Why do some sites and books say you MUST use lye?

[soapbuddy]

You make a form of lye by running water through wood ashes, so my guess would be the burnt plantain skin ashes are also making lye.

That will make potassium hydroxide, but not sodium hydroxide. It's the ashes that make the soap black.

 

[Megan L-T]

Just out of curiousity, what is used to make a detergent? I have a potential customer who swears she buys soap that doesn't have lye in it. I'm trying to tell her it HAS to have potassium or sodium hydroxide (either caustic)........but it would help if I were able to intelligently explain to her that she may be buying a detergent. Also, am I correct in my undertanding that you use potassium hydroxide to make liquid soap and sodium hydroxide to make regular CP bar soap?

 

[soapbuddy]

Just out of curiousity, what is used to make a detergent? I have a potential customer who swears she buys soap that doesn't have lye in it. I'm trying to tell her it HAS to have potassium or sodium hydroxide (either caustic)........but it would help if I were able to intelligently explain to her that she may be buying a detergent. Also, am I correct in my undertanding that you use potassium hydroxide to make liquid soap and sodium hydroxide to make regular CP bar soap?

Detergents have surfactants ie: polyglucose lactylate. They don't have lye.
Yes, potassium hydroxide makes liquid soap and sodium hydroxide makes regular CP soap.

 

[sarawithouth]

Who ever you purchased that soap from lied.

Actually, they "lyed."

 

[dieSpinne]

You make a form of lye by running water through wood ashes, so my guess would be the burnt plantain skin ashes are also making lye.

That will make potassium hydroxide, but not sodium hydroxide. It's the ashes that make the soap black.

if you use saltwater to wash or blend with your plantain ashes, the sodium from the sodium chloride, put in simplest terms, has a stronger ionic attraction to the fatty acid chains in the shea butter and so precipitates the harder form of sodium soap... the potassium remains in solution with the chloride ions.

 

[younglivingmargo]

using lye

do a search on the chemistry of soap for a more detailed explanation, but essentially, soap is the result of reacting fatty acids (oils) with caustic (lye). it does result in some glycerin, but also in sodium (if using NaOH) or potassium (if using KOH) salts of the fatty acids - also known as SOAP.

true soap is made using a caustic (lye). some soapmakers choose not to show this on their labels. our soaps are a mix of water, salts of fatty acids, excess oils, and glycerin, plus whatever else we put in there.

commercial soapmakers (like P&G) make soaps very differently. if they are making real soap (the salts of fatty acids), they typically purchase (or make elsewhere) these salts of fatty acids and they purify them - so they don't have the mix of ingredients unless they choose to put them in there. and they don't typically list the caustic. many times they are not selling "soap" per se, but actually detergent products which - chemically speaking - are another animal altogether. they act the same way soap does - as emulsifiers - but are different. detergents are not soaps and are not produced by mixing lye with oils.

oh, and many commercial soaps are a blend of soap & detergent.

yes - adding lye results in glycerin, AND SOAP. glycerin is not the same as soap.

if you don't want to handle lye, you can purchase pre-made soap or a detergent base. it's called melt & pour and is fun to work with.

GREAT INFO CAREBEAR. THANKS

 

[carebear]

You make a form of lye by running water through wood ashes, so my guess would be the burnt plantain skin ashes are also making lye.

That will make potassium hydroxide, but not sodium hydroxide. It's the ashes that make the soap black.

if you use saltwater to wash or blend with your plantain ashes, the sodium from the sodium chloride, put in simplest terms, has a stronger ionic attraction to the fatty acid chains in the shea butter and so precipitates the harder form of sodium soap... the potassium remains in solution with the chloride ions.

right. you can actually boil your soft (potassium) soap with heavily salted water and the sodium and potassium will switch places and you can scoop harder soap "curds" out of the water. Don't recommend it - it's messy and not efficient at all.

 

[Mom2LilMan]

Regarding the original question, did the soap manufacturer not have to put the lye as an ingredient because it's chemically gone after the reaction has occurred? Or should it have been in the ingredient list?

 

[fiddletree]

I'm a bit fuzzy on American labeling laws (I'm assuming that is where you are), but it is my understanding that as long as it just plain soap and no claims are made, no ingredients have to be listed, but if they list *some* ingredients, they must list them all.

So yes, if they listed oils and water, they should have listed sodium hydroxide. Or even better, they could have listed the sodium salts (plus water and glycerin) that are the result of the chemical reaction to make soap, since there shouldn't be any lye in the finished product.

 

[carebear]

Apparently they can get away with listing the salts of fatty acids (sodium tallowate) instead of tallow + lye. It's entirely inaccurate since not all the tallow is saponified, but that's the rule anyway. Go figure.

