Liquid Soap Questions

[Nao]

I wanted to sort of deepen my understanding of how to formulate liquid soap and I have a couple of questions that I couldn't find the answers to in the forum, although I might just not have looked close enough.

Anyway my first question is why so much castor oil? I'm fully aware of how and why it's used in bar soap at 5% and I don't understand why it shouldn't be the same way with liquid soap, is it because of the generally low amounts of oils rich in palmitic and stearic acid that other ways would have added some stability to the lather? I guess it would also act as a solvent to make clearer soap the same way it does in rosin soap?

Also have anybody tried diluting the soap with alternative liquids? Like koffee? Does it require a preservative or would the concentration of soap still be high enough to not let things grow in there? Would the scent survive? For what it's worth I was planning a dilution ratio of 1 part paste to 0,75 part water.

I usualy formulate my bar soap with 10% rapeseed oil wich works fine most of the time and I like what it adds to the soap but I'm under the impression that it might be more prone to rancidity in liquid soap than in bar soap. Does anybody have any experience with that?

I know I really should just experiment myself but I want to stretch what little KOH I have left since i have spent such ridiculous amounts of money on soaping stuff recently and can't buy more for a while.

 

[bathgeek]

My liquid soap is 100% olive oil based. You don’t need castor oil if you don’t want to use it. I’m not aware of anything special castor oil does for liquid soap. I know it’s great for shampoo though.

 

[Susie]

I lack the reason why, but castor oil acts differently in liquid soap. You will want more of it. I am sure DeeAnna will be able to explain.

You need to only dilute with water. You will encourage bacterial growth with anything else.

Your dilution amount depends on the oils used. You will find that paste made with some oils take much more water to dilute than you expect.

 

[Arimara]

I lack the reason why, but castor oil acts differently in liquid soap. You will want more of it. I am sure DeeAnna will be able to explain.

You need to only dilute with water. You will encourage bacterial growth with anything else.

Your dilution amount depends on the oils used. You will find that paste made with some oils take much more water to dilute than you expect.

Case in point, if you made a soap with a high amount of olive oil, you may need way more water than you would for a coconut oil soap or many other soaps for that matter. :think:

 

[Ford Prefect]

I agree with Arimara. If you use anything other than distilled water to dilute, there is a potential health issue. Don't risk it.

 

[Zany_in_CO]

...Anyway my first question is why so much castor oil?...

Your guess is as good as mine! Maybe it's just because you can! LOL In all the years I've been making LS, I'm hard-pressed to think of one where I've used castor oil. As Bathgeek said, it's good for lather and conditioning in shampoo and, unlike hard bars where using too much can make the bar sticky, it behaves differently in LS, as Susie said, and you can use as much as you like. It also boosts lather in all-liquid-vegie-oils that are lacking in that aspect.

I guess it would also act as a solvent to make clearer soap the same way it does in rosin soap?

It's not a solvent, nor IME does it behave like one but it is thick and clear and helps with the color and viscosity of the final result. Oh, now that you mention it, it does play nice with Rosin tho, so you may be onto something there. From my notes: Rosin at 5%-15% makes incredibly clear amber brown LS with awesome lather. Adds transparency and emollience and acts as a preservative as well. It saponifies much like an oil but without any resulting glycerin. It gives a smooth cold cream finish to the lather and also acts as a detergent and preservative. Can be sensitizing.

Also have anybody tried diluting the soap with alternative liquids?

Feel free to try alternative liquids to make the lye solution. For dilution, water is your best bet.

Does it require a preservative or would the concentration of soap still be high enough to not let things grow in there?

Fully-saponified soap requires no preservative.

Would the scent survive?

Yes.

I was planning a dilution ratio of 1 part paste to 0,75 part water.

The dilution ratio is mostly a matter of personal preference. That being said, the general rule of thumb is to use 2-3 times the amount of oils/fats in the formula for the amount of dilution water. The two extremes are Coconut Oil vs. Olive Oil. Coconut Oil will stay suspended at 40% paste in 60% dilution water; Olive Oil at 15% in 85% dilution water. This results in thin LS, but with great lather! All other oils and combos fall somewhere in between.

