Geek Tips

[ngian]

If you have extra fat, you cant react it all and you are looking at:

Excess Fat + Lye =Glycerin, Soap, Fat

Galaxy isn't it possible for the equation to be:

Excess Fat + Lye =Glycerin, Soap, (Glycerin + free Fatty Acids)

meaning that the unsaponified fat could be hydrolysed and thus more glycerin molecules would add to the other glycerin content in the final soap?

 

[DeeAnna]

"...Excess Fat + Lye =Glycerin, Soap, (Glycerin + free Fatty Acids)..."

Okay, Nikos, since you are wanting to take this a step further than the basics, I'm going to put my chem professor hat on and trot out a fuller explanation.

You are making the incorrect assumption that a triglyceride fat is always fully broken down into free fatty acids and glycerin. Lye is strong enough to actually do this full decomposition of the triglycerides. Once the lye is consumed by the saponification reaction, however, then full decomposition of excess triglycerides (aka the superfat) becomes far less likely. The superfat may hydrolyze in the presence of water, warmth and time, but this is going to be a slow and difficult chemical reaction. The triglycerides that do decompose by hydrolysis are more likely to be only partially hydrolyzed into monoglycerides and diglycerides. The tri-, di-, and mono-glycerides in the superfat still act like fats, not like glycerin.

So the bottom line is Galaxy's explanation is accurate enough to explain how the glycerin is made and how much glycerin is produced. Yes, it is a simplification, but it's sufficiently accurate for everyday use.

Newton's Law of Gravity is a similar simplifying assumption. For 99.99% of us, his law is plenty good enough to use to explain how gravity works, even though super-geeky physicists know Newton's Law is a gross simplification.

 

[TeresaT]

Teresa, glycerin is only produced when the NaOH can react with the fats. If you have a positive superfat then you have excess fat. But, for that tip/equation it doesn't matter.

Example:

Fat + Lye = Glycerin and Soap THIS MAKES SENSE TO ME.

If you have extra fat, you cant react it all and you are looking at:
Excess Fat + Lye =Glycerin, Soap, Fat THIS MAKES SENSE TO ME.

If you have extra lye, you are looking at:
Fat + Excess Lye= Glycerin, Soap, Lye. THIS MAKES SENSE TO ME.

Since the calculation is based on lye, if you use a negative super fat (excess lye) you will [artificially increase the amount of glycerin] you would expect using this equation. Fat is not factored into this equation so super fat has no perceived effect on the glycerin content because you're using a fixed lye amount that will react with a fixed amount of fat.

You lost me in the bracketed area. If you have a negative super fat (excess lye) how would you "artificially increase" the glycerin? Isn't the "negative super fat" the same thing as the third statement you have (extra lye)?

So, I think the answer to my question was actually, "Yes." The SF has no part in the equation. As long as I have enough fats to react with the oils to actually make the soap/glycerin.

 

[galaxyMLP]

I'm really sorry I lost you/confused you. Yep, superfat has no effect in this case. Yes,my statements are the same. And it looks like you understand it all but, in case you don't:

Let me try to explain the "fuzzy" area for you a bit better. In this equation NaOHx0.77=glycerin, we aren't looking at what the superfat is and are just basing the glycerin amount on the NaOH amount. This is true for NaOH that does react. In zero superfat and positive superfat cases, that is true. All NaOH reacts. But in cases where we have extra NaOH not all of it can react. That means for that extra amount of NaOH you wont have any amount of glycerin produced. However, your equation (because its only based on the amount of NaOH) would make it look like you're making more glycerin than you actually have.

ngian, I didnt want to go into that lengthy explanation of the hydrolosis. It would have been confusing. I agree with Dee that the hydrolosis would take a long time. Other side reactions could also occur that may or may not produce glycerin. The equation is simply a simplification of what is occurring.