 

[fiddletree]

Apparently they can get away with listing the salts of fatty acids (sodium tallowate) instead of tallow + lye. It's entirely inaccurate since not all the tallow is saponified, but that's the rule anyway. Go figure.

It's actually more accurate than it seems, and technically more accurate than fat/oil+lye. The 'sodium whatever-ate' terminology includes sodium salts and remaining fatty acids left after the reaction. Anyhow, we don't know that any of the original fat/oil is left unaltered, since lye eats away at the fatty acids really randomly, even with a fairly large SF.

 

[shella]

i do not know if this is correct. but i have come to understand that dove do not call there product soap because if it has no lye in it. then the product cannot be called soap dove call there product a moisturising bar

 

[melstan775]

Dove lists their ingredients in the INCI manner. Their first ingredient is sodium tallowate. Sodium tallowate is the salt you get from lye and tallow. They basically hide that sodium hydroxide was part of their formula.

 

[NativeSisterSoap]

No. To make soap, you must have a salt (lye). Remember chemistry? If you mix something acid to something alkali in the right proportions you end up with something neutral? Well that's how soap is make. Lye is very alkaline. Oils have fatty acids in them. The alkaline lye mixes with the fatty acids in oils/fats and you have soap with a by-product of glycerin.

 

[Lindy]

Since lye is not present in the completed product it does not have to be listed as long as you are using the INCI names for the oils. No lye = no soap. Most commercial brands are detergent bars so they are not truly soap....

 

[hoegarden]

right. you can actually boil your soft (potassium) soap with heavily salted water and the sodium and potassium will switch places and you can scoop harder soap "curds" out of the water. Don't recommend it - it's messy and not efficient at all.

oh ****.. I am still thinking of using salt water to dissolve my KOH soap that have finish curing. I was thinking that salt water will thicken the mixture. so my liquid soap will not be too liquid... :eh:

 

[Rigneylane]

To Lye or not to Lye!

Some of the confusion on the label may come from the fact that "Lye" is not generally stated on a soap label as an ingredient. I never put it on the label either. One just generally states the fats, oils, and additives. It is ASSUMED that NaOH (sodium hydroxide=lye) was used to make a hard soap, and that KOH -potassium hydroxide-was used to create a liquid soap.

Melt and pour bases do not require lye to work with them because they have already been saponified. They are simply melted and you add whatever you wish. Many melt and pour bases have a glycerine-ingredient base.

You can also buy soap or soap-shreds (soap noodles) on line to rebatch. That also does not need lye. Again, you can add whatever you want during the rebatch.

 

[Scentapy]

One just generally states the fats, oils, and additives. It is ASSUMED that NaOH (sodium hydroxide=lye) was used to make a hard soap, and that KOH -potassium hydroxide-was used to create a liquid soap.

ASSUMED by whom? Soapmakers? Yes. Customers? NEVER ASSUME. I did not know how soap was made before I started researching how to make soap.

I don't know the answer as to whether it needs to be on the label or not... but I just do it. Why wouldn't you just put it on there to be safe? What is the reason for leaving it off?

 

[Genny]

ASSUMED by whom? Soapmakers? Yes. Customers? NEVER ASSUME. I did not know how soap was made before I started researching how to make soap.

I don't know the answer as to whether it needs to be on the label or not... but I just do it. Why wouldn't you just put it on there to be safe? What is the reason for leaving it off?

Because it scares people :roll:
Why does it scare people? Because they don't know the process of soap making.
So you're right Scentapy, never assume.

 

[Mommysoaper]

According to the FDA, you can either list the "starting ingredients" on the label, or the "reaction products" that resulted from the chemical reaction. In order to use the "reaction products" you need to know the amounts of each reacted ingredient, the amount of glycerine created after the rxn, the amounts of remaining unsaponified oils, any remaining unevaporated water or liquid (milk, beer etc), and any fragrance, herbs, clays, colors or other additives. And they need to be listed in descending order of predominance.

I got this info from the book, Soap and Cosmetic Labeling: How to follow the Rules and Regs explained in Plain English by Marie Gale. She states it pretty plainly in her book how soap should be labeled and the circumstances surrounding why soap should be labeled. Unless you take your soap to get tested and get a breakdown of the components and their amounts after the chemical reaction of saponification has occcurred, then it would be a little touch and go to list your ingredients through the "reaction products" method which would allow you to not list lye. But even still, I think any responsible soapmaker using that method would explain the "sodium tallowate" was an end product of using lye with tallow.

Hope this makes sense! I have found marie Gale's book to be very valuable in helping me understand labeling laws. The FDA website is easy to find too. Google it!