What is actually happening at trace?

[Seawolfe]

One of my imaginary friends has also gotten into soaping, and we love to share ideas and bicker.

I have read that it only helps to super fat after HP cooking if you want a single oil as the super fat, that adding super fat oils at trace does nothing.

This makes sense to me because after the HP cook, I know that saponification has occurred, it isn't zappity. I've assumed that when oils and lye reaches trace, it is simply an emulsion, like mayonnaise.

But my friend found this page, which is a handy reference for the properties of oil: http://www.colebrothers.com/soap/oils.html

Among other things, the author states that:

Superfatting soap by decreasing the lye content eliminates the step of adding oil at trace but decreases the control that the soap maker has over what oil is left in the soap. For example, if 5% cocoa butter was added as part of the base oil (say 95% Olive Oil) and the lye amount was calculated for a 5% excess fat level the excess fat in the soap would be made up of a combination of Olive oil and cocoa butter with most of the excess fat being Olive oil. If the same batch was mixed using just Olive Oil at a 1% excess fat level and the cocoa butter was added at the trace stage you would know that the final soap bar contained 1% olive oil and 5% cocoa butter. The cocoa butter would have in this case been unaffected by the lye since it was added after the soap had traced.
...
Trace - The point at which the soap/lye mixture begins to thicken. At this point the solution is about 80-90% saponified and essential oils, superfatting oils, soap colors , additives, etc can be added without their characteristics being changed substantially by the saponification process.

And now I'm all confused. Is trace an emulsion or saponification?

 

[boyago]

That's how I understand the concept of trying to control the SF in CP but I have a really hard time taking their word that 80-90% of SAP has occurred. Batter is still really caustic at pour so I doubt that this number is correct. Though your lye water will a much more dramatic reaction than your batter I think is mostly because of dilution. Also the phase change of the soap is far closer to liquid than solid at pour so there is still allot of intensive reaction going on. That's just my unfounded reasoning though so take it for what it's worth.

 

[The Efficacious Gentleman]

I would strike them 'pon the face with a glove and require them to satisfy honour with a duel!

Caveat - others who know more might well shoot this down like a duck, but there we go

There was another thread about using additives in soap where adding things at trace was spoken about. Personally, I do not think that 80-90% of the lye has reacted with oils to become soap. That is saponification - when lye and oils HAVE BECOME soap. The process is when they ARE becoming soap.

So, by their ideas, at trace you have something that is almost finished soap. You should be able to take it and wash your (gloved!) hands like a liquid soap. But that isn't the case.

Emulsification is when it is all mixed together, after that it thickens and that is trace. Oils and lye are mixed up, but still combining. 80% of the gelling hasn't happened, so the process is clearly far from over!

I do not think that adding oils at trace mean that they spend much less time in with the lye than if they were in the pot with the other oils.

ETA - you cannot selectively SF with CP.

 

[seven]

good explanation TEG, perfectly made sense.

i am highly curious as to where that author was basing his conclusion from. where did the number 80-90% come from? is there a scientific way to calculate it? If so, then he should write it down as well, to back up his findings.

 

[The Efficacious Gentleman]

.......is there a scientific way to calculate it? If so, then he should write it down as well, to back up his findings.

Oh no, we need scientific help on a soaping topic - if only there was a superheroine who could fly in and save us!

 

[DeeAnna]

Okay, where's my cape ... dang, lost the darn thing ...! Oh, well, here I am, sans cape!

I find this statement outrageously inaccurate: "...At this point the solution is about 80-90% saponified and essential oils, superfatting oils, soap colors , additives, etc can be added without their characteristics being changed substantially by the saponification process...."

Just read SMF for a few weeks and you'll find out just how incorrect this is -- colors added at trace do morph, essential oils and fragrance added at trace change their scent and strength, other additives brown or otherwise degrade, and anyone who's been burned by a splash of raw soap batter knows just how "hot" lye can be at or after trace.

Furthermore, if the soap batter was 80-90% saponified at trace, then why does the soap temperature rise so dramatically after that point? To the point of making a "volcano" in some cases? If the chem reaction is largely finished at trace, that much thermal energy should not be created for hours afterwards.

