My new favorite way to rebatch scraps

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dragonmaker

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I haven't done the math to figure if it's cost efficient, but I loved my experiment! I found a spray hand sanitizer that is 66% ethanol, the rest being deionized water and glycerine, and wanted to experiment with using it to rebatch soap. I took all my scraps from a year of soaping, put them all in a heat-safe container, then thoroughly wet down the scraps, with a little standing liquid in the bottom of the container. I wrapped the top up tight with heat-safe plastic wrap and microwaved on and off with a lot of stirring inbetween, and the soap dissolved easily and became pourable, like melt and pour! Now I have a batch of solid bars drying instead of a quart ziplock of scraps too small to be easily used. I'm going to let the ethanol and extra water evaporate out for 6 weeks, and see how the bars feel after that. I love chemistry!
 

ResolvableOwl

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for 6 weeks, and see how the bars feel after that.
Patiently watching!

I personally dislike having noticeable ethanol in soap. It is super helpful for dissolving and M&P, but the skin feel reminds me too much of too high CO levels and cheap hand sanitisers. Usually, alcohol-containing soap is wrapped to avoid evaporation, the more curious I am if leaving them open for “cure” makes them behave.

Don't forget to weigh them before/after (and if possible measure their size)!
 

dragonmaker

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In this case, I don't want a melt and pour soap in the end. I just want soap that isn't in powder or tiny shred form, so I figure letting the ethanol evaporate will let it become more like a normal soap.

I forgot to weigh them yesterday! I'll have to do that today and post here.
 

dragonmaker

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@lianasouza I think so... Ethanol is the same alcohol in alcoholic drinks. You can end up heating the soap and ethanol mix up to the ethanol's boiling point, and then it can boil out, but that's why I wrapped it tight with heat-safe plastic wrap to try and hold in any vapors, and allow it to condense and drip back in as it cooled. In the presense of a spark it might catch on fire, but with no metal in the heating chamber, I didn't have any sparks available that I know of. I also had it wrapped tight to try and contain any vapors coming off the mixture, so even if there was a spark, it shouldn't have reached the alcohol.

Do you know of something else that could have gone wrong? I'm willing to learn.
 

lianasouza

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Not really, all the precautions you took seem to make sense. I am glad it turned out nice and would love to know how the bars are in 6 weeks!
 

Ugeauxgirl

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Did the glycerin add anything to it? Do you think the result would be the same if you just used everclear (drinking alcohol) and distilled water instead? Fun experiment. Can't wait to hear how it turns out!
 

dragonmaker

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If I remember correctly, glycerin is also a solvent for soap just like alcohol, which is why it's added to melt and pour. It won't evaporate away like the ethanol and water, but there's glycerin naturally in homemade soap as a by-product of turning fats in to alkaline salts of fatty acids (soap). I'm guessing it will inhibit the lather some, but it won't make the soap more harsh. Glycerin is part of what makes homemade soap nicer than store bought soap where the glycerin is removed to be added to lotions or whatever. It's a humectant, so it attracts water. Too much glycerin will make the soap sweat, but I'm guessing there isn't much glycerin in the spray. Asssuming it's the same as food labeling, when the ingredients are 66% ethanol, then deionized water, then glycerin, there has to be less glycerin than water, so there's less than 17% glycerin by weight in the mix.
 

dragonmaker

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Well, it’s been longer than 6 weeks, but I did cure those soaps, so here’s pics and an 9 month later update of my rebatch scraps + ethanol soap experiment:
They lost a ton of volume and no longer smell like ethanol. All were poured into individual cavity molds, either rectangle bar shapes or cupcake shapes. The micas all seem to have fallen to the bottom of the bars. The leftover color is probably from the variety of fragrance oils in the mix. When you pour the bars, a skin forms almost immediately and any bubbles are forever frozen on the top.
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dragonmaker

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Lather update: this might be my very favorite bar! Or at least tied with my favorite bar of soap! I’m in shock! I did not think it would lather so well, but it’s quite lovely. I worried that too many solvents would stick around and suppress lather like in my kids’ melt and pour soaps, but it’s nothing like them. It’s like my very best well-cured well-formulated soap (which was actually a small portion of what went into these rebatch scrap soaps). I’m getting thick lather with both fluffy and creamy bubbles. I do wonder a little if the shape is influencing the lather ability or not, but I also tend to rub the bar a little, then just rub my hands together to see how the lather behaves instead of continuing to rub the bar, and the lather is not collapsing or fading away like some I’ve tested. It has some staying power.
 

lsg

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If I remember correctly, glycerin is also a solvent for soap just like alcohol, which is why it's added to melt and pour. It won't evaporate away like the ethanol and water, but there's glycerin naturally in homemade soap as a by-product of turning fats in to alkaline salts of fatty acids (soap). I'm guessing it will inhibit the lather some, but it won't make the soap more harsh. Glycerin is part of what makes homemade soap nicer than store bought soap where the glycerin is removed to be added to lotions or whatever. It's a humectant, so it attracts water. Too much glycerin will make the soap sweat, but I'm guessing there isn't much glycerin in the spray. Asssuming it's the same as food labeling, when the ingredients are 66% ethanol, then deionized water, then glycerin, there has to be less glycerin than water, so there's less than 17% glycerin by weight in the mix.
Propylene Glycol is also used as a solvent.
 

