Doesn’t all soap float?

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Unless you whip air into it... we had a floating soap challenge a while back.

okay, I’ll look back on that. I guess I was thinking that soap being mostly oil would mean that the only reason it doesn’t float is that there’s still a bunch of water in the bar that could evaporate out. But now I’m guessing that theory is way off and I’m about to learn all about it 😂
 

TheGecko

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okay, I’ll look back on that. I guess I was thinking that soap being mostly oil would mean that the only reason it doesn’t float is that there’s still a bunch of water in the bar that could evaporate out. But now I’m guessing that theory is way off and I’m about to learn all about it 😂

Oil floats if it is free oil. Once saponification occurs, the oils are no longer “oils”, but are now soap and soap is heavier than water and so it sinks.

It takes years for water to fully evaporate from soap.
 
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DeeAnna

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Your logic is fats float on water therefore soap should also float. But don't forget the NaOH; it's MUCH more dense than water. Have you included this into your chain of thought?

But, honestly, you can't just look at the ingredients that go into a chemical reaction and draw sound conclusions about the behavior of the final product.
 

mishmish

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I read an apocryphal story that Ivory Soap was invented when an apprentice forgot to turn off a mixing machine and beat a lot of air into the soap. Instead of declaring the batch ruined, it became the big selling point. Back in the '50's my great uncle used to take a bar of floating Ivory soap to the "crick" to bathe while we kids swam.
 

shunt2011

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I read an apocryphal story that Ivory Soap was invented when an apprentice forgot to turn off a mixing machine and beat a lot of air into the soap. Instead of declaring the batch ruined, it became the big selling point. Back in the '50's my great uncle used to take a bar of floating Ivory soap to the "crick" to bathe while we kids swam.
We used it when camping and bathing in the lake growing up. Because it did float.
 

earlene

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No, not all soap floats. Just test it out. Fill a tub with water and drop in a bunch of bars of soap. Most bars of my soaps stay on the bottom of the tub except the soap I made using the salted out method. I've never made whipped soap.
 

DeeAnna

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The other way to make a floating soap besides whipping the batter or salting-out the soap is simply to melt the soap, exactly like you'd do a rebatch. You basically want to heat shredded soap with a minimum of added liquid -- keep heating and stirring. Add a bit of water every so often -- just enough to keep the soap from drying out. When the melty soap gets hot enough, it will puff up a little bit. If you pour it into a mold at that point ... voila! ... you end up with floating soap. That's how I did my floating soap for the March 2016 SMF Challenge.
 

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