Making glycerin from scratch

[Nanditasr]

So I thought I'd make some glycerin, in order to apply all over the body -- while the co-created soap could serve as a dish bar. I tried it with just palmolein. I followed the recipe and directions given at https://www.wikihow.com/Make-Vegetable-Glycerin. I made 3/4 of the recipe given there, using about 330 grams of oil.

I made it last night, using my stand mixer. It took about 15 minutes to reach trace, and I added the salt and beat it on speed 1, just enough to blend it in. I then set it aside overnight, loosely covered, at room temperature (about 80 degrees F or 27 C) . However, this morning (about 16 hours later), I found that it was just a mass of moist, slightly soft soap -- not two layers. When I scraped it all and mixed it, it looked like coarse breadcrumbs. But it was super moist -- I was able to knead it with bare hands, and it did not sting. When I squeezed a ball of the 'dough', the glycerin dripped out of it. I applied it over myself, and it felt great, as glycerin does.

So, my questions are:

1. Why did I not get two distinct layers of soap and glycerin? What should I do differently?
   
2. With the mixture I now have, how best do I extract the glycerin? Or what other uses can I put it to?
   
3. Why are hard oils recommended for making glycerin? What happens if I use the same set of oils (mainly soft) I would use for making soap? Will I be left with a nice soft oil soleseife?!

Thanks!

 

[DeeAnna]

First thing, did you do any further research into this technique other than reading the Wikihow article? If you did other research, did you find information that suggested this article was a good method to follow? Did you run the soap recipe given in the article through a soap calculator to make sure the recipe was correct?

Why did I not get two distinct layers of soap and glycerin? What should I do differently?

You didn't get two distinct layers because the article doesn't remotely cover all you'd need to know to get this job done. That's why I never trust Wikihow articles.

For example, did you wonder about the many pictures in this article that just show a little pan filled with water with a few oil droplets floating on it? Doesn't that seem a little odd, since you know how soap should really look? If the author actually did this process, wouldn't you think the pictures should show the real thing?

With the mixture I now have, how best do I extract the glycerin? Or what other uses can I put it to?

Personally, I'd pitch it. You made some soap mixed with over 50% excess fat. The "glycerin" you're squeezing out is actually mostly water with some glycerin, salt, soap, and other impurities dissolved in the water.

Pure glycerin is NOT the end product of the process described in the article. The watery liquid (called nigre) must be purified to remove excess water, the salt, impurities, and the dissolved soap in order to get pure glycerin.

Why are hard oils recommended for making glycerin?

The article calls for coconut and olive. Is olive oil a "hard" oil?

What happens if I use the same set of oils (mainly soft) I would use for making soap?

Glycerin can be harvested from any soap.

Will I be left with a nice soft oil soleseife?!

This article is not describing how to make soap with a CP or HP method, which how one would make a soleseife soap. It's basically describing how to make soap with what's called a boiled method. The salt is largely removed from the soap with a boiled method -- the salt is dissolved in the nigre.

My tutorial about salting-out soap scraps shows how salt is used to separate soap from the nigre. If you want to adapt this method, you'd make new soap from scratch using an excess of water, then you'd follow my tutorial starting at the section "Salt-out the soap" to separate the soap from the nigre. You're on your own to figure out how to recover the glycerin from the nigre.

 

[Nanditasr]

Thanks, DeeAnna.

First thing, did you do any further research into this technique other than reading the Wikihow article?

I googled "how to make vegetable glycerin" and I found this and a few other (similar) links, including sciencing.com and motherearthnews.com.

Did you run the soap recipe given in the article through a soap calculator to make sure the recipe was correct?

Yes, but I figured the glycerin recipe would anyway have a significant water and oil excess (or lye discount) in order to produce the glycerin (compared to the amount of lye one would use to produce a regular 5% SF soap) -- isn't that the premise behind creating glycerin?

For example, did you wonder about the many pictures in this article that just show a little pan filled with water with a few oil droplets floating on it? Doesn't that seem a little odd, since you know how soap should really look?

The article calls for coconut and olive. Is olive oil a "hard" oil?

Indeed, I did notice the pictures and the olive oil. But when I saw several articles say something similar, I thought (hoped) it would work. I first looked on SMF for a thread, but could not find one about making glycerin from scratch; that's when I turned to these articles.

Glycerin can be harvested from any soap.

Thanks; good to know.

This article is not describing how to make soap with a CP or HP method, which how one would make a soleseife soap.

Which I have made in the past, and absolutely love.

My tutorial about salting-out soap scraps shows how salt is used to separate soap from the nigre. If you want to adapt this method, you'd make new soap from scratch using an excess of water, then you'd follow my tutorial starting at the section "Salt-out the soap" to separate the soap from the nigre. You're on your own to figure out how to recover the glycerin from the nigre.

Thanks; I'll certainly try that, esp. since your photos show a regular pot and not a crockpot. (I don't have a crockpot, but I assume I can use my stove-top Corningware?)

 

[DeeAnna]

Yes, but I figured the glycerin recipe would anyway have a significant ... oil excess (or lye discount) in order to produce the glycerin (compared to the amount of lye one would use to produce a regular 5% SF soap) -- isn't that the premise behind creating glycerin?

Ummmmm ... no. Think about it -- if you don't saponify the fat, then where is the glycerin coming from? I recommend you do some homework -- study the saponification reaction of fat and alkali and learn what this chemical reaction creates.

If your main goal is to create as much glycerin as possible with a secondary byproduct of skin-safe soap, you want to use a recipe with low superfat.

Again, I want to stress the water-based liquid (nigre) you will harvest is not even close to pure glycerin. The nigre you would get from the Wikihow recipe, assuming you modified it so the recipe actually makes soap, would only be roughly 20% glycerin by weight.

This last comment in the tutorial -- "...The vegetable glycerin should keep in the fridge for at least 3 to 4 weeks. You'll know that it has gone bad if it is no longer clear and instead appears cloudy. Glycerin that has gone bad may also develop a foul smell...." -- is a clue that the liquid isn't pure glycerin. Pure glycerin doesn't spoil.

"...I googled "how to make vegetable glycerin" and I found this and a few other (similar) links, including sciencing.com and motherearthnews.com...."

The Sciencing and Motherearthnews articles are just variations on the Wikihow tutorial -- just various bloggers all passing around pretty much the same info in different formats.

A reference provided in the Sciencing article gives a more accurate picture of how glycerin is recovered from nigre. "...After skimming off the soap, they are left with glycerin (and lots of “impurities” like partially dissolved soap, extra salt, etc.). They then separate the glycerin out by distilling it...." Too bad the Sciencing article totally ignores this vital point.

...since your photos show a regular pot and not a crockpot ... I assume I can use my stove-top Corningware?...

I suppose it would work, since people make soap in ceramic crockpots, but I can't say for sure -- this is not something I've studied nor tried.

edited to clarify my thoughts

 

[Nanditasr]

Ummmmm ... no.
Think about it ...
this is not something I've studied nor tried.
edited to clarify my thoughts

Thanks, and thanks for the edits.