Screwcap vs. cork takes on a new odor

When one speaks of a wine's "nose," rotten eggs does not come to mind. But it sometimes could, according to a British study conducted by something called the International Wine Challenge (IWC) of London.

Analysts said 2.2% of screwcap wine bottles were affected by a chemical process called reduction that gives wine a sulphurous, or rotten egg, smell as soon as the bottles are opened. Although the same process can happen with wine stoppered by natural cork, the porous composition of cork allows oxygen to dilute the odor.

It can occur in wines stoppered by screwcap or cork, but cork's porous nature allows oxygen to dilute the smell.

Tests conducted on 9,000 screwcap wines by the IWC found 2.2% were affected by sulphidisation because the wine was not allowed to breathe. If extrapolated worldwide, that would result in 200,000 affected bottles. The IWC also found that 4.4% of cork-stoppered bottles also suffered sulphide problems but, as noted, since corks allow oxygen to pass through, the smell dissipates.

Malcolm Gluck, a noted British wine writer who is the wine critic for the Guardian newspaper in London, told the BBC Online that any concern is largely overplayed.

"It's rubbish," he said. "Any bottle can suffer from sulphidisation. Even organic wines have to have sulphur" as a preservative.

The problem, Gluck said, is with a minority of producers who have not yet gotten the level of sulphur right, when wine is sealed with a screw top, rather than a cork, which allows a small amount of air in over time.

To Dowd's Spirits Notebook latest entry.
To Dowd's Wine Notebook latest entry.
To Dowd's Brews Notebook latest entry.
Back to Dowd On Drinks home page.