 

[Dahila]

Glycerin calulations:

NaOH it is lye amount x 0.77 = glycerin e.g. 136g x 0.77 = 104.72 g of glycerin

KOH it is lye x 0.55 = glycerin amount

Here is the calculation in use and why from Scott:
1g NaOH gives 0.77g glycerine
1.4g KOH gives 0.77g glycerine
so 1g KOH gives you 0.55g glycerin


Quick explanation - it's the OH part of the alkali (lye) that "makes" glycerin in the saponification reaction - K atom is heavier than Na atom so you need more KOH (weight) than NaOH to provide the same amount of OH

When using NaOH, 1g of oil/fat gives 1 g soap salts
When using KOH, 1g of oil /fat gives 1.4g soap salts

Sorry I think they use different form for glycerin in Europe ; glycerine. Maybe it would be easier for T;to get it. I got it and English is my second language so she will too))

 

[ngian]

... For a castile (100% olive oil) CP soap, I would use a 40% lye concentration to encourage the soap to trace faster

I want to fill in some info and little experience I have on Olive Oil. Lye concentration on castile is very much dependent on the acidity level of the olive oil (amount of free fatty acids). Extra virgin olive oil has an acidity level of <0.8% and lye concentration of 40% would be ok. But if the oil is very old and/or the storage conditions are not very good (exposure to air/heat/light) then the triglycerides breaks off, leaving a diacylglycerol or a monoacylglycerol and thus there are many free fatty acids floating around the oil. These saponify very fast in contact with lye, so using the normal 33% Lye concentration (or even 30% if acidity level is too high), soaping cooler and using whisk instead of a SB are things to take into account.

I think Kevin Dunn describes in his book how someone can measure an oil's acidity. An Olive Oil of high acidity level has a sour taste and has a strong acidic kind of smell.

Okay, Nikos, since you are wanting to take this a step further than the basics, I'm going to put my chem professor hat on and trot out a fuller explanation.

You are making the incorrect assumption that a triglyceride fat is always fully broken down into free fatty acids and glycerin. ...

Thank you for your explanation DeeAnna, and as I was reading that you would put on your chem hat I was afraid of reading some weird chem phrases or an chem-alien language, but for my luck it was an earthy and friendly language

My assumption though was in deed very extraordinary but just wanted to make it more vivid.

ngian, I didnt want to go into that lengthy explanation of the hydrolosis. It would have been confusing. I agree with Dee that the hydrolosis would take a long time. Other side reactions could also occur that may or may not produce glycerin. The equation is simply a simplification of what is occurring.

Galaxy I just wanted to know if in the unsaponified oils part, someone can find free fatty acids and glycerols apart from triglycerides, diacylglycerols, monoacylglycerols by the time of the saponification is finished (no more active lye present). Free fatty acids that were extracted from glycerol molecule by lye but didn't finally saponify. I understand the reason for simplicity but being curious I sometimes want to dig a bit deeper.

So the party - metaphor story with the saponification could be enhanced:

3 girls (fatty acids) go with their mother(glycerols) to a big party hand in hand. Every mother that enters the party, 3 guys (Lye) approach her in order to convince her to release her 3 daughters. So when they finally do, they get a chance to dance and see if the can pair. The rest of the story is very well narrated by DeeAnna:

It's like the fats and lye are having a big party with more fats (girls) than lye (guys) in the house. The guys at the party (the lye molecules) prefer blondes (coconut oil), but there are lots of pretty brunettes and redheads on the dance floor to mix with. These darker haired girls (olive oil, for example) dilute the concentration of blonds. This means the lye guys will find it harder to pair up with a girl with the "right" hair color and easier to pair up with a girl of another hair color (olive oil reacting with lye rather than coconut oil reacting w lye).

Even though some of the lye guys are eventually going to pair up with the blonds they prefer, many will pair up with the brunettes and redheads instead. At the end of the party, the lye guys will have hooked up with a fair number of the darker haired gals by the end of the party. It is likely that at least some girls of each hair color will remain without a partner. Given that this interaction is all about chemistry and probability, it's difficult to predict how many blonds, brunettes, and redheads will be left over.

http://www.soapmakingforum.com//www.pinterest.com/pin/create/extension/

 

[DeeAnna]

"...if in the unsaponified oils part, someone can find free fatty acids..."