Unlike me, Kevin Dunn (Scientific Soapmaking, Caveman Chemistry) has a chem lab and knows how to use it. He did some experiments to evaluate adding "superfat oils" at trace vs. adding mixing all the oils before adding lye. He reported:

"...[A] soapmaker [may claim] to have superfatted with some particular oil. He may, for example, make soap using 20% coconut oil, 60% palm oil, and 20% olive oil. He will calculate the lye needed for this oil blend and begin to make soap using the calculated lye amount. At trace, however, he adds 5% shea oil and believes that he has “superfatted with shea oil.” He is assuming that the last oil added to the soap is the oil which will remain unsaponified in the finished soap.

"It is this assumption that we set out to test. Let us call it the superfatting hypothesis: Hypothesis: In a superfatted soap some oil remains unsaponified. This unsaponified oil consists mostly of the last oil added, usually at trace....

"The results so far must be treated as preliminary, but I think they are suggestive if not conclusive. In no instance was the superfatting hypothesis supported. For our continuing research we have adopted the kinetic hypothesis: There appears to be no real difference between discounting lye and superfatting.... What this means for the soapmaker is that you may discount or superfat your soap as you please. If you have been trying to incorporate superfatting oils at trace, however, you may have been working harder than you needed to. I would suggest that you thoroughly mix all of your oils before adding the lye...."

Although Dunn's experiments are not 100% proof (one can never conclusively prove something to be true in science), his results are compelling and his conclusions are well supported by his evidence. Dunn's results reinforce my empirical knowledge that saponification is far from done when the batter is at trace. It's my conclusion that adding "superfat" at trace is really not worth the bother.

Read Dunn's articles for yourself: http://cavemanchemistry.com/scisoap/articles.html The one quoted here is "Superfatting and the Lye Discount".

 

[Seawolfe]

Thanks DeeAnna! You da best!

 

[Belinda02]

We see Dunn's conclusions but I'd like to know what and how he tested. My understanding is Saponification is a continuos process. Determining % completion would be difficult unless there was a way to freeze the process. Each batch would have multiply variables and it would be possibly for some soapers to reach 80 to 90% saponification at trace. And who determines trace?

 

[Seawolfe]

Well, it makes sense to me that saponification has not or barely started at trace because:
1) the batter is crazy caustic
2) you still have an exothermic process after trace (gelling), and other things that make colors and scents tricky.
3) its a liquid, not a solid - soap is the salts of the fats - they haven't become those yet (to my tiny mind).

 

[Belinda02]

I don't disagree but not convinced. Th solution is partly liquid because of the presence of warmth, water and a mixture of lye and oil. It moving toward a solid. Crazy caustic is also relative. As humans a zap test doesn't tell us how caustic. How many have taken a zap test at the beginning and compared to the end. Ouch.

I make soap in a large container adding air at a low room temperature. There is no surge in heat until I have stopped stirring, moved my soap into a compact container. Even then temperature is never to hot to touch. It sounds like lye and oil need a small dark private place to make baby soap.

Is an exothermic reaction happening at the start of trace or somewhere toward the end. It sounds most believe it happens all at once after trace has started. To me a trace indicates a chemical reaction has started and continues until complete until all lye and oils have combined. Soapers are keeping batches cool by ice baths and freezers. A surge in heat once stirring has stopped isn't a clear indicator 80 to 90% hasn't already saponified as trace deepens.

 

[grayceworks]

SuperDeeAnna, I ended up reading all 3 articles there again, and while I had read them some time back, at the time they had seemed as gobbledy-gook. NOW, between your excellent explanations, and further experience with some of the things he mentions, it all makes sense.

In the article on superfatting and lye discounts, I do wish he'd mentioned his method for determining how far along the reaction was, but regardless of what level of trace, the results were fascinating in showing which types of fatty acids react quicker with the lye, and which ones remained unsaponified. The fact that ones added well before trace showed up as unsaponified in the finished soap instead of the SF oil used at trace would seem to indicate that the lye was indeed still plenty active at trace if it reacted with the SF oil and left so much of the original oils behind...

That's why I like HP so much lol. The ability to keep my additives intact, because saponification is already done. Like in his water-discount article, he oven-HP's all the soaps for 4hrs at 140F to ensure full and uniform saponification.

But then I went on to read the rest of his article on water discounting and how it affects not only hardness and cure time, but it also shows scientifically the soaps actually becoming milder and less alkaline with each month of cure-time. I wonder just how much less alkaline they would become after a full year as opposed to the 2 months he did? Or if they do just stop on their own -- at what point does that happen?

