Newbie Question about LS thickness

[fillycate]

Okay, maybe this is a really dumb question (I am about to attempt making goat milk LS for the first time, found a "cold process" method I am interested in trying that involves curing the paste in a jar for a couple weeks, but doesn't scorch the goat milk).

I hear talk of LS being thin and wanting to thicken it. I have even heard talk of combining lyes with some NaOH so the final product is thicker.

But...

I mean...

It starts out as a *paste*. Can't you dilute it less and end up with a thicker soap? What am I missing here?

 

[DeeAnna]

"... It starts out as a *paste*. Can't you dilute it less and end up with a thicker soap? What am I missing here? ..."

The part you're missing is the unusual and unexpected ways that different kinds of soap molecules interact and combine with with water.

Some soaps when diluted with even a small amount of water will not become a thicker pourable gel -- they instead go from a non-pourable paste to a watery liquid over a small range of dilution. Other soaps are also ornery in that they will revert repeatedly back to a non-pourable gel even after lots of water is added. And still others when diluted an appropriate amount will politely form a honey-thick pourable gel.

In large part these differences are all about the fatty acids that make up the soap.

Potassium oleate soap molecules want to make a gel. A potassium oleate soap that is medium high in oleic acid will politely form a thickish pourable liquid with moderate amounts of water. With less water, this same soap will be a non-pourable gel like Jello (gelatin) dessert. This is an ideal type of liquid soap.

A potassium soap that is very high in oleic acid may never make a stable liquid soap --- meaning a mixture that stays a thick yet pourable liquid. It may repeatedly revert to a non-pourable gel as you add more and more water until the water content gets very high. At that point, the soap turns into a water thin liquid and remains that way.

Potassium palmitate and p. stearate soaps also want to make thickish pourable liquids to non-pourable gels.

Potassium myristate and p. laurate soaps want to make thin watery liquids even with very little dilution. This is why coconut oil soap is normally watery -- it contains too much lauric and myristic acid to reliably form a stable pourable gel.

Sodium soaps prefer to be solid soaps, or they want to be thin watery liquids. Sodium soaps are way less inclined to make thickish pourable liquids or non-pourable gels, which is why it's truly not worth the trouble to try to turn a sodium soap into a stable "liquid soap" just by diluting grated bar soap and adding water.

Many soap makers try a blend of sodium hydroxide and potassium hydroxide to get the pourable but thick "gel" product they want, but the likelihood of getting this ideal texture will depend on the relative amounts of the fatty acids involved as well as careful dilution.

There will be some soaps -- especially lauric-myristic soaps -- that will be especially difficult to thicken by using a mixed sodium-potassium lye. Not sayin' it's impossible, but definitely difficult.

 

[fillycate]

Wow, thanks! This is super helpful and fascinating. I had no idea the various fats responded so differently in liquid soaps. I have been thinking all morning about making a hand soap that is olive oil heavy and a dish soap that is mostly or all coconut. Now I know they will respond to dilution very differently...

When I lived in the Philippines for a couple years, they sold dish soap as a paste in plastic tubs. I actually really loved using it that way. I have been wondering if I might enjoy using a dish soap paste in a tub....

I have a lot of experimentation ahead of me.

 

[Zany_in_CO]

Okay, maybe this is a really dumb question (I am about to attempt making goat milk LS for the first time, found a "cold process" method I am interested in trying that involves curing the paste in a jar for a couple weeks, but doesn't scorch the goat milk).

Oooh. Sounds interesting! Please share the method if you don't mind. I've made GM LS for a wholesale customer. In case you don't already know, it finishes with some brown sediment on the bottom. Here's a link to a tutorial to see what I mean.
How to Create Liquid GM Soap

I hear talk of LS being thin and wanting to thicken it.

Properly diluted, this is true. Generally speaking, dilution rates are as follows:
100% coconut oil LS - 40% soap to 60% dilution water.
100% olive oil LS - 15-20% soap to 80-85% dilution water.
All other combos are somewhere in between.

This results in somewhat thin LS but that's just the nature of the beast. You'll be surprised at the nice latherabilty of LS made with the above ratios. That's what I look for. 100% OO can be thickened with a salt solution. As for other combos, I find that using 50% coconut oil plus oil(s) of choice results in a nice viscosity that doesn't need thickening.

You'll know when you've reached the right balance when a skin forms on the surface. Add an ounce or 2 more water, stir to incorporate, and you're there!

I have even heard talk of combining lyes with some NaOH so the final product is thicker.

This is true. I believe @IrishLass 's VERY popular LS recipe is made that way. Worth a look.

But... I mean... It starts out as a *paste*. Can't you dilute it less and end up with a thicker soap? What am I missing here?

In addition to what Top Banana DeeAnna explained above, and my addition, you are absolutely free to dilute your paste to whatever viscosity you like! We all do that! LOL That being said, here's my thinking. The thicker the viscosity the more waste there is when you rinse off and it goes down the drain. At the right balance, your LS rinses off quickly, cleanly, with no soap residue left on the hands. At least, that has been my experience and why I went through a lot of T & E (Trial & Error) to find that balance.

HTH and HAPPY LS-ING!

PS: Good questions! Not dumb at all. Keep it up!

 

[fillycate]

Interesting. So much to tweak and play with here.

Here is the article about making goat milk liquid soap in a cold process:

https://shadyoakandsassafras.com/simple-liquid-goat-milk-soap-recipe/
I want to use a SoapCalc to come up with my own amounts, but I am hoping the actual method used above can work for me to protect the goat milk as much as possible.