Mica causing DOS?

[KiwiMoose]

I’ve had two cases of DOS in the past year and was struggling to find a common element- until today. The two that got DOS last year were Lavender and BRV. I tossed out what was left of both. I decided to make my next batch of Lavender soap with Lavender FO only, since I suspected the EO caused the DOS. I did use a little Rose Geranium and Patchouli to help anchor the FO.
Just 5 weeks into cure I notice the FO is already faint, and some oil seeping from the dark purple part of the soap. I think it’s going to turn rancid. This same dark purple was used in the previous Lavender and BRV soaps.

The leaky oil only appears inside the soap where the dark purple swirls are.
Could it really be the mica causing it?

 

[glendam]

I have always suspected the oxide pigments as DOS inducing (not sure if it is because oxide is in their name already?) so I think it is a possibility. However, I once made two soaps from the same batch, at the same time, and poured in the center same cavity molds. Only difference was the fragrance. The soaps made with a very old floral fragrance turned rancid rather quickly. The others delayed a few months. So essentially they were all going to turn rancid because of the main oils, but using a very old fragrance oil seemed to accelerate the process. So it could be a combination of two factors too.

 

[Mobjack Bay]

The seeping oil sounds strange. I’ve used oxide and ultramarine pigments quite often over the last five years and haven’t had any issues with them causing DOS. Overall, DOS occurrence is essentially random when go back through my archived soaps, and there haven’t been any cases where there was an obvious link to colorants.

 

[paradisi]

Poorly made micas can do that, yes.

 

[DeeAnna]

Some years ago I made a batch with a garden rose theme -- a hanger swirl with white (plain soap), green (colored w french green clay), and pink (colored with pink-colored clay) and scented with a rose FO.

The pink areas eventually turned rancid. And then that rancid orange color gradually bled out of the pink areas into the adjacent not-pink soap. That bleeding was how I finally realized what was happening -- rancid pink soap doesn't look all that different than non-rancid pink soap.

The white and green soap that wasn't adjacent to any pink, the soap stayed fine.

I was puzzled for awhile, since I'd done this particular design before without rancidity issues. This last batch was made with the same FO from the same bottle and the same colorants as I'd used before.

I realized the one key difference was time -- it had been quite some time since I'd used that FO. I think the combination of aged FO and that pink clay was the key.

Needless to say, I haven't been too keen on using that pink clay any more and I discarded the FO.

 

[KiwiMoose]

If it is the mica, it's solely the mica, because I opened a brand new FO bottle for this recent batch. The only common denominator between this recent batch and the two from last year ( both different fragrances) is that mica. The mica ingredients are: Mica, Titanium Dioxide, Iron Oxide, Manganese Violet. I have had it a long time - does it go off?

 

[AliOop]

I have to wonder if it's the Manganese Violet. After all, manganese is a metal, and metal causes DOS, so... ?

 

[paradisi]

If it is the mica, it's solely the mica, because I opened a brand new FO bottle for this recent batch. The only common denominator between this recent batch and the two from last year ( both different fragrances) is that mica. The mica ingredients are: Mica, Titanium Dioxide, Iron Oxide, Manganese Violet. I have had it a long time - does it go off?

No it doesn't. But it might have a contaminant in it. (Source? Keep lids tight? etc.)
Some of the early micas did things like that, it sourced back to bad batches the sellers got from China.

You might contact your supplier and ask if they've had reports of problems with the lot you got from them.

 

[Zing]

Aww, man! That is gorgeous work, hope it doesn't go rancid!

 

[hlee]

So pretty!