Even though he did oven HP on them and nearly all of them would have been OK to use right at 1-day, it clearly showed the benefits of various cure times with different oils, including that some oils need more cure time than others. His 50% lye concentration soaps needed 4wks less 'cure' time to reach a level of hardness, moisture content, and mildness that the full-water soaps took at least 8 weeks to reach, and he mentioned that still, all of them showed that they'd become even milder and harder with an even longer cure. I love science!

It also gave me insight on why I have such an issue with CPOP. He had an issue with the olive oil soap and olive oil blend soaps separating and becoming oily on top and lye-heavy on bottom. And this was exacerbated by both pouring before full trace, because of how long the OO was taking to trace, and also by more water.

I would assume this relates to another thread I read -was it Carolyn Z. that mentioned it? - about how full water ends up heating up more during gel than discounted water does. What he described with his OO high-water test sounds just like overheating separation, doesn't it?

I liked how he too had to just toss a whole batch. Makes me feel better. LOL and also how he got impatient waiting on trace on the castile.

As to why this relates to my CPOP issue, well almost all my soaps have a good sized OO content along with the high water content, since I sometimes soap at almost but not quite full water on my CP stuff, thinking that the extra water was giving me more time for swirls and stuff. Which it does, but at the risk of overheating and separating.

I also though it was interesting how the high-water ones stayed slightly more alkaline longer than the discounted ones? He noted it but didn't offer a reason for it? If the lye is more diluted with excess water, is it taking longer to react with the oils? And WHY do all the bars get less alkaline as they lose water? How is the water affecting the reaction between the lye and oils, even after they're supposedly completely saponified?

I'm going to have to experiment now based on the water levels he used and see if maybe I could learn to like CP again lol. I also wonder if RBO would have the same issue? Hmmm.

Also loved his DOS experiments -- looks like I can give up Vit E as an antioxidant and stick with ROE -- I had been going back and forth on those trying to see which was better, but I haven't gotten DOS in anything, so I had no idea if it was those or just good oils, or just the recipe combinations... Now science to the rescue! I'll save my Vit E for leave-on stuff instead of anti-oxidizing my bottles of oil.

And I've totally gone off-topic again, haven't I? Sorry

Sorry SeaWolfe, didn't mean to hijack your thread, as you can see, I love discussing the science parts of it and I'm insanely curious about all the WHY's of things. lol I'll go ahead and leave my other comments though because they may or may not be useful and/or interesting at some point...

I started my thoughts about superfatting and trace above, and I think your conclusions are correct, that the saponification has just barely begun at trace, it's just starting to make enough soap molecules to start thickening up the emulsion.

Which is actually shown fairly effectively in the OO experiment on water discounts in the other article, which is what I had intended to mention above. Because with the more diluted lye, he couldn't get the OO to trace well, and even when he finally got it traced, it did not make soap, it separated again, because the emulsion pretty much broke, like using too much water or not enough emulsifier in a lotion, sortof. There wasn't enough saponification reaction going on to sustain itself and complete the soap, which if it was already 80-90 percent done at trace, should not have happened.

 

[newbie]

I often soap at room temp and once I add my lye water to the oils and combine, well before any trace at all, the batter is already heating. Can it cool off again? Of course. But saponification begins immediately.

Has anyone zap tested at the beginning and at the end? Yes. I can say with authority that soap batter is significantly more caustic than next day set-up soap which is more caustic than two day set-up soap which is more caustic than 3rd or 4th day set-up soap (assuming it is ungelled). I don't have a lab in which I can test, but soap batter is not only zappier than later, it is flat out destructive. I have inadvertently gotten batter in my mouth (I have to soap without gloves because I get batter everywhere without realizing it otherwise and have ended up with it in my mouth) and it will take at least several layers of skin off your mucous membranes in seconds. It is HIGHLY caustic. Does it take off skin when you zap test after a day? No. It is less caustic but still harsh. I have worked with soap every day after a pour with my hands and it is increasingly less hard on your skin as it gets older. Again, not scientific but observation often correlates with lab findings.

I am completely unconvinced that anyone gets 90% saponification with trace, no matter what the oils.

Trace has been defined well enough that even fairly experienced soapers would be able to agree upon when it is reached. Is there a measurement? No. However, even heavily traced batter, that is firm or even seized will take your mucous membranes off.

 

[Seawolfe]

No worries Grayceworks - my friend and I LOVE the whys and hows of things. Thats why our bickering is so fun.

 

[grayceworks]

Oh my... IN the mouth? I've gotten it on my upper lip before, and that was bad enough. Worse than zappiness.

