Does boiling eggs corrode a saucepan

April 8, 2005 2:39 PM

Does boiling eggs cause a saucepan to corrode over time?

My mother-in-law seems to think so and has one designated saucepan that she has used to boil eggs in for the past 20 years. To support her argument, she showed me the pan which, admitedly, does look pretty bad but I think that's just because it's 20 years old.

Is there something in an eggshell that is corrosive to pans?

posted by gfrobe to Food & Drink (6 answers total)

I don't know the definitive answer to this, but I too have a pot where we do most of our "egg boiling", and it seems to have lost its anodized aluminum coating below the water-line. Our pot is probably only 10 years old, with the "extreme egg boiling" only happening in the past 3-4 years.

Maybe it's just a coincidence, but I think your mother-in-law is on to something.
posted by jimmereeno at 2:46 PM on April 8, 2005

i thought eggshells were mostly calcium. isn't calcium basic, not acidic?

perhaps it's calcium buildup.
posted by littlegirlblue at 3:10 PM on April 8, 2005

Eggs are full of free sulphur. Sulphur, metal and heat creates a coating of iron or aluminum sulphide.
posted by Mayor Curley at 3:21 PM on April 8, 2005

oooh. courtesy of mayor curley's info, google turned up this, which includes:

Non-coated aluminum, however, has a bad habit of reacting to certain foods. For instance, the hydrogen sulfide developed while cooking eggs will cause an unprotected aluminum surface to develop a variety of aluminum oxide and hydroxide complexes. These complexes show themselves as grey or black stains on the surface of the pan and will often cause light colored foods to become noticeably stained. The same staining will also develop when cooking with hard water or high-alkali foods such as potatoes. High acid foods, like tomato sauce, will remove some of this stain and change the color of the sauce.

give that man a peanut cookie! ;o)
posted by andrew cooke at 4:12 PM on April 8, 2005

Boiling a solution of cream of tartar (or vinegar, if you don't mind the house having a nice pickled aroma...) is also effective for making stained aluminum look shiny new again.
posted by nakedcodemonkey at 5:24 PM on April 8, 2005

Cream of tartar does a nice job, but expensive (or used to be anyway) and the pot gets dingy next time you use it.
IIRC, aluminum is highly reactive, and the reason it doesn't oxidize is because it already has, just to a very shallow level and very quickly.
Most people just keep a small pan for boiled eggs and don't talk about it. The sulphides are black, but don't hurt anything with the eggs.
At one time, there was a theory that aluminum caused Alzheimer's, based on the finding of extra aluminum in some brain places, and a lot of people refused to use them, but I think that theory has largely been discredited by now.
posted by unrepentanthippie at 9:47 AM on April 9, 2005