"Tom S" > wrote in message
m...
>
> Why do you say that last? The presence of oxygen would in no way
forestall
> an incipient H2S or mercaptan problem in a screwcapped bottle. Only prior
> cellar treatment can avoid that. Wines bottled cork finished can have H2S
> and mercaptan problems too.
Because a little oxygen (which can get around the outside of an imperfectly
cork seal) will oxidise the H2S, thus removing it. A well sealed cork will
retain H2S, as you pointed out. The problem is that there are a lot of badly
sealed cork!

At our winery, having gone to screwcaps where possible, now check the wine
with a little dose of copper prior to bottling. If we can't pick the
coppered wine as being less preferred, then we add it as a matter of course.

My view of screwcaps is that, as with any new technology, you can't just go
in and do everything that you used to do. You have to assess how things have
changed, and how you will react to that change. And this is what many people
have not done, and why we are seeing teething problems with screwcaps. Give
it a few years, and people will figure out what they need to do to counter
the "bad" things.

Cheers,

Andrew
P.S. Does anyone have any good ideas for non-cork seals for sparkling wine?
And I mean ideas that won't put off customers - we've considered crown
seals, but they might be a little off-putting to the ponces trying to
distance themselves from beer. And, having disgorged a few thousand bottles,
I know that crown seals can become lethal missiles more readily than corks!