[Sca-cooks] Copper bowl question

[Jeff Gedney]

>    Pewter? You sure? I have one lined with either tin or nickel... It
>    seems unikely to me use a metal as soft as pewter, not to mention its
>    [usual] lead content.

Commercial "Pewter" has not included lead for over 50 years, Adamantius...
Perhaps longer...

I think though, that the "pewter" referred to by the poster is probably whate is
generally called "pot metal" or "white metal", usually an alloy of aluminum,
used for making cheap cast pots from early on in the 1900's, and remains in use
even today. It is notable for being quite brittle, and will crack or break quite
spectacularly.

It used to be used in a lot of home pressure cookers, when the Pressure cooker
"fad" came out in the 60's, with predictable results.

>    >>What is the icky thing given off by copper bowls?!?!?  They are
>    supposedly
>    >>the best thing for whipping egg whites by hand. Is there a chemical
>    >>reaction that results?
>    >
That said, for the original poster, I think that the general consideration with
anything copper is to be sure never to use anything acid in it.
No citrus, tomatoes, wine or vinegar, for example.
You want to be sure to use chemically neutral ingredients in it.


(The following is an imperfect recollection based on chemistry class years ago.
Others such as Avraham would probably give a better discussion...)

As far as egg whites go, IIRC, there is a exchange of electrons with the
protiens in the albumen that cause them to bind together to increase the ability
of the white to "lift". which we can replicate by adding , surprize, a touch of
acid ( tartaric acid in most cases, which we call "cream of tartar" ). You see
acids are characterized by having weakly bound electrons to give off...

But Copper is a very ready chemical partner, ionically speaking, and will react
to acids by Ionically combining with the component of the acid, causing copper
compounds such as copper chloride, or copper iodide, to be put into the food,
and simultaneously depositing the metallic (which could be simple Hydrogen, or
hideously complex Amines) ions into the food as well...

The amount of metal exchange will depend on the acidity of the stuff in the
bowl, and also the time it spends in the bowl.

Brandu


++++++++++++++++++++++++++++++++++++++++++++++

Going back to school is like riding a bike ...

After fumbling with the pedals, getting saddle
sores from a too-small seat, and struggling
uphill, you realize why you got a car in the
first place.

++++++++++++++++++++++++++++++++++++++++++++++