What actually happens during the "cure" period?

[Saltynuts]

I've seem tons of people say you need to cure your soap, for a few days if its hot processed or like 3 weeks if its cold processed. What actually happens during that curing period? I see people say it gets "milder". But I watched a youtube video the other day where the lady filming it said that there was some speculation that during the cure period that the particles in the soap went into some matrix or crystallized more or something like that (can't remember exactly), but then she said she talked to a couple scientists on this and they said that didn't happen, the only thing that happens during the cure period is that water evaporates.

So what really goes on during the cure period? In my mind, if the saponification is complete in cold processed soap in a couple days, then there are no further chemical reactions going on after that, and any other waiting is indeed just waiting for water to evaporate out. Unless some totally other chemical reaction starts happening, but I've never heard anyone say that.

Thanks!!!

 

[Cat&Oak]

Here is an article that explains the crystallization theory I don't know if it is a thing but it sounds convincing

https://classicbells.com/soap/cure.asp

 

[cmzaha]

I will mention I have seen the difference in the crystallization structure in a slice of new soap versus a long-aged soap. I wanted to post pics but my granddaughter never got it done for me. So soap does change as it ages. Next year when I am finally moved and settled I will hopefully try again to log and post pics of varying ages of soap.

 

[The Efficacious Gentleman]

Alone from what is confirmed (water loss) there has to be a structural change in the soap. If the soap has water and the water is no longer there, there is a change to how the soap is structured, which we see in that the soap also shrinks to some degree during a cure.

And I am of the view that from water loss alone a hp batch needs as much if not more of a cure as cp soap. I always found my hp bars at 4 weeks don't last as long as cp bars at the same age. Older hp bars last much longer.

 

[ResolvableOwl]

@cmzaha Ahh yes, the microscope pics …

she talked to a couple scientists on this and they said that didn't happen, the only thing that happens during the cure period is that water evaporates.

Dodgy scientists. It is very true that water evaporates during cure time (when you decide to declare it finished is another topic). But it is a bold hypothesis to claim that nothing else happens, and if they really were good scientists, they should present data that proves so, or at least reference those who have made studies before that corroborate that the only difference between young and cured soap is the water content.

https://www.ultimatehpsoap.com/post/the-hot-process-cure

 

[Jen74]

I will say that I am trying to figure out the whole curing thing myself. I usually cure mine for 5 to 6 weeks. However, I will say when I use my soaps at the 6 week mark, they do not change much at all after that. Meaning each bar lasts the same amount of time. I make HP soap, and will say it hardens WAY quicker than CP. My CP soap would stay soft for a longer period. This probably depends on the oils used too. I only use Palm oil and palm kernel so maybe that is why they harden quicker than if I used olive oil or coconut ( which I cannot as I am allergic). Those would likely take longer due to the high fat content? Just my guess, I am definitely no expert

 

[ResolvableOwl]

There are indeed many strange things, that might not even be apparent to someone not paying attention to every detail. Somehow everyone's results may differ or not, and there isn't always a good explanation for that. I for example had not much luck to get any agreeable hardness from palm oil in HP. CP is fine, but HP bars with palm oil as the only hard oil would stay soft and sticky forever.

In this respect, you are an expert, at least for your own small world of soaps. If something works better for you than for someone else, do it – there is nothing wrong. Things only start to become complicated when you want to understand why something works better than something else, but there is contradictory evidence.

 

[Jen74]

There are indeed many strange things, that might not even be apparent to someone not paying attention to every detail. Somehow everyone's results may differ or not, and there isn't always a good explanation for that. I for example had not much luck to get any agreeable hardness from palm oil in HP. CP is fine, but HP bars with palm oil as the only hard oil would stay soft and sticky forever.

In this respect, you are an expert, at least for your own small world of soaps. If something works better for you than for someone else, do it – there is nothing wrong. Things only start to become complicated when you want to understand why something works better than something else, but there is contradictory evidence.

This is interesting. I can only use palm oil and palm kernel oil in my soaps ( I am allergic to other oils). I make mine HP and the soap is always hard. For me when I made it using the CP method, it did stay on the softer side.