Cream Soap dehydration

[KayMay]

Hi, I have made quite a few batches of cream soap, and I am really happy with my recipe. Is there any kind of additive that will keep the cream soap from turning to a (soft) solid. This only happens if the lid is left off the container, but not everyone puts the lid back on after use.

 

[Zany_in_CO]

Hi KayMay and Welcome!

Unfortunately, there aren't a lot of cream soap makers on the forum to answer your question directly, but you may find this thread helpful.

A CREAM SOAP TUTORIAL

It runs from 2014 to 2021 with @ResolvableOwl picking up the baton and giving the technique a test drive and may have some advice for you.

 

[KayMay]

Thanks, there doesn’t seem to be many cream soap makers anywhere. I have read (I think) every cream soap thread on the forum, and haven’t had any luck finding an answer. I guess I will have experiment myself. Ugh everything to do with the cream process takes sooo long, I was hoping for a quick answer. Lol I guess I will have to find some patience.

 

[ResolvableOwl]

Oh dear! Yes, the Lindy cream soap. “Rotting” time is about over right now. @KayMay I'll be your shortcut into that “patience” thingie that everyone is talking about (and kudos to @Zany_in_CO for remembering/reminding me when the time has come for the cream soap to be ready to give it a shot )

 

[Zany_in_CO]

@KayMay If anyone can figure it out for you, I'd bet money on @ResolvableOwl ! In addition to having a brilliant brain she enjoys a challenge like the rest of us enjoy as little challenge as possible!

 

[Cat&Oak]

I bow to you! Cream soap is not easy! Please keep us abreast of your journey

 

[DeeAnna]

Cream soap is water based, so if a person leaves it uncovered, it's gonna dry out.

People complain about this happening to liquid soap as well and want a surefire cure to keep liquid soap from getting a dry skin on the top of the soap in an uncovered jar or getting "soap snot" on the nozzle of a pump dispenser.

Ditto with shaving soap which is a variant of cream soap, especially the "croap" style of shaving soap.

Unless you can figure out a way to entirely replace the water with glycerin or other solvent that doesn't evaporate, this is going to be an inevitable aspect of cream soap. If consumers won't follow your advice to keep the soap in a sealed container, there's not much more you can do.

 

[KayMay]

Thanks DeeAnna,
I wondered whether liquid soap would be the same (I haven’t ventured down that rabbit hole yet). I was looking for something to replace some of the water, but not affect the lather. I am guessing it doesn’t exist.

 

[DeeAnna]

Cream soap and many shave soaps/croaps are basically liquid soaps made with very high % of stearic and palmitic acids. Typical liquid soaps have low % of these two fatty acids. I realize it's tempting to treat these soaps as being wildly different, due to their different appearance and the different ways they're used, but honestly they're close kissin' cousins, chemistry wise.

Adding more stearic acid (aka supercream) to cream soap after saponification helps to thicken, stabilize and perhaps increase the mildness of the soap. Adding glycerin after saponification also changes the fluidity and texture. You can do these things to liquid or shave soaps too and get similar results.

The long period of curing a cream soap (I refuse to use the word r*t) is to allow the crystalline structure of the soap to form which alters the texture. This texture change happens even in a closed container (no evaporation), which should boggle the mind of any bar-soap maker who believes curing soap is only due to the simple loss of water from soap due to evaporation.

Any soap -- cream, shave, liquid, or bar soap -- will lose water by evaporation if you leave it exposed to the open air at typical humidity levels. It's just a fact of physics and chemistry. Evaporation is prevented by keeping the soap in an enclosed container.

 

[lianasouza]

Can anyone discreetly whisper me the r*t word she refuses to use?

 

[DeeAnna]

The word is "rot".

Not sure why one would use this word to describe curing cream soap, but no one asked for my opinion when they came up with this idea.

 

[Zany_in_CO]

This only happens if the lid is left off the container, but not everyone puts the lid back on after use.

I was looking for something to replace some of the water, but not affect the lather. I am guessing it doesn’t exist.

The problem is not the product; the problem is the end user, IMHO. If t'were me, I would put something on the label like "Keep covered when not in use to prevent dehydration" or similar.

 

[ResolvableOwl]

@KayMay
We know very little about the recipe(s) you're using. So it is difficult to provide starting points for modification.
For now, I assume that your cream soap is similar to @Lindy's that @Zany_in_CO has linked above: Dual-lye HP soap (oleic/stearic/lauric FAs) with a generous excess of superfat (post-cook addition of stearic acid).