Not Galaxy, but here's my thoughts on the matter.

In a freshly made soap, the probability of finding free fatty acids is pretty low, because FFAs react so very easily with lye.

Oil manufacturers use various methods to reduce the acidity (aka FFAs) in their oils to "improve" their edible oils for sale. One method used historically was to add a small amount of an alkali -- NaOH, soda ash, etc. -- to the oil and allow the alkali to saponify the FFAs and then skim the soapy bits off the oil. This method works effectively only because FFAs react much more easily with an alkali than the parent oil.

Getting back to soap ... As time goes on, yes, there is a definite possibility of an increasing amount of FFAs in the soap, because the superfat in the soap gradually decomposes and eventually becomes rancid. This decomposition is not caused by lye -- that is long gone -- but due to some combination of hydrolysis (reaction with water), UV decomposition, and possibly bacterial action.

 

[ngian]

Thank you for your great info! Very interesting method they used in "cleaning" the FFA!

Ok so here is another question that arises. DOS - Dread Orange Spots.

They appear mostly in soap when


- the superfat is more than 5% (the bigger the number the better for DOS),

- when we use oils richer in polyunsaturated FAs as these are more prone to rancidity having 2 & 3 double bonds,

- and when the oils are old as heat, light and oxygen and time, conditions at which oils are going rancid (because of the oxidative process as you also mentioned). This one is true for all soft oils I guess.


The third bullet is true when for example someone makes a castile (100% Olive Oil) with a very old OO (2-3years old). They see more easily DOS in their soaps in contrast with a Castile made with EVOO while everything else is equal.
So is it for the fact that in the superfat area there are triglycerides that are old and tired and can brake up easily to FFAs, or is it moslty monoglycerides and diglycerides that brake up even faster to FFAs and glycerine?

And the orange color is made by FFAs?

You can wear your chem suit also, I'm all ears (eyes) in case you have any info or link on these matters. http://www.soapmakingforum.com//www.pinterest.com/pin/create/extension/

 

[galaxyMLP]

-The orange color is not from the FFA's. Its from them breaking down. The FFA's can break down further and give off ketones or other, "stinky" compounds that are colored. Thats why FFA's can be odorless but rancid oils smell. FFA's arent 100% tied to rancidity. Look at FFA's like stearic acid and palmatic acid. They are very stable. Rancidity usually occurs in high temperature situations or with other stress.

-I'm not quite sure about the olive oil question that you asked. Once the oils begin to break down I do know that they begin to breakdown at a faster rate. I think the real issue with old olive oil (or any oil) is that it is already beginning to go rancid (FFA's are further breaking down). It doenst have to smell bad yet for you to be able to tell that FFA's have started breaking down. You likely have a higher rate of FFA's in old oil and when that is exposed to the high heat/ strong chemical reaction of saponification it is more likely for things to break down further past the FFA state which leads to rancidity/DOS.

-One other thing, yes, its possible to have additional glycerin formed after saponification from triglyceride break up not due to NaOH. But, it is unlikely and will occur more slowly over time if at all. Other forms of breakage can occur (like mono and diglycerides) without forming glycerin. Sometimes, they (indiustry) uses steam to hydrolyze (saponify) oils to create FFA's and glycerin. Thats an example where high heat and water can take the place of NaOH. You are left with no "salts of fatty acids" in that case of course. Only the FFA's themselves.

I hope all of this helps!

 

[DeeAnna]

What Galaxy said -- yep!

 

[ngian]

Thank you very much Galaxy for your explaining, it helps me a lot to understand how oil's quality is degraded

 

[galaxyMLP]

I'm really grateful that my explanation was able to help you!

