Oxygen Issues

Do Cork Closures Protect Wines from Dimethyl Sulfide Aromas?
WIne Business Monthly - June 2011, Published CQC survey - April 2011

Summary : Review of literature describing the behavior of Dimethyl sulfide (DMS) in bottled wines. Outlines storage conditions that cause DMS to develop including temperature and the effect of low permeation closures .Includes two market surveys of commercial wines by closure measuring observed DMS by closure type. Concludes that the use of cork closures may reduce the effect of DMS.

 Characteristics of Oxygen Permeability in Wine Closures

Presented by Paulo Lopes PhD, University of Bordeaux - APCOR Cork Seminar - June 2006 - St. Helena CA

Summary : This study incorporates a colorimetric method for detecting oxidation, allowing more precise measurements of oxygen ingress than most previous work. Dr. Lopes demonstrates the comparative differences between wine closures in allowing oxygen ingress. His findings conclude that (1) Synthetics were too permeable – and caused premature aging (2) Screwcaps were not permeable enough – and did not allow proper aging. The implication was that natural cork offered a perfect balance.
Corks as Wine Closures: Post bottling reduction and permeability performance.

Presented by Alan Limmer PhD, Stonecroft Winery NZ - APCOR Cork Seminar - June 2006 - St. Helena CA

Summary : Dr. Limmer’s experience as a New Zealand winemaker gives him extensive familiarity with modern screwcap closures. His presentation explains the source of reduced aromas that can be encountered when a lack of oxygen is present in wine. Dr. Limmer is convinced that many wines suffer loss of fruit and present a characteristic "dullness" when this condition occurs.

AWRI Closure Comparison at 18 Months
Excerpts from the AWRI Closure Report as seen in Australian Journal of Grape and Wine Research 7.64-05.2001

Summary : This presentation is a summary of data presented in graphical form from the oft-quoted AWRI Report on Wine Closures. Much of the data has been selectively reported by various manufacturers of alternative closures. In this display, all of the sensory results are reported together. At the 18-month point there appear to be several conclusions:

  • No single closure demonstrated completely satisfactory results.
  • Synthetic closures had significant issues related to off–aromas and oxidation.
  • Screw caps had better results regarding oxidation but showed evidence of “glue–like” and “reduced” off–aromas.
  • Natural Cork had good marks regarding fruit retention and oxidation. Off–aroma issues were primarily related to TCA.