Carly B

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Forgive my cluelessness, but why do you need a solvent? Although I make CP soap now, I have made rebatch for years by choice (I would buy soap shreds). I like my rebatch because I can use fragrances that normally accelerate and I can use oils my skin loves without them being damaged by lye. But I've only every rebatched with heat (in the microwave) and additional liquids (aloe, goatmilk, oatmilk) and oils and sometimes exfoliants. Packed it into single cavity molds,
and popped out when they cool.

Never thought about using a solvent. What does it do?
 

dragonmaker

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@lsg True, but in this particular case I wanted most of the solvents to evaporate away in the end instead of sticking around like propylene glycol does

@Carly B You don't NEED a solvent. It's mostly a silly experiment, purely because I felt like it. However, I've always heard that rebatching with heat is hard to get smooth and tends to look chunky when it's in the middle of the process. I have texture issues sometimes and didn't think my mental illness would handle seeing/feeling that well, so I went for finding a process that looks like colored water when poured instead of my assumed guess of thick and gloopy for a more traditional heat rebatch. If I'm wrong about the texture throughout the process, please let me know!
 

Zany_in_CO

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CONGRATULATIONS! :winner:

I taught this technique in 2004 -- long time ago. I lost most of my notes. If interested, I might try it again. I've long wanted to make a dupe of Pears (transparent) Soap. Maybe after the holidays?

Well, it’s been longer than 6 weeks, but I did cure those soaps, so here’s pics and an 9 month later update of my rebatch scraps + ethanol soap experiment:
A 3-month cure is typical of a Rebatch with Ethanol. BTW, I use 190 Proof Everclear. Is that what you used?
The micas all seem to have fallen to the bottom of the bars.
With this technique, it's watery. Not enough viscosity to suspend the mica.
They lost a ton of volume and no longer smell like ethanol.
Also typical.
When you pour the bars, a skin forms almost immediately and any bubbles are forever frozen on the top.
A skin forms? Perfect! No sense trying to remove it, it will just reform as many times as you try. I keep a bottle of spray alcohol handy to lightly spritz the bubbles on top to make them disappear. :thumbs:
I worried that too many solvents would stick around and suppress lather
That's true... ethanol is known to boost lather. If you use too much, it flattens the lather.
I’m getting thick lather with both fluffy and creamy bubbles.
Typical. Ain't it great? 😅
True, but in this particular case I wanted most of the solvents to evaporate away in the end instead of sticking around like propylene glycol does
:thumbs: I don't use propylene glycol at all. It stings my hands so I avoid it.

If you want to evaporate the solvents, don't cover with plastic wrap. (That may be why your bars are concave. ???) I used an 8-cup Borosilicate Pyrex; only 8 ounces of shreds; toss to wet all with solvents; Nuke 5 minutes on HIGH.

Watch as the batch eventually rises all the way to the top. Stop before it spills over. Let it rest in the MW for 5 minutes. At that point, you can push aside the film to add fragrance and a drop of food coloring if you wish.

It's really exciting! NOT for the faint-hearted!!! :nonono:
 

dragonmaker

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@Zany_in_CO I didn’t want the ethanol evaporating away in the microwave, so it wouldn’t be a fire hazard, so I kept it tightly covered while in the microwave. I left them on drying racks for months to allow for thorough evaporation afterwards. I assumed it would look funny after evaporation. I don’t mind the concave look, it’s just using up scraps for home use. Didn’t Pears soap have a concave top because of evaporation? I’d heard that was part of their look.

I did not use Everclear. I used ethanol spray sanitizer (66% ethanol, the rest deionized water and glycerin) that I found at a hardware store. It comes in a spray bottle, so it was easy for me to wet down my scraps quickly.
 

Zany_in_CO

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Didn’t Pears soap have a concave top because of evaporation? I’d heard that was part of their look.
Gosh, it's been so long, I don't remember that. 🤔 Hmmm.
I used ethanol spray sanitizer (66% ethanol, the rest deionized water and glycerin) that I found at a hardware store. It comes in a spray bottle, so it was easy for me to wet down my scraps quickly.
Interesting. Thanks!
 

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