Hacker News new | ask | show | jobs
by test001only 1740 days ago
I use stainless steel for a lot of my cooking and grew up in a household without dishwasher. When I got my hand on a dishwasher as an adult and tried out washing the stainless steel utensils in it, I saw that the steel utensils had a coloured pattern left in it - it is similar to the pattern seen when petrol mixes with rain water on the roads. I am not sure if that is safe. Anybody know why this occurs?
2 comments
sokoloff 1740 days ago
I hand wash our stainless pots and get (what I think is) the same. I think it’s a very thin film of something (not likely soap as I can get it without soap).

I use white vinegar to dissolve it about once a month (making me think it’s basic, possibly calcium carbonate). Pour in a cup or so of white vinegar and set the pan to heat. When it’s hot but before it boils, swish it around and then pour it into the next pan. Rinse the first pan in plain water while the vinegar sits in the second. When the first pan is rinsed, pour the vinegar into the third, etc.

Our stainless pans never see the inside of the dishwasher and still get this.

link
exmadscientist 1740 days ago
Do you have hard water? That might do it.

Also, presumably you're fine with vinegar, but for anyone else who prefers less fragrant cleaners, citric acid (usually available as a powder) can almost always be substituted for vinegar with comparable to better results.

link
refurb 1740 days ago
It’s a very fine layer of surface oxidation. Same reason you can get different colors on aluminum depending on how thick the oxide layer is.

Stainless steel is corrosion resistant, not corrosion proof. Dishwashers are actually pretty harsh with high temperatures and high pH detergents.

You can get the same effect by putting a stainless steel spoon in a pot of boiling water.

link
sumtechguy 1740 days ago
On top of that some detergents will leave a bit behind (for various reasons). All of the washers I had, have an extra 'jet dry' compartment. It adds a drop in for the last rinse cycle. Seems to bind to the stuff and clear it up by letting it wash away. So if you are getting spotty glasses after cleaning look into that.
link