I usualy formulate my bar soap with 10% rapeseed oil -- Does anybody have any experience with that?

I've never soaped it, but Saponificarion is a big fan of rapeseed oil. Perhaps she'll weigh in.

I know I really should just experiment myself but I want to stretch what little KOH I have left since i have spent such ridiculous amounts of money on soaping stuff recently and can't buy more for a while.

I hear ya! Try making small batches using 12 oz. oils. This results in approx. 16 oz. of paste, that you can then divide into 4 portions and experiment to your heart's content.

HTH :bunny:
​

 

[Saranac]

Due to it's high ricinoleic acid content, castor oil is a unique FA in that it acts as both an oil and an alcohol. As such, it saponifies quickly into a soap that is very soluble. When used in LS, it helps to soften the paste and it adds clarity to the finished diluted soap.

Also, as Zany notes, it's great for melting rosin into as the solvent-properties of the castor seem help speed things along--at a lower heat.

I've never used rapeseed, but I once used canola (which is related) as the bulk of my LS. I never had a problem with rancidity, and due to its low amounts of palmitic/stearic acids, I found it made a very clear soap. However, in an effort to get the most bang for my buck, I switched to HO sunflower as I use that in my bars and lotion.

 

[cherrycoke216]

Fully-saponified soap requires no preservative.

Yes.

Zany, I think there's a debate regarding preservative after dilution. But if you mean soap paste, then I agree with you.

 

[Susie]

Actually there is no need for preservatives after dilution. Some soapers use preservatives, some don't. I don't, but if I sold, I would use it as there is no telling what customers will do to their liquid soap.

I had a small bottle of liquid soap for almost 3 years before I could find yuckies growing in it under a microscope. I suspect it was from sticking the pipette in it, but I can't prove it.

You need to only make as much as you can use in a reasonable amount of time...say 3-6 months worth if you are not going to use a preservative. This is presuming you only use distilled water to dilute, like you should.

 

[cherrycoke216]

Actually there is no need for preservatives after dilution. Some soapers use preservatives, some don't. I don't, but if I sold, I would use it as there is no telling what customers will do to their liquid soap.

I had a small bottle of liquid soap for almost 3 years before I could find yuckies growing in it under a microscope. I suspect it was from sticking the pipette in it, but I can't prove it.

You need to only make as much as you can use in a reasonable amount of time...say 3-6 months worth if you are not going to use a preservative. This is presuming you only use distilled water to dilute, like you should.

Mmm...may I ask why you stick a pipette in?
3 years, that's a good news for hobbyists.

 

[Nao]

Yes, of course. Susie and Zany, I was planning on trying Irish Lass' high olive oil liquid soap recipe and that was the ratios she used, I should have mentioned that too.

Saranac that's great to hear, I will add rapeseed to my liquid soap recipes without worry then.

 

[Susie]

Mmm...may I ask why you stick a pipette in?
3 years, that's a good news for hobbyists.

How else was I to get out one single drop to put on the slide?

 

[Zany_in_CO]

I was planning on trying Irish Lass' high olive oil liquid soap recipe and that was the ratios she used, I should have mentioned that too.

I should have mentioned this earlier... there are as many different ways of making liquid soap as there are liquid soap makers! LOL When it comes to making IL's LS, she's the expert and the best person to answer your questions.

Best of Luck and Happy Soapiing!

 

[cherrycoke216]

How else was I to get out one single drop to put on the slide?

Haha! I wasn't really thinking. So you kept doing it since day 1 and watching closely every month? Kudos to you for the scientific method.

 

[jcandleattic]

Actually there is no need for preservatives after dilution. Some soapers use preservatives, some don't. I don't, but if I sold, I would use it as there is no telling what customers will do to their liquid soap.

I had a small bottle of liquid soap for almost 3 years before I could find yuckies growing in it under a microscope. I suspect it was from sticking the pipette in it, but I can't prove it.

You need to only make as much as you can use in a reasonable amount of time...say 3-6 months worth if you are not going to use a preservative. This is presuming you only use distilled water to dilute, like you should.

Mine grew 'yuckies' after diluting with distilled water in about 3 months. I will always use a preservative in diluted liquid soap.