I made an ambitious 3! Batches of soap today. By the third batch I ran out of the measuring cups I use to measure and mix my water and lye. So I grabbed this bowl that I thought was stainless steal. I finished making the soap. This one was hot process and went to wash the bowl and noticed a discoloration to the line that the lye water was at. (See pic below -I tried my best to capture it.) Is This an indication it's not stainless steal? I got it at dollarama and usually use it for lip balm. Will this discolor my soap? I don't want a ruined batch - we all know how expensive it Is!
Hi pametan,
The grey/black you are seeing is slight corrosion of the stainless. This happens more often with a lower grade stainless, but can really happen with any grade if the temperature of your liquid lye goes up.
Stainless is pretty resistant to liquid lye at all "hand comfortable" amounts, but once it's too hot to touch the outside of the bowl, you will be getting some amount of etching of the metal. This etching can be made even worse if you are stirring with a metal spoon (because then you are taking off the protective layer of chromium in oxygen-less conditions and then the lye can "eat" at the metal faster).
With the amount of discolouration you are seeing on your bowl, you probably won't see anything in your soap, and you should be able to scrub the bowl back to shiny as well.
If you were to see any discolouration in your soap, it wouldn't be brown, it would be dark grey or black looking, and would form tiny flecks, or super-thin lines, that drop to the bottom of your soap bars if you poured your soap as a liquid. If your soap was hard from the hot process, you may not see this effect at all.
So, to answer your question, no. Your soap will not turn brown from the metal. Looking at your bowl, I doubt there was enough corrosion to colour your soap at all.
