DOS and metal (dreaded orange spots and wire racks) ...

[SaltedFig]

I KNOW that metal triggers DOS.

So when I put the multi-tier wire racking to use, I put down some silicone coated baking paper underneath the soaps first, thinking that with the coating on the wire and the extra protection of the paper, it would be enough of a barrier.

The first peculiar thing I noticed a few weeks ago was that some of the castiles had white spots. I thought that was odd (I haven't seen that happen before, normally they just slowly go white without any sort of spots happening first), but I didn't worry too much.

But ... today, while I was giving the soaps their regular curing turn, I saw for the first time in about a dozen years ... little specks of DOS. And not just on the castiles, but on other soaps that didn't even have olive oil in them.

Eventually I came to the realization that tiny spots on the larger bars matched the pattern of the wires.

A curious notation, which makes this bit of stupidity on my part worth writing about, is that none of the salt bars had DOS, none of the hot processed batches had DOS (3 different recipes) and none the CPOP soaps had DOS. Just the curing, cold-process soaps.

The harsh lesson?

Baking paper (even silicone-coated baking paper) is no barrier to the DOS causing effects of metal on soaps that are still saponifying.

:headbanging:

 

[Susie]

Painful lesson to learn, but thank you for sharing. We all learned something.

 

[penelopejane]

I use old cotton sheet material to line my powder coated wire drawers.
I like the wire drawers because they let the air circulate.
I change the cotton sheet material and wash it regularly (every month or so).
Cross fingers that this continues to work.

I am so sorry to hear you have been visited by the dreaded OS.

 

[SaltedFig]

Copper and soap

I thought I'd share these "before" and "after" photo's of what happens to soap when it touches copper.

Copper powder sprinkled on soap batter (end of March this year).


Discoloration is complete, 9 months later.


Other soaps from the same batch, without copper sprinkles and stored separately, have not developed DOS.

This discolored soap triggers DOS in fully cured soaps (of varying recipes).

Oddly, this bar still smells quite nice (not rancid at all), despite the color.
I'll probably keep this one for another year or so, to observe any further changes.

 

[penelopejane]

I KNOW that metal triggers DOS.

A curious notation, which makes this bit of stupidity on my part worth writing about, is that none of the salt bars had DOS, none of the hot processed batches had DOS (3 different recipes) and none the CPOP soaps had DOS. Just the curing, cold-process soaps.

Baking paper (even silicone-coated baking paper) is no barrier to the DOS causing effects of metal on soaps that are still saponifying.

Are you saying that you don't CPOP castile soap?
If so why is that?

Thanks for sharing the soap with copper on it!

 

[lenarenee]

I thought I'd share these "before" and "after" photo's of what happens to soap when it touches copper.

Copper powder sprinkled on soap batter (end of March this year).
View attachment 26991

Discoloration is complete, 9 months later.
View attachment 26992

Other soaps from the same batch, without copper sprinkles and stored separately, have not developed DOS.

This discolored soap triggers DOS in fully cured soaps (of varying recipes).

Oddly, this bar still smells quite nice (not rancid at all), despite the color.
I'll probably keep this one for another year or so, to observe any further changes.

Are you certain the discoloration is dos instead of discoloration from something else?

 

[SaltedFig]

Are you certain the discoloration is dos instead of discoloration from something else?

The initial reaction (from white soap to green) was rapid, and spread from the copper powder outwards, and into the soap. The change from green to orange was slower, but followed the same progression as the original change to green. The copper I put on the soap caused orange spots in a reaction progression, rather than as a colorant directly, so DOS, in the sense that it's orange, and started as spots and spread.

I expect that a rancid smell will occur over time (as the oxidization progresses further), which is why I will be keeping the soaps (both the orange one and the uncolored versions) for a longer time.

The only thing different between the orange spotted soap (which became fully orange) and the rest of the batch this soap was made from (that did not get orange spots) was the copper.

Is this what you were asking?

 

[psfred]

Instant corrosion of the copper, it's not something I'd put on or in soap for that reason. The bad news is that copper, like any polyvalent metal ion, with greatly accelerate oxidation of the fatty acids.

Use copper colored mica next time, I think!

If you are lucky, the color isn't rancid fats (you would smell them by the time they get that dark I suspect) and is just some copper complex that goes reddish orange. The green was copper salts of fatty acids, which started forming as soon as the copper contacted the soap.

 

[SaltedFig]

Are you saying that you don't CPOP castile soap?
If so why is that?

This castile wasn't gelled.

Pro's
I like the creaminess and opaque look of the ungelled castile. It has a subtly softer/slip feel in use, and seems to be a bit more bubbly.

Con's
The downside is that it remains (even after one year) more reactive than the gelled olive soaps, and the olive scent of the (unscented) soap is slightly more pronounced.

Thanks for sharing the soap with copper on it!

You're welcome! I nearly didn't post it, but I thought I'd better, if I was to finish the story before the end of the year

 

[lenarenee]

My question was rather weak and I was too lazy to ask in a more specific manner. I know that metals can cause dos, but I was trying to be discerning and not automatically blame the discoloration on metals - especially when you didn't detect the smell of rancid oils.

 

[SaltedFig]

Instant corrosion of the copper, it's not something I'd put on or in soap for that reason. The bad news is that copper, like any polyvalent metal ion, with greatly accelerate oxidation of the fatty acids.

Use copper colored mica next time, I think!

