UC Davis and the PlumpJack Group, which owns two California wineries, are teaming for a two-year study on the effectiveness and quality of screw cap wine closures.

The study, entitled “Bottle Aging — Closure and Variability Study,” will be conducted by the university to shed light on the ongoing debate over whether wine quality and agreeability is compromised by the use of screw cap closures instead of the use of natural or synthetic corks.

The PlumpJack Group owns PlumpJack Winery and CADE Wines, both located in the Napa Valley, and uses both traditional cork and screw cap closures on its products, according to a press release issued in late June by Winebusiness.com.

All closure methods on wine bottles are designed to provide an airtight barrier to keep out oxygen, which can negatively affect aging and taste. The study will use scientific methods — including the new CT scanner invented by UCD researcher John Boone, vice chairman of research in radiology.

“Oxygen is the biggest culprit for wine — it affects taste, color and the aging process,” said Andrew Waterhouse, professor of viticulture and enology at UCD.

“While natural corks have been used effectively for thousands of years, they are no longer a sustainable method of closure. With this study, we hope to scientifically analyze the effectiveness of other closure methods, and thereby to provide information and direction for the industry.”

Freelance writer Laurie Jervis can be reached at winecountrywriter@gmail.com. Her blog is www.centralcoastwinepress.com.

(2) comments


I have to take issue with the statement, “While natural corks have been used effectively for thousands of years, they are no longer a sustainable method of closure.?
WHAT??? They are the ONLY sustainable method of closure.
I hope this is a misquote.
Otherwise this really makes me question the true motives behind this research. Might results of this 'research' already be predetermended??


Corks and screwcaps have very similar barrier properties to atmospheric oxygen. The main source of oxygen in bottled wine is air contact just before and during bottling. Of much greater interest is the ability of corks to adsorb volatile materials from the wine, and the resultant ameliorating effect on the wine.

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