I am trying to understand your woes. Not sure if my Lindy cream soap replica gives you any insights (I've kept it for ripening airtight for 7½ months – I'll post a review of it tonight, but not here):
You are unhappy that your cream soap solidifies quickly when left open.

Several thoughts on this:

• “Hardness” of an essentially LS recipe can come from several compounds that are present in the soap. Anions: stearate > palmitate > laurate > oleate > PUFA. Cations: FFA > sodium > potassium. So you could shift the recipe to a softer, less hardening-prone composition by going right in these rows; i. e. replace stearic acid by palmitic acid (e. g. replace shea butter by cocoa butter or palm oil), or allocating less lye to the NaOH side, in favour of more KOH.
• Hygroscopic additives. (Closest to your original idea) Polyols come to my mind. You can try out how far you can push the addition of glycerol and/or sorbitol/xylitol. But too much polyols (& too little water) can turn your soap solid-ish again, and translucent (the recipe essentially becomes a mediocre M&P base). Don't use urea, it's nice and hygroscopic but will liberate ammonia in an alkaline environment. There is also a plethora of substances that modify how easily a thick aqueous solution of something builds a film upon drying (polyvinyl alcohol, HEC, hyaluronic acid, plant gums …). I have no overall view, but it might be worth diving into this.
• “Left open” sounds like you have it in an open container/jar to scoop it out with bare hands? We have no clue how you are bottling your cream soap. But packaging can make all of a difference! Have you considered using tubes, or dispensers, or hanging squeeze bottles? The smaller the open surface, the less water can evaporate.

 

[KayMay]

The problem is not the product; the problem is the end user, IMHO. If t'were me, I would put something on the label like "Keep covered when not in use to prevent dehydration" or similar.

Agreed it is the end user (and I do it too). I will put a notice on the label. I haven't sold any yet, as my first batch is only 4 months old, so I can add to the label design

@KayMay
We know very little about the recipe(s) you're using. So it is difficult to provide starting points for modification.
For now, I assume that your cream soap is similar to @Lindy's that @Zany_in_CO has linked above: Dual-lye HP soap (oleic/stearic/lauric FAs) with a generous excess of superfat (post-cook addition of stearic acid).

“Hardness” of an essentially LS recipe can come from several compounds that are present in the soap. Anions: stearate > palmitate > laurate > oleate > PUFA. Cations: FFA > sodium > potassium. So you could shift the recipe to a softer, less hardening-prone composition by going right in these rows; i. e. replace stearic acid by palmitic acid (e. g. replace shea butter by cocoa butter or palm oil), or allocating less lye to the NaOH side, in favour of more KOH.

Yes my recipe is very similar to Lindy's, except I use 1% Kaolin, and 1% powdered sugar, and I blend them into the melted oils then add the lye.

My super cream is 5% stearic and 12.5% glycerin.

I also stir my finished soap once a week, which knocks it back down, like you do to rising bread dough.

My recipe already has a high level of glycerin so I don't really want to add more. I am using a PETP jar, and it does have a lid, i just forget to put it back on. I hadnt thought about a squeeze bottle, but the soap is pretty thick so needs a generous opening

Interestingly, I put some in a small silicone travel tube to take away with me on a work trip, and when I went to use it, 2 days later, it had turned lumpy and semi solid. I think it had must have reacted with the silicone, as there was definitely no leakage. Another investigation needed!

 

[ResolvableOwl]

Hrm. Thanks for clarification. Let me be a bit more nosy, maybe we'll find a way.

Are you aiming to make batches more cooperative that you already have made, or do you want to improve future batches?

What botanical source is your “stearic acid”? I put it in quotation marks, because what is inside the bag indeed depends on who has manufactured it: soy-derived or animal-based products are mostly C18:0 (what chemists call “stearic acid”), while the stuff derived from palm oil actually contains a lot of C16:0 (palmitic acid). Palmitic acid behaves softer in soap and is less prone to solidification.

What is your NaOH/KOH ratio? Less sodium means less solidification.

What about adding water? Of course this might impair thickness, but it's for sure the simplest way to prolong the time that the jar can sit open.


But of course @Zany_in_CO is right that it's the easiest thing to blame the users for their carelessness .

