Teach Soap

A few days ago I made a sample batch (500g) to test a sample fragrance from I.F.F., watermelon & kiwi. (Which is rather nice.)
I used exactly the same recipe as usual but decided for some stupid reason to put the FO in at light trace. (This usually messes things up for me.)
Sure enough, the following morning I found a small pool of oil on top, and the bars (this is a divided mould) came out covered in oil.

So, naturally I thought 'ruined batch' and was planning to throw it away, but I rashly decided to tongue test it . . . and it did not zap at all.
I cleaned the surplus oil off, made a pretty strong soap solution from the soap, and pH tested with three different strips including the most accurate (M&N). The pH was 8

I've been wondering what happened. My hypothesis is this:

That the FO's DO saponify, DO take up part of the lye. Just because manufacturers don't supply SAP values doesn't mean an FO doesn't saponify. Surely the FO must saponify, because if it didn't, it would be floating around as 'loose oil' later on.

My question is this: Has anyone actually run a sap test on FO's? Any data on this?
If not, if there's no data, I am considering doing a sap test on one of the FO's. I've got 99% methyl alcohol here and high-spec KOH, so I can make the methoxide, and my scales are accurate to 0.1g, so I should be able to do the experiment. I'll titrate against 10% HCl using methyl red. Maybe I will add a couple of drops of amphoteric surfactant to speed things up.

Comments invited!

Superfat oils don't go through saponification and they don't "float around as loose oil" either. If the FO is mixed in properly it should be a near homogeneous mixture within the crystalline structure of the saponified sodium-oil mixture.

Being a fruit scent I suspect your soap overheated and the oily substance was either secreted FO or glycerin (which seems to adhere to some of the FO molecules and is thus scented). I've had this happen.

_________________
~~Heather~~
Mad [soaping] Scientist

I expected that I might have a heat problem so I used the full amount of water (soapcalc) rather than discounting, and I did not cover the mould, but you're right, it did get pretty warm. Hadn't thought about the glycerin. A lot of the excess was reabsorbed; the pool disappeared by morning leaving everything feeling very oily. I can see myself having to put certain fragrances in the freezer for a while.
I think I will do a test just to satisfy myself. News in due course . . .

Yep, sounds the same as my overheat. It took a few days for all of the liquid to re-absorb, but it did, and the soap is super nice now!

_________________
~~Heather~~
Mad [soaping] Scientist

Sounds more to me like your fragrance didn't incorporate properly and wasn't mixed in enough. The smaller the batch, the more chance for error. It has been my understanding that fragrance oils do not have a SAP value. If they did, every soap calc that's out there would have it. Since not every fragrance oils is made with the same ingredients or constituents, that would make it virtually impossible.

_________________
Irena
Closed minds are like faulty parachutes; they refuse to open.

Is it possible you had a partial seperation of your batch soft oils? When you cut this will it zap on the inside of the bar? Curious.

_________________

~bytheSEAsoap~ Mella bythesea, bythesea, bythebeautiful sea

海の皂

Some fragrance oils will accelerate trace to the point that they are not suitable for cold process soaps. They work better in hot process. Is your fragrance specifically soap safe? Not all of them are. Some are safe for bath & body products or skin safe, but will not work in soap.

_________________
Irena
Closed minds are like faulty parachutes; they refuse to open.

Depending which FO from BB that you use, I would try adding and mixing the scent directly to your cooled off oils instead of at trace. I do this 99% of the time. The only difference is that my batches are much bigger.

_________________
Irena
Closed minds are like faulty parachutes; they refuse to open.

_________________
~~Heather~~
Mad [soaping] Scientist

Busy with the tests on the FO at the moment. Really really difficult - it would be OK if I were doing a sap test on soap oils, but obviously I don't want to be wasting a ton of FO so the quantities are small. I had to make a stirrer from a stainless dental tool and use the high speed electric drill, instead of a stick blender! The first test indicated that the FO had used some of the lye, but I am repeating the experiment in case I made an error.

OK here is what I got:

Indicator: methyl orange, verified with M&N test strips.

1. Blank test (KOH vs HCL)
3g solid KOH, high purity catalyst spec. dissolved in distilled water.
titrated to neutral with 25% HCl, mass of HCl solution required: 8.3g

2. Sap test:
3g KOH, plus 1.4g of BB's blackberry fragrance.
stirred with high speed paddle for 10 min. at 60C approx., foam-forming after a couple of minutes.
Mass of HCl solution required: 7.3g

Difference: 1g.

I'll do the math later when I get some brain cells working, unless some kind soul wants to do the stoichiometry for me and calculate the sap value.
My measurement accuracy is +/- 0.1 g.

My conclusion is that the FO does have a sap value, but that it is small, and that bearing in mind the small percentages of FO we use, it doesn't materially affect the process. Having said that, it still leaves the question of why it accelerates the reaction.

Comments most welcome.

Any of the possible components in the fragrance can accelerate trace. There is no truly way to know as fragrance formulas are secretly guarded. That's why I go to BrambleBerry's web site because I know if I buy an FO from them, it has been tested in cold process soaps.

_________________
Irena
Closed minds are like faulty parachutes; they refuse to open.