How to stop a lye + oil + water reaction in aluminium container?

I was making soap using a guide for the first time. I accidentally used an aluminium container. It has lye and olive oil in it and was kept on the stove; now it is bubbling and not ceasing (I've turned off the gas).


What should I do to stop it?




**Slowly add vinegar. *DO NOT TURN THE FLAME BACK ON.***


Most likely, the alkali concentration is high enough that you've dissolved away the passivating oxide on the aluminum, and the exposed aluminum metal is reacting with water to form $\ce{Al(OH)4-}$ and hydrogen gas. Adding vinegar should bring the $\mathrm{pH}$ back down into a range where the aluminum can passivate again, stopping the reaction.


The batch of soap is probably already ruined, so I wouldn't worry about that.


In the future, I would recommend using a cast iron or mild steel (*not* stainless) pan for this procedure. Plain iron is remarkable for its resistance to alkali, in my experience.


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