How test soap for FFA (Free Fatty Acids)?

[vas.tzor]

"After each batch is complete, we carefully test the sample to ensure that the batch has no FFA (Free Fatty Acids), and that there is no free lye (FA – Free Alkali). This is done by an acid-base titration method, where neutralisation is indicated by Phenolphthalein."

OK, so the above soap producer tests each batch for FFA and FA. I would like to do the same. I know how to perform the latter test thanks to Kevin M.Dunn 's awesome Book, Scientific Soapmaking. However as for the former test I am not too sure as I have no chemistry background. There is a section on pages 260 -63 in the book which explains how to titrate for Acid Value or FFA however the test is performed on an oil sample and not on an actual sample taken from a batch of finished soap. So my question is can the Acid Value (FFA) test be performed on a sample extracted from a batch of soap which is neutral as per the FA test?

I do know we can test a batch of soap for any unsaponified oil(s) or FFA by extracting a sample, diluting it in water and observing if turns cloudy or not, however I prefer a more quantitative approach. Hope I am making sense to someone out there.

 

[The Efficacious Gentleman]

Not sure that this a beginner subject!

It's not something I personally do (I also don't do a tritation test for excess lye, for that matter) because I am not aiming for an exact 0% superfat and 0% lye discount. A bit of excess oil is not an issue for most people, or specifically their bathroom plumbing, and unless you are testing your lye purity moments before you make a batch of soap, you are not going to be able to get it so spot on that you won't have either excess oil or excess lye.

 

[vas.tzor]

Thank you for your reply. Not what I was looking for - nevertheless much appreciated.

 

[AliOop]

Wish I could offer some assistance, but mostly I'm curious as to why you want to do this. The language you quoted sounds like marketing hype. What benefit is gained by confirming that there is no FFA in the soap?

Of course we don't want FA (excess lye) in our soap. Thus, while I personally wouldn't spend any time or money on this, I can understand why someone might want to be extra cautious and test for that.

In contrast, most people do want FFA, aka super fat, in their handcrafted soap. It's part of what makes the soap less drying to their skin. And unlike FA, FFA certainly doesn't present any dangers to the user. Quite the opposite: it protects the user from potential FA that might otherwise have been present.

I also agree with @The Efficacious Gentleman's point, above, that it is unlikely that you will achieve the perfect balance of soap with zero excess FFA and zero excess FA. If there is no benefit to achieving that, why attempt it?

Thanks for satisfying my curious mind.

 

[vas.tzor]

I am not trying to achieve the perfect balance, just trying to achieve maximum shelf life. Free fatty Acids in the finished product cause premature rancidity.

 

[AliOop]

Thanks for explaining. FFA can cause premature rancidity. However, I have non-rancid bars of soap that are almost 5 years old, and were made with 10% super-fat. In almost eight years of soaping, the only bars I've ever had with rancidity are the ones I made with rancid oils (on purpose, to see what would happen).

Avoiding rancidity is best controlled through your recipe, process, oils, and storage methods -- not by eliminating every bit of FFA. If you keep your super-fat at 5% or under, choose oils that don't go bad quickly, and follow proper manufacturing and storage processes, rancidity is very unlikely.

For those reasons, in my opinion advertising soap that is free of FFA is just that - advertising. But hey, if you enjoy the science part of things, then that could be a fun reason for experimenting with this, too.

 

[vas.tzor]

Thank you for your insight. Please understand FFA and Fatty Acids bound to glycerol ("super-fat") are different.

 

[AliOop]

Ahh thank you for clarifying. I thought they were the same. I’m still wondering why I’ve never heard of this, or had a problem with rancid soap.

How do FFAs occur? And do they always cause rancidity when they do occur?

 

[GemstonePony]

Ahh thank you for clarifying. I thought they were the same. I’m still wondering why I’ve never heard of this, or had a problem with rancid soap.

How do FFAs occur? And do they always cause rancidity when they do occur?

Brief Google search simplified version:
Free Fatty Acids form when water reacts with triglycerides, resulting in damaged triglycerides and easier oxidization for those molecules.

