I mistakenly used aluminum foil...

[David Eisnor]

I made my first batch of soap, I was so careful to follow the recipe exactly as it was shown!! I did not have any parchment paper, so I lined my mold with aluminum foil, and then noticed my soap starting to bubble, and quickly realized that I had done something wrong. I took out the aluminum foil, but want to know if my soap is ruined, or can I salvage it. Please help me. Thanks!

 

[earlene]

Well, your aluminum foil is ruined, that's for sure. Lye eats right through aluminum if left to it's own devices. Your soap could possibly develop DOS on the surfaces that touched the aluminium.

However, since you say you removed the foil, I am wondering how did you do that without disturbing all of the soap? If you had to first remove the soap into another vessel so you could remove the foil, OR if you simple tugged away at the foil and pulled it out from under the soap like one of those pull-the-tablecloth-off-the-table magic tricks, then I'd say you may truly have introduced more metal contaminant points into the rest of the soap. That would make it even more prone to DOS in more areas within the soap. Or maybe you didn't notice until the soap was already set up and firm (how many hours later?)

If it's only on the surface, perhaps you can cut the outer edges off after the soap is ready for unmolding and firm enough to cut. That may prevent DOS formation on the remaining surfaces. But if aluminum was introduced into the interior of the soap (by remixing, etc.) then I don't think there is a remedy that will prevent the likelihood of DOS development.

 

[David Eisnor]

Thank you. Just to clarify, DOS is Dreaded Orange Spots? Harmful, or just not pleasing to look at? I pulled it out, then stirred to make sure that I got any bits out... Basically did everything I should not have done... Can I use it myself, or should I throw it out?

 

[earlene]

Yes, Dreaded Orange Spots. Not just ugly, but eventually they can turn the excess oils in the soap (if you have a high superfat, for example) into a horrific smelling rancid orange blob of soap. In the early stages, it's fine to use. If it's minor little spots, sometimes you can just cut them out if you want and then the soap looks better again. But if you leave this soap to cure and it start getting large speckled orange spots, like orange measles, then I'd say it's doomed.

So I would wait and see how it looks, checking on them every few days. If it's still good in 4 weeks, you could probably just sue them, depending on if your recipe cures in 4 weeks or needs a longer cure. But I would advise against giving them to anyone else. The possibility for DOS is just too high.

Oh, to answer your question: Harmful? Not unless you eat it, I think. Or maybe if you have some sort of skin disorder that makes your skin more susceptible to contaminants.

 

[David Eisnor]

Thank you very much for taking the time to let me know!! Next time I know better!!

 

[SoapAddict415]

Congratulations on your first batch!

 

[DeeAnna]

The bubbling was hydrogen gas. It disperses quickly in the open air, so you probably weren't in any great danger ... but if you put the soap in a gas oven to stay warm while saponifying and there was enough hydrogen in the oven when the burners turned on, things might possibly get exciting. You were fortunate!

Soap and metals do not get along very well, but soap is the least offended by contact with aluminum according to what I've learned recently. After the soap is saponified, that is. I'd follow Earlene's advice to remove all visible specks and maybe some of the outside "rind" of the soap loaf, just for insurance.

 

[SaltedFig]

You would have made some sodium aluminate (a caustic solid) and nitrogen (gas), I have no idea in what quantity. In itself it's dangerous for skin, but so is sodium hydroxide. Being highly caustic, the sodium aluminate should react with your fatty acids (your oils). How that will all end up I don't know.

Personally, I vote for chalking it up to experience and doing it again, but if DeeAnna is advising to pick the bits out and take the rind off and try it, then I would trust that, as DeeAnna is the resident chemistry expert and knows her chemistry stuff!

I suspect that your superfat will be out (not as you designed it) if you keep it.

(I don't think you will get DOS from aluminium. In general, DOS is an indication that your fats have become rancid. There's usually an accompanying dissagreable smell, which gets worse over time and then settles to a musty oldness).

 

[DeeAnna]

This is the reaction between aluminum metal (Al) and sodium hydroxide (NaOH) in the presence of water (H2O) to form sodium aluminate NaAl(OH)4 and hydrogen gas (H2) --

2Al + 2NaOH + 6H2O → 2NaAl(OH)4 + 3H2

There are some good Youtube videos that show the reaction. Although you already know what it looks like, David!

Oxidation and rancidity of fats and soap are accelerated by the presence of metals. Copper and iron are two of the biggies. Aluminum is down the list a ways, but even aluminum has an effect on the rates of oxidation and rancidity. Slight, tis true, but not zero.

 

[SaltedFig]

Thanks for the balanced equation DeeAnna

My curiosity on how it would all end up was after the first reaction, and into what happens to the Sodium Aluminate in the active lye/batter after that ... that's the equation I'm not sure of (where it all ends up).

David, I tossed my one and only batch that reacted with aluminium, and now I'm curious as to whether I did this needlessly!