billb@teklabs.UUCP (Bill Beran) (06/29/84)
It is not likely that the wine would see any pressure difference
if it is tightly corked. If it tastes ok, and is not oxidized, then
the corks are almost certainly tight.
The most likely explanation is that, since Rieslings are some-
times bottled with a small amount of residual sugar in more of a
German style, that the wine has started fermenting this remaining
sugar. Since there is no place for the resulting carbon dioxide to
go because the bottles are tightky corked, it goes into solution
where it produces "sparkle". This is sometimes referred to as
"spritz".
This is not an uncommon thing to happen with wines having re-
sidual sweetness. Wineries are generally not pleased with this oc-
curance, as an extreme case will push corks out of the bottles.
A recent bottling by another Oregon winery had the same problem
and they recalled all the wine that was still available to them and
unbottled it, finished the fermentation, and rebottled it. Not a
very cost effective procedure!
This situation is usually prevented by adding a preservative to
inhibit any further fermentation (in the states that allow it) or
providing a completely sterile bottling line and filtration system.
In this way, all viable yeast cells are removed as bottling takes place
and there is nothing to continue the fermentation. Sterile bottling
is tricky in a small winery, but certainly not impossible.
Bill Beran
Imaging Research Lab
Tektronix
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"A day without wine, who needs it?"