If you are lucky, the color isn't rancid fats (you would smell them by the time they get that dark I suspect) and is just some copper complex that goes reddish orange. The green was copper salts of fatty acids, which started forming as soon as the copper contacted the soap.

Thanks psfred. Yes, this copper powder was part of a series of things that shouldn't be put in soap, from my thread Playing with colours that shouldn't be put in soap (some do not belong anywhere near oxidizing agents! :mrgreen.

Still lots of fun, but no, not something to add to a "real" bar of soap!

I still reckon it will get rancid. Surprises me that it isn't already, really. Maybe the charcoal powder helps? Don't know. Probably won't test to find out (unless it niggles me too much and I have to know :twisted.

 

[DeeAnna]

A member who has not posted anything of late - topofmurrayhill -- made an edge beveler, if I remember correctly. TOMH used a piece of copper or brass (an alloy of copper) to make a guide that the soap rubbed against as it was pushed through the beveler. You could see the crisp stripe of DOS on the edges of the soap right where the bar touched guide. Not sure how long it took for the DOS to show up, but it was a good lesson to learn about avoiding anything with copper and similar metals when working with soap.

 

[cmzaha]

I line my chrome racks with grease resistant sandwich wrap and I have never had a problem with my soaps and have been using these racks for a few years now. If I accidentally let a soap hit an uncovered edge I will end up with a spot

 

[scard]

If I were to use aluminum cookie cutters for imbeds, etc.would they also turn orange eventually?:???:

 

[SaltedFig]

If I were to use aluminum cookie cutters for imbeds, etc.would they also turn orange eventually?:???:

Not sure. I've had soap batter react very strongly with aluminium, but have never tried cutting cured soap with an aluminium cutter.

In my lay-person opinion, I would suspect that there would be some reaction (due to the high pH of fresh soap), but I don't think it would be as bad as the copper is. I don't know whether it would be enough to trigger DOS. Hopefully psfred might pop back with some ideas on that.

I would still suggest that you exchange your aluminium cookie cutters for another material, such as plastic or acrylic.

 

[psfred]

Aluminum doesn't change oxidation states as easily as iron or copper, so it would be less likely to promote DOS, but I'd not bet money on that.

What I can assure you is that you aluminum cookie cutters will start to corrode fairly rapidly, even if you wash them quickly. I'd use stainless steel (not tinned carbon steel) or plastic ones.

 

[earlene]

Aluminum Foil deteriorates VERY quickly when soap batter falls onto it. I always keep a pizza pan in the oven covered with heavy duty Aluminium Foil to collects spills of any foods that may be messy when cooking. I place casserole dishes on the pizza pan to prevent spills from getting my oven dirty.

One time when CPOPing, I forgot to put a cardboard liner under the soap mold and some soap batter managed to spill out onto my Aluminum covered pizza pan which I had moved to the rack below. When I opened the oven to check on the soap, I discovered not only had the lye eaten through the aluminum foil, it had begun to eat through the pizza pan as well.

 

[iwannasoap]

I KNOW that metal triggers DOS.

So when I put the multi-tier wire racking to use, I put down some silicone coated baking paper underneath the soaps first, thinking that with the coating on the wire and the extra protection of the paper, it would be enough of a barrier.

The first peculiar thing I noticed a few weeks ago was that some of the castiles had white spots. I thought that was odd (I haven't seen that happen before, normally they just slowly go white without any sort of spots happening first), but I didn't worry too much.

But ... today, while I was giving the soaps their regular curing turn, I saw for the first time in about a dozen years ... little specks of DOS. And not just on the castiles, but on other soaps that didn't even have olive oil in them.

Eventually I came to the realization that tiny spots on the larger bars matched the pattern of the wires.

A curious notation, which makes this bit of stupidity on my part worth writing about, is that none of the salt bars had DOS, none of the hot processed batches had DOS (3 different recipes) and none the CPOP soaps had DOS. Just the curing, cold-process soaps.

The harsh lesson?

Baking paper (even silicone-coated baking paper) is no barrier to the DOS causing effects of metal on soaps that are still saponifying.

:headbanging:

I'm glad to know that. I have a plastic drying rack on top of a metal rack. Would this also apply to that situation and would it also apply to soaps sitting next to each other in that colors are bleeding over to another soap next to it?

 

[GreenDragon]

I also have a wire shelf to store / cure my soaps. I have tried two different liners with great results. My first shelf I lined with cardstock I got from Office Depot. Nice thick white paper that let's the soap breath while curing and protects at the same time. Think it was $10 for 100 sheets.

The other thing I tried with equal success was rolled construction paper you can buy at the hardware store. It's the heavy brown paper you roll out in your house to protect the floor during moves or upgrades. Also very inexpensive at around $15 for 3ftX40ft roll.

Happy soaping!

 

[DeeAnna]

Aluminum doesn't change oxidation states as easily as iron or copper, so it would be less likely to promote DOS, but I'd not bet money on that....

From a research paper I read today, copper tops the list as the Bad Boy of Rancidity followed closely by lead and iron (not saying people would use lead stuff for soaping, just passing info along), then zinc, followed last by tin and aluminum.

Exposing fat to any of these metals increased the rate at which the fat became rancid compared to fat without any metal. That means it's not a good idea to let any metal touch your soap if you want to avoid DOS/rancidity. But aluminum was low on the list of these troublemakers.