Bars harden, but soap scraps/residue on jugs staying soft..... why?

[saddigilmore]

Hey, I just whipped up some soap yesterday, and something that always seems to happen to me has finally got me here to ask if you guys all experience the same thing, or have an explanation as to why this phenomenon is happening....

when beveling my fresh soap, the scraps are staying soft, even after days/weeks, some are still soft in my "scrap bag" from months ago... however the bars themselves, are rock hard after a few days.. Same goes for the soap batter I leave in my pots, to saponify to clean after 48-72 hours... they are "soft" and rinse off, but leave an oily residue, not completely cleanly, what I'd expect from fully saponified soap batter....

however, the bars themselves, even after 48 hours are rock hard, and if I try to lather up wit them, feel like regular soap... no oily residue...

why are the scapings/leftovers on the pots behaving so differently than the bars of soap themselves?? has anyone else experienced this?

Thanks all

 

[akseattle]

@saddigilmore , I actually have that experience, too. I haven't given it much thought- because I sometimes, when I get around to it, I press the scraps/ bits together into a little ball or rectangle. I have assumed it had something to do with the moisture in the air effecting the little soap bits differently than a bar. But, now you have me wondering ..... so, hoping one of the chemists on this forum might have an answer for us!

 

[Ekuzo]

I'm thinking of Newton's second and third law. Bars are hard when you touch or try to mold them with your fingers, because they have bigger mass/more material in their structure. The scrapes/shavings/drops are just too small/thin, have less mass and given the soap's structure just can't offer much resistance when you play with them/change their shape. Imagine just a little piece of snow in your palm, not even a proper ball, around 5 g let's say - you can break it or squish it, you can do whatever you want with it. Now imagine a proper, big snowball, something like 200-300 g. You can still make it change its shape or break it, bit it will be a lot harder to do so. Makes sense to me that way. Maybe if you're able to shave a little bit of a cured bar the small part will behave the same and will still feel kind of soft (even if the bar you took it from is hard)?

Edit: In addition, the conditions they're kept in play an important role as well. Maybe they don't get the chance to lose enough liquid and firm up properly? You mentioned the shavings are kept in a bag, on the other hand the batter leftovers are inside the jug (not enough airflow), while the bars are being properly cured on racks. JM2C

 

[saddigilmore]

the dirty jugs (what i pour batter from) are getting more airflow than the bars are, the soaps were put in a cardboard box, no rack. the jugs just sitting on the floor in open air. after 48 hrs, soaps are hard. jug leftovers, still puttylike.

the shavings/leftovers on the jugs aren't just soft because it is thinly shaved, it's like it will kinda melt if i rub it between my fingers. if i shave a bit off my cured bars, this won't happen.

it's more than the softness, it's also the way it behaves. it doesn't rinse clean, it leaves an oily residue

i'm puzzled.

 

[Ekuzo]

I still think bars in cardboard get more air than the rest, it's related to water loss as well as the consequential structural change. That among others, I think it's normal behavior.

With that being said, I can't say I've experienced the same. I don't let batter stay in my equipment, I clean it after usage. And I just recently made some soap balls out of shavings and crumbs, which I've kept in a plastic box with cheese cloth over it (no lid) to help with water loss. To give some background - I was initially going to make confetti soap, but I dropped the idea. They were sitting there for months and were really hard in the end - but even before that, they were still hard. Different shapes and sizes - tiny crumbs, shavings, along with small bits of soap and even some bigger chunks. I don't have such box now, I stopped cleaning the edges of my bars and generally I don't experiment that much now so I don't end up with leftovers like that anymore. It may not help particularly with what you're facing, it's just what I have experienced, just wanted to share