Dual lye, why?

[Mobjack Bay]

What is the rationale for using NaOH + KOH in a soap? If KOH added to a soap makes it easier to dissolve, which means it makes more lather or bubbles, why not just use more soft oils to get a softer soap? Is adding KOH most useful when you want to stick with a lower percentage of soft oils to reduce the risk of DOS? Or, is it that the quality of the lather in a "hard" soap made with KOH is different from what you get if the recipe includes a higher percentage of soft oils. Or???

 

[Jersey Girl]

What is the rationale for using NaOH + KOH in a soap? If KOH added to a soap makes it easier to dissolve, which means it makes more lather or bubbles, why not just use more soft oils to get a softer soap? Is adding KOH most useful when you want to stick with a lower percentage of soft oils to reduce the risk of DOS? Or, is it that the quality of the lather in a "hard" soap made with KOH is different from what you get if the recipe includes a higher percentage of soft oils. Or???

i found this thread on that might answer the question.
https://www.soapmakingforum.com/threads/dual-lye-castile.59747/

 

[penelopejane]

I tried 5% KOH on all my soap recipes over a long period of time. I use a high percentage of olive in all my soaps. I also tried it in my 100% castile. I use 31-33% lye concentration but in some of the KOH soaps I tried a higher lye concentration.
For me it made my soap soft and it required more drying out between uses.
Everyone who used one of the soaps even if it had been cured for over a year complained that it was softer and didn't last as long.
It was so bad that I eventually threw a whole lot of them away.
I gave up on KOH and have notes - "don't use it again in CP soap".

I don't get slime with my castile as I think we have different OO in Oz than you do in the US. That maybe that is the difference? I just don't know.

But this is just my opinion. Every thread on this forum says it is wonderful. I guess, like absolutely every thing soapy youwill just have to try it yourself.

 

[Mobjack Bay]

I guess I should have done another round of reading before I asked the questions. Thanks for the link @Jersey Girl! i think I may have read some of that thread in the past, but most of it didn't stick. I wasn't thinking in terms of high oleic soap, but was intrigued by the idea of using KOH to reduce oleic slime as discussed in that thread. @penelopejane - then I came back and read your comments. I don't want to soften up any of my existing recipes. Actually, I'm usually struggling to get the stearic and palmitic as high as I would like (in a non-Bastile type recipe) because I also like the silkiness of a recipe that is high in soft oils (and with linoleic at about 13-15%).

 

[Rsapienza]

I guess I should have done another round of reading before I asked the questions. Thanks for the link @Jersey Girl! i think I may have read some of that thread in the past, but most of it didn't stick. I wasn't thinking in terms of high oleic soap, but was intrigued by the idea of using KOH to reduce oleic slime as discussed in that thread. @penelopejane - then I came back and read your comments. I don't want to soften up any of my existing recipes. Actually, I'm usually struggling to get the stearic and palmitic as high as I would like (in a non-Bastile type recipe) because I also like the silkiness of a recipe that is high in soft oils (and with linoleic at about 13-15%).

I have made quite a few recipes with the dual lye method (KOH @ 5%. I did not notice any softness to them at all, however, I believe in most of them I used vinegar as my liquid. I have not experienced a huge difference, but sometimes I think I'm not observant enough. Nothing jumped out at me. I plan to try with Castile. That will be the true test.

 

[SeaSuds]

I use up to 28% soy wax in my soap with low coconut oil and no butters so I add 5% KOH to use against the higher stearic value. I find it adds thickness and creaminess to the lather and in my mind it feels more gentle. My bars are hard and I need to remember to stamp them within 2 days of unmoulding.

 

[szaza]

I have one recipe without coconut oil where I use dual lye to have a bit of lather. I made it before without dual lye and remember thinking the dual lye made a (positive) difference in lather, but the recipe has been tweaked since then and maybe I should try with only NaOH again to see the difference. I feel the dual lye brings some harshness to the soap (or maybe it's the high olive, I recently noticed my skin doesn't care much for olive).
The soap has good longevity with the other ingredients being beeswax, shea and RBO, though I wouldn't be able to say how it compares to the same recipe without KOH.

 

[amd]

What is the rationale for using NaOH + KOH in a soap?

Because you bought KOH thinking you were going to make liquid soap and after making a batch or two you realized it was more work than you were willing to do and now you need to use up that KOH.

 

[cmzaha]

I use 5% in all my soaps. My base recipes are either high tallow/lard combination, higher on the tallow, or high palm some with shea some without. All are made with vinegar at 50% water replacement or once in a while 100% replacement. I have never noticed a difference in softness with 5%. It did help kick up the lather, and with Sorbitol my soaps will now lather when un-molded in less than 12 hrs.
ETA: My Tallow/Lard Recipe contains an aver. 19% Palmitic, 12% Stearic, and 38% Oleic. My Vegan Recipe: 23% Palmitic, 8% Stearic, and 44% Oleic. Both have good longevity

 

[Mobjack Bay]

@amd yep, I've been contemplating liquid soap for about 9 months and it hasn't happened yet...

thanks everyone! I think I'm going to try two batches of a high tallow recipe, one with and one w/o 5% KOH. I will probably keep the CO on the low side (15%), and add RBO to get the linoleic to 15%.

@SoapySuds I don't think the soy wax I have is especially high in stearic. The calculations I did some time ago imdicate it is comparable to lard, tallow and palm. It makes a very nice bar of soap when I use it at 25-30% of my recipe, which also includes some shea butter and RBO.

 

[IrishLass]

I use 80% KOH ......in my hubby's shave soap/croap. If you're looking to use some of that KOH up, a shave soap/croap will definitely help put it to good use..... besides using it in liquid soap.


IrishLass

 

[Mobjack Bay]

I use 80% KOH ......in my hubby's shave soap/croap. If you're looking to use some of that KOH up, a shave soap/croap will definitely help put it to good use..... besides using it in liquid soap.


IrishLass

Good to know! My son has been asking me to make shaving soap. I have a long way to go because I have no idea what "croap" is or means!

 

[IrishLass]

Good to know! My son has been asking me to make shaving soap. I have a long way to go because I have no idea what "croap" is or means!

Don't feel too bad.....I had absolutely no idea either until a few years ago. lol It's a made-up word that many wet-shavers use in order to describe a cross between a shaving cream and a hard shaving soap:

Basically, if it's too hard to be dispensed from a squeeze tube, yet is soft enough to dent it when pressed with your finger, it's a croap.

Based on those parameters, I consider the shave soap I make for my hubby with 80% KOH and 20% NaOH to be a croap. It's definitely not anywhere as soft as a cream, but I can dent it easily with my finger. When young, it's a lot like softened clay in that that you can easily mold into whatever shape you desire, and it will hold that shape, unless you decide to re-shape it. I really love the consistency because I can press them form-fittingly into my hubby's shave mug. As more and more months go by, though, the harder it is to shape it/press it, but if you use enough muscle power, it can still be done, unlike with a regular 100% NaOH bar.


IrishLass

 

[Ladka]

USER=19465]@amd[/USER] yep, I've been contemplating liquid soap for about 9 months and it hasn't happened yet...

Me too - bought a 1 kg container of KOH that is still in the waiting room 🕸[

 

[RacerSpuffy]

Because you bought KOH thinking you were going to make liquid soap and after making a batch or two you realized it was more work than you were willing to do and now you need to use up that KOH.

Yes. That is EXACTLY why I'm going to be doing some dual lye soaps. I bought my KOH over a year ago (still sealed) before I really read what goes into making liquid soaps.