Re: Tea and metal

In article <1140203222.074849.290260@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>, Dominic T. <dominictiberio@xxxxxxxxx> wrote
I'm not sure how or where it started (most likely I read it in a book)
but I have always done everything in my power to keep metal from
touching my tea in both storage and brewing. Such as boiling the water
in either an all glass whistler teakettle or in a ceramic coated metal
one. Not using a metal spoon to stir, no metal teaballs, glass tea
canisters... etc.

But a recent need to find storage containers for my tea (my other
thread from today) keeps coming up with tea tins, and canisters made of
metal primarily. Also many tea vendor's keep their tea in metal
canisters, or ship in a foil pouch.

Am I just crazy, or is there some logic to the "no metal" theory?

You're half crazy ;-)

Some metals will react with some combinations of water, air, salts and acids. (Also other metals; dissimilar metals plus water with anything dissolved in it that makes it electrically conductive are a recipe for rapid electrolytic corrosion.) Others don't.

If
metal is OK, which are the best? Stainless,

It's formulated to be non-reactive.

Tin,

A thin plating of tin on steel to prevent it reacting with the contents used to be the basis of "tin" cans. You only get problems if the tin wears away, exposing the base metal and facilitating electrolytic corrosion. I'd guess most "tin" tea containers are this kind of tinplate.

Copper,

Quite reactive.

Silver,

Reacts with sulphur (don't use silver spoons on S-rich eggs.) Apart from that, it's probably not very reactive.

Aluminum?

Paradoxically, so reactive that it's not a problem. Pure Al on exposure to air almost instantly forms a layer of oxide. That's the same substance we meet in other forms as ruby and sapphire, so it's practically inert. It's a similar process which makes stainless steel unreactive, though in that case the component which oxidises is chromium.

I think I'd apply a simple subjective chemical test: rub a wet thumb over the metal and then taste it. That would certainly rule out copper, but not the others.

--
Richard Herring <mailto:richard@xxxxxxxxxxxxxxxxxxx>
.

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