 

[DeeAnna]

Geek Tip -- Avoid Common Errors for Soap Labels!

Do you know the rules for designing a correct label for US sale? I don't! Marie Gale knows the subject of soap and cosmetic labeling far better than I do, so here is her helpful blog post about errors often made when designing soap labels:

http://www.mariegale.com/five-most-common-labeling-errors/

Did you know there's a difference between a "label" and "labeling"? Briefly, a label is the marking on your product, and labeling is the secondary information in your store, sales booth, or website. Even though a label on a bar of soap may be in compliance for the rules for soap, your labeling can redefine the product as a cosmetic or drug if you make inappropriate claims. You are responsible for both being in compliance with the rules. Marie Gale explains in more detail:

http://www.mariegale.com/label-vs-labeling/

Have trouble finding information on the FDA website? Here is a handy FAQ (frequently asked questions) about FDA rules for soap, cosmetics, and drugs:

http://www.fda.gov/Cosmetics/ResourcesForYou/Industry/ucm388736.htm

 

[Be Love]

Love this thread! Thanks everyone for your 'geek' tips! I wish I had one to contribute! It's amazing how much we can learn from each other. If you ever need a tip on childbirth, I'm your gal! Lol

 

[ngian]

-The orange color is not from the FFA's. Its from them breaking down. The FFA's can break down further and give off ketones or other, "stinky" compounds that are colored. Thats why FFA's can be odorless but rancid oils smell.

Hello galaxyMLP,
So when we have a very old Olive oil that smells already bad and we will try to make soap with it, the ffa that will have broken down further will not saponify and thus there will be more unsaponifiables (ketones or other, "stinky" compounds ) in the final soap?

 

[Susie]

Not galaxy, but I can tell you that rancid oils make stinky soap. I learned this the hard way.

 

[DeeAnna]

One way to reduce the chance of odor in the soap is to wash the fat with water before using it to make soap. The ketones and aldehydes apparently are partially or wholly soluble in water. If you can smell the "off" odor, keep washing until the odor is gone. Multiple washes with a moderate amount of water per wash are going to be more effective than one wash with a lot of water.

Check this thread out, especially post 15 by Grayceworks: http://www.soapmakingforum.com/showpost.php?p=381830

 

[ngian]

Thank you very much DeeAnna for your answer and link. I just added one more page in my soaping book of knowledge!

Susie I understand what you mean because I have used a soap from another soaper, that smells stinky, and I guess this is the reason.

One way to reduce the chance of odor in the soap is to wash the fat with water before using it to make soap. The ketones and aldehydes apparently are partially or wholly soluble in water. If you can smell the "off" odor, keep washing until the odor is gone. Multiple washes with a moderate amount of water per wash are going to be more effective than one wash with a lot of water.

Check this thread out, especially post 15 by Grayceworks: http://www.soapmakingforum.com/showpost.php?p=381830

In the link provided they advise to use boiling salted water in order to clean all the impurities in an old /used oil but I was wondering if the same can be done with a room temperature brine (at least above the oil's melting temperature).

I'm thinking that boiling brine will create more impurities (that will eventually clean them too) as heat is also breaking down further the "healthy" ffa, resulting in even lesser amount of cleaned oil for saponification.

 

[DeeAnna]

Well, try it if that is your concern, but keep in mind when you mix boiling water with room temp oil, the mixture is not going to be anywhere close to boiling. Also bear in mind you're dealing with solubility issues -- chemicals tend to be more soluble at higher temperatures than at lower.

 

[topofmurrayhill]

I'm thinking that boiling brine will create more impurities (that will eventually clean them too) as heat is also breaking down further the "healthy" ffa, resulting in even lesser amount of cleaned oil for saponification.

There might be some additional oxidation. There would be some hydrolysis as well, so additional FFA could be produced. However, the amount of all these substances is decreased, so it seems worthwhile. Even "healthy" FFA is reduced by this process, which could be helpful in making the oil behave better for soaping.

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