Generally, organic substances in uncontrolled environments break down and rot eventually, FFAs would break down faster and rot faster.
Brief Google search also indicates accurate testing for FFAs generally requires chemical solvents and lab equipment, but I would have had to pay to read the rest of the article, and I'm just not that invested in soap immortality.

Edited to add: since FFAs saponify more quickly, most new soaps should have low/no FFAs. That number will climb again, and factors such as storage conditions and contaminants within the bar will impact how quickly the bar breaks down and how fast organisms move in to take advantage and speed the process up.

 

[Megan]

So, free fatty acids are present in the oils that you are using to make your soap, there should be less free fatty acids in fresh, refined oils. There are (supposed to be) standards for the amount of FFA present. These FFA should be the first to saponify, because it is energetically favorable.

As far as testing in a finished soap, I don't believe it's necessary as well...and even with a chemistry background, I have no idea if you could do this in your home setting. I suppose you could use chromatography/mass spectrometry methods in the research setting, but this is most likely cost prohibitive.

Here's the thing as well, you are saying fatty acids bound to glycerol are different, and yes that is true...but you do realize that these will hydrolyze over time to create free fatty acids, so knowing the FFA content right after making isn't exactly going to be an indicator of whether your soap will go rancid or not.

 

[vas.tzor]

I believe you brought up a very important point with regards to the use of fresh and refined oils. Last year I purchased some olive groves in Southern Greece to to enjoy the benefits of EVO first hand. The oil produced is cloudy and not refined. Just 2-3 weeks after production of what starts off as fantastic smelling soap with a beautiful emerald green color develops the most horrible pungent odor. It breaks my heart. Hmm....... I think I may need to let the oil settle for a few months and clear this time. Anyway much thanks to you guys and gals for answering my initial question.

 

[GemstonePony]

I believe you brought up a very important point with regards to the use of fresh and refined oils. Last year I purchased some olive groves in Southern Greece to to enjoy the benefits of EVO first hand. The oil produced is cloudy and not refined. Just 2-3 weeks after production of what starts off as fantastic smelling soap with a beautiful emerald green color develops the most horrible pungent odor. It breaks my heart. Hmm....... I think I may need to let the oil settle for a few months and clear this time. Anyway much thanks to you guys and gals for answering my initial question.

I'm sure the answers we have weren't what you wanted to hear, but for what it's worth, it's recommended to leave the first pressed stuff for salad dressing and topical uses, as the excess nutrients it contains often hasten rancidity. It's recommended to use later pressings or even pomace for soap.
Here's an article on rancidity prevention I found extremely helpful:
https://classicbells.com/soap/rancidity.aspShe has a ton of other useful articles too, if you're hankering for light reading:
https://classicbells.com/soap/soapyStuff.asp

 

[AliOop]

I believe you brought up a very important point with regards to the use of fresh and refined oils. Last year I purchased some olive groves in Southern Greece to to enjoy the benefits of EVO first hand. The oil produced is cloudy and not refined. Just 2-3 weeks after production of what starts off as fantastic smelling soap with a beautiful emerald green color develops the most horrible pungent odor. It breaks my heart. Hmm....... I think I may need to let the oil settle for a few months and clear this time. Anyway much thanks to you guys and gals for answering my initial question.

Oh goodness, what a disappointment! I agree that EVO is wasted in soap - save it for salad dressings and other culinary delights. Light OO or pomace OO is best for soap.

Two to three weeks is a very short time for soap to become rancid. I assume you were storing them properly: no sunlight, no contact with metal, good air circulation, etc.? And contact only with stainless metal (or none at all) when manufacturing the soap? And distilled water for dissolving the lye?

 

[szaza]

I'm sorry your soap got DOS so quickly.. That's a real bummer!
Some people on here use (store bought) EVOO without problems, but yours sounds more unrefined than what is generally available in stores.
I'd double check to exclude any other possible source of rancidity like @AliOop suggests and if that's all clear, I'd suggest testing a small batch with some rosemary oleoresin added to the oils to see if that helps enough to prevent DOS in the future.
You could also make a small batch of soap with filtered oil to see if it makes a difference.