I too had to stop wearing gloves because otherwise I don't realize it's on my hands or wrists and go to rub my face with batter on my gloves. My hands are pretty thick skinned and I don't mind having to reach over to the sink to wash off a bit of batter on my hand, rather than accidentally rubbing an itch on my face or something with batter-splattered gloves. Like I mentioned, upper lip, also forehead, and under the eye. Thank goodness my goggles were on, as I had meant to get an itch at the inside corner of my eye before I realized what I was doing. I used to take my goggles off once the lye mixing and initial mixing to emulsion was done, but now I keep them on until I'm completely done mixing and have washed my hands.

 

[Belinda02]

Newbie, I believe there are tests which can tell us exactly when saponification is taking place and at what pace. Under controlled conditions results could be reproduced. But as soapers our conditions are widely different. Our components are different. I cannot define your results nor u mine.

 

[Tienne]

I used to take my goggles off once the lye mixing and initial mixing to emulsion was done, but now I keep them on until I'm completely done mixing and have washed my hands.

The most risky part of the process for me is when I bang the mould to get the air bubbles out. More than once I've had a little blob of batter go flying.

 

[DeeAnna]

Although I really appreciate Dunn's work with handcrafted soap and respect him as a researcher, I don't always agree with him. Case in point his paper on DOS vs superfat.

The "common wisdom" based on his research paper is that the incidence of DOS (rancidity) in soap is not related to superfat. But if you read his paper carefully, he never specifically observed DOS in his soaps ... only a color change in the first 20 or 30 days after the soap was made.

I wrote this for another thread, but I'll share it here as well:

"...Some people do believe that a higher percentage superfat contributes to the soap becoming rancid, but some pretty good evidence has been presented to show that is not true..."

If you are thinking of Kevin Dunn's research, I am not sure this is entirely accurate. What Dunn's study actually reported was this --

Soap made with a 10% superfat darkened in the first 2 weeks or so after it was made. The same soap recipe, but made with 0% superfat, also darkened, but not as much. Dunn correctly observed that lowering the superfat did not eliminate the color change. He made the assumption that color change in the first 20-30 days is tantamount to the soap getting DOS. By making that assumption, he then concluded that lowering the superfat is not a surefire solution to eliminate DOS.

For the record, Dunn did a related experiment looking at color change in a 100% coconut oil soap and 100% olive oil soap. The CO soap darkened, although not as much as his 100% olive oil soap. Using his logic for superfat, he should have concluded CO is not a surefire solution for eliminating DOS either, but he does not go there in his discussion.

While I respect Dunn's work with handcrafted soap and I do not argue with his experimental findings, I do question his assumption and the "common wisdom" that is arising from quoting him out of context. There is no research that I am aware of that shows a color change in the first 20-30 days is a strong predictor of eventual DOS.

Based on my experience with lye soap, it is my opinion that all soaps darken somewhat during the cure period, unless you add antioxidants and preservatives as Dunn's study reported. But most soaps do not get DOS.

If followup studies do (1) find a correlation between initial color change and the eventual development of DOS and (2) find this correlation is independent of superfat, I will be the first on the "superfat doesn't affect DOS" bandwagon. Until then, I remain skeptical about this "common wisdom". I just don't think the data is there to support this idea.

 

[The Efficacious Gentleman]

Just saw something on another website "Add at a light trace as superfat" GAAAAAAAH!

 

[DeeAnna]

The common wisdom of "add at trace to protect from the lye" and "use vinegar, not water, on lye burns" are my two pet peeves. The second far more than the former, but still. But don't abuse your poor computer, Gent. You'll need it to fight the "soaping myths" good fight with me! Oh, you'll need this cape too....!

And Grayce gets a cape as well -- with that last long post and her contributions to the "superfatting HP" thread, she proved she's appropriately thoughtful, long-winded, and analytical, with excellent math skills to boot.

"...I liked how he too had to just toss a whole batch. Makes me feel better. LOL and also how he got impatient waiting on trace on the castile...."

Yep, I like how he shares his frustrations and failures too; it makes his writing much more enjoyable and personable. When you're a "publish and perish" academic, it's far too easy to lose your sense of humor. That's one of the reasons why I never got a position as a tenure-track university professor -- give me a teaching job at a local small college any day.

 

[seven]

The common wisdom of "add at trace to protect from the lye" and "use vinegar, not water, on lye burns" are my two pet peeves.

mine too!!

i think i'm gonna make a signature with those 2, lol