.
You have only to Google "crystalline structure of soap" to understand that it is real. You can also Google "is the crystalline structure of soap real" to find even more support.
And you have only to look at commercial soap labels (and even artisan soaps who don't want to use the word "lye" or "sodium hydroxide") to see that soap is compromised of the salt (a crystalline structure) of a fatty acid ie Sodium Tallowate, Sodium Palmate, Sodium Cocoate, Sodium Palm Kernelate, etc.
And you have only to look at commercial soap labels (and even artisan soaps who don't want to use the word "lye" or "sodium hydroxide") to see that soap is compromised of the salt (a crystalline structure) of a fatty acid ie Sodium Tallowate, Sodium Palmate, Sodium Cocoate, Sodium Palm Kernelate, etc.
The caveman chemisty link @amd linked above is written by Dr. Kevin Dunn, author of Scientific Soapmaking: The Chemistry of the Cold Process, so if you read that page 56 that @amd mentions, I think it is obvious that he is talking about a crystalline structure. And on page 73 of that same link, Kevin says, "The structure of solid soap is similar to that of neat soap, but the fatty tails of the soap molecules are “frozen” in a crystal lattice." That, too is a crystalline structure, as further stated by @amd above and supported by DeeAnna's explanation that @MrsZ linked in her response.
So I don't quite understand how a anyone could say, "Just read Scientific Soapmaking" and claim it proves the opposite of what Kevin Dunn says in his other information easily accessible online. I do have his book and have not found a contradiction to what he says on his Caveman Chemistry site. So if they can specify a particular quotation, page and reference in his book, I'd be eager to look it up. ETA: Saying that those 3 things happen as Microchick mentions above does not preclude the other things that Dr Dunn says in the Kevin Dunn soap lectures I have attended in person & pdf linked by amd in her first post in this thread.
Dr. Dunn has lectured extensively and not everything appears in his book in as much detail, as some of his lectures, so by saying something is disproved by its absence in a given book is ludicrous.
Here are a couple of links that address solids with or without crystalline structure:
https://opentextbc.ca/chemistryatomfirst2eopenstax/chapter/lattice-structures-in-crystalline-solids/https://chem.libretexts.org/Bookshe..._According_to_Its_State-_Solid_Liquid_and_Gas
The second talks about glass as amorphous rather than crystalline. So I suppose an argument could be made that soap is an amorphous solid like glass rather than crystalline solid, but even Kevin Dunn talks about the crystalline structure in the pdf @amd linked, so I am not sure that would reconcile. However, it is possible to convert a crystalline solid to an amorphous solid according to Britannica and other sources, and heat is part of that process. So I suppose that solid soap could become amorphous after the crystalline phase given sufficient heat.
Here is a link that shows how amorphous solids break versus how crystalline solids break, and I did once have a soap that fit that criteria quite dramatically. But does it all? I am not at all sure. I believe that one soap that broke like Obsidian (volcanic glass, an amorphous solid) breaks had something to do with the ingredients and how long I waited before attempting to cut the soap. But then, maybe that is a clue? I am unsure.
Although I am not a chemist, I am aware that something can start out with crystalline structure and end up amorphous solid and that amorphous solids can also be converted to crystalline solids (link). So is solid soap one of those things? Does it start out crystalline and stay crystalline? Or does it start out crystalline and become amorphous? Or are both or either possible depending on conditions? In the NIH article that I linked (a couple of sentences back), it states that both can co-exist, so could that be the case with soap?
I suppose that all are possible, but is it really that crucial to know or argue about? Maybe for the nit-pickers.
Similar threads
