Copper and Whipped egg whites

[paulraphael]

Lore and science support using copper bowls for whipping egg whites; copper ions bond to conalbumin molecules, allowing them to form a stronger and more stable foam.

I got a great old copper mixing bowl on ebay years ago, and used to whip all my whites in it. But now that I have an aftermarket balloon-whisk type attachment for my stand mixer, that machine makes life easier even for a single egg white. But the bowl is stainless, and copper replacement bowls or liners cost more than all the meringue in the world.

I've been getting by with using acid (cream of tartar) to stabilize the foam. This works, but not as well, and doesn't provide the kind of insurance against overwhipping as copper.

So lately I've been experimenting. The common warning is to not use both copper and acid, because you'll liberate too many copper ions, resulting in foam that will taste like pennies and that may even be toxic. So I wondered, why not use the solvent power of the acid to get ions from a very small quantity of added copper?

What I've been trying is acidified egg whites (made with the usual quantity of cream of tartar; about 0.4g/egg white)--plus pennies. I just remove tarnish from the pennies and throw them in the mixer's bowl. My starting point is one penny per egg white.

So far there's no taste of copper in the end product, so I know I'm liberating too many ions. But I haven't yet compared to penniless foam, so I don't know if I'm liberating enough to make a difference.

I'll do an experiment soon and report back. Does anyone else want to try this and see if it works?

[chefpeon]

Don't know if this matters, but:

If your Lincoln Memorial penny has a date before 1982, it is made of 95% copper. If the date is 1983 or later, it is made of 97.5% zinc and plated with a thin copper coating.

[paulraphael]

Shouldn't matter at all. The surface is what's in contact with the eggs, and the surface of both kinds is nearly pure copper.