 

[KayMay]

Happy to indulge your nosey-ness.
I am looking to improve future batches. I have not added anything, including water from the initial cook. So far I have 8 batches, and all 8 are behaving slightly differently, even though I used the exact same ingredients. Slightly Different cooking times maybe?
My stearic is palm derived.
I have attached the fatty acid chart.
Stearic is at 60% of total
NOAH is 25% of Soapcalc required amount
KOH is 5 x NOAH
Water is 6 x total lye.
Glycerin is 30% of oil weight plus 12.5% added at super cream stage with 5% stearic
I have found an article that says you can exchange some glycerin for lactic acid and it apparently helps to maintain liquidity.
I might try a small batch, and see how that goes.

 

[ResolvableOwl]

Hmm, okay. Sounds like you're possibly maxed out most of the things already (I have no intuition about the amount of water, though).
Most stearic acid from palm oil is most probably at least 50% palmitic acid, but that really only does matter for bookkeeping (i. e. putting different ingredients into a soap calculator won't salvage your hardening woes). But good to know anyway.

I have next to zero experience with formulating cream soap recipes, so I'm about much guessing as you are. (Don't listen to me, lol!) Your recipe is quite similar to my own trials; the largest distinction (besides you using castor) is that you have more stearic and less oleic acid than me.
It might be worth a try to replace, say, 10% of the stearic acid (or stearate-rich oils like shea butter) by soft oils. Increased oleic (or linoleic if it were up to me ) makes soaps less firm, but slimy-creamy-gooey instead (something usually to be avoided with bar soap, but you might profit from it).
But like said, this is a naïve guess – worth an experiment IMHO but not more.

I have yet to find time to review my own cream soap. The thing I do take time for, right now, is to scoop some out and let it sit for a day or two (or what time scales do you recommend me?) to see if it tends to harden up or not.

 

[KayMay]

Well mine is in a small pot on the shower shelf (open), after a couple of weeks it was the reduced content level that caught my eye first, then realised it was solidifying. I would say it has now reduced by 1/2. It is not totally solid now, more like a dense paste. It seems to have stopped now, so I am guessing it has lost its water weight, it’s been open now for over a month.
The texture of the cream is lovely, I don’t want to change the feel, so I think it is going to be a case of educating the users.
I am following your post regarding your cream soap. Looking forward to hearing your results.

 

[DeeAnna]

"...NOAH is 25% of Soapcalc required amount
KOH is 5 x NOAH..."

I'm puzzled about this method of using KOH at 5 times the NaOH weight. If I'm understanding this correctly, these proportions will result in the soap having a considerable excess of alkali.

Here's the math --

Assume Soapcalc says a recipe needs 100 grams NaOH. Instead, you use 25 grams NaOH and 5 X 25 = 125 grams KOH.

125 grams of KOH is equivalent to how many grams of NaOH? The answer: 125 / 1.403 = 89 g NaOH.

So the total amount of alkali in the soap is 25 + 89 = 114 g alkali expressed as NaOH. Per Soapcalc, the amount should be 100 grams of NaOH instead.

I'm sure the 5% added stearic acid later in the process as supercream will reduce the likelihood the soap will be lye heavy, but a supercream is supposed to remain in the soap as stearic acid, not be converted into stearic soap.

Why not use a calc that is able to calculate the correct amounts of KOH and NaOH for a dual-lye soap? Soapee is one example. Or use the correct stoichiometric relationship (1 gram NaOH = 1.403 g KOH) and calculate the numbers that way?

 

[ResolvableOwl]

@KayMay
I won't wait several weeks, lol! I've scooped out just 7.6 g of each of my two batches into open containers, and will weigh & watch them over the next days. Maybe do some math to estimate how much of it is water.

Don't just use lactic acid as-is, at least not without neutralising it with some extra hydroxide. There is also (already neutral) sodium lactate that might be easier to handle/obtain, but then you would shift your sodium-potassium ratio.
But with the marvelous effect that lactate can have on soap batter smoothness, particularly in HP bar soap, it might be really worth further investigation!
[ETA: Do you happen to have a reference to said article at hand? I'm very curious what they have to say about lactate in cream soap.]

Do you know the purity grade of your KOH?


@DeeAnna
I agree that the recipe is formulated in an unconventional way. But let us for the moment assume that it is alright, and let's see first how much wiggle room the lye purity might give us: 75 g NaOH are equivalent to 105.2 g KOH (pure), so with a realistic purity of 105.2/125 = 84.2% we end up at the stochiometric ratio. A number that is not unheard of. Plus the NaOH purity, plus PCSF stearic acid, plus the extra SAP bonus from tacitly replacing stearic acid by palmitic acid, and the lye balance of this recipe doesn't give me sleepless nights.