Research shows oxygen management during bottling and closure selection critical to wine quality.(05-11-2009)
Zebulon, N.C., (May 11, 2009) - Initial results of a German study from the Geisenheim Research Center clearly demonstrate that oxygen control during bottling has a significant effect on wine development. In fact, researchers found that if bottling processes weren't managed appropriately, it caused irrevocable damage to the wine and its post-bottling development.
Consistent with recent findings from a French study that revealed that oxygen transfer rates (OTRs) through a wine bottle's closure can be a primary influence of wine development over time, this study shows that the combination of controlled bottling and a closure with the appropriate OTR enables winemakers to effectively manage the wine aging process and minimize the occurrence of fault and inconsistency.
Initiated by Nomacorc, the world's leading producer of alternative wine closures, and carried out by the Geisenheim Research Center, the study began in July 2008. It explores the influence of different bottling conditions on Riesling grape development, specifically:
"Ultimately, we found that if bottling conditions are well-managed, then oxygen transfer rates (OTRs) through the closure influences wine evolution in a more pronounced manner," said Dr. Stéphane Vidal, global director of enology for Nomacorc. "Conversely, before winemakers can shape wine evolution through closure OTR, oxygen ingress at bottling must be under control."
Research Setup and the Role of Headspace
"Our results show that headspace oxygen, which has largely been ignored by the industry, is a very critical factor impacting wine development and more specifically, a wine's oxidation resistance influencing shelf-life performance," said Dr. Rainer Jung, scientist and vice chair of the section of enology and wine technology at Geisenheim Research Center.
Historically, the industry has focused exclusively on monitoring dissolved oxygen levels during bottling due to the inability to measure in tandem the headspace oxygen content. It was believed that because the headspace volume is rather small, its oxygen content would be insignificant compared to the dissolved oxygen. Using the PreSens technique, the Geisenheim research determined that the headspace in fact represents a significant reservoir of oxygen that contributes to wine evolution. As a result, winemakers measuring only dissolved oxygen underestimate the risk of oxidation in their wines.
The research project design evaluated the evolution of a Riesling under different bottling and post-bottling conditions. Bottles were filled using two headspace volumes, each containing three different concentrations of oxygen emulating conditions typically encountered during actual bottling. The wines were then exposed to three closure conditions with varying OTRs.
Interpretation of Findings
"By optimizing certain processes on the bottling line and diligently monitoring and controlling headspace and dissolved oxygen levels, winemakers and retailers can extend the shelflife of a wine and improve its consistency," said Vidal. "Once bottling conditions are under control and oxygen ingress is minimized, winemakers can then select a closure with an optimum OTR to drive wine evolution.
"With the new PreSens tool and our research findings with Geisenheim, Nomacorc hopes to provide recommendations to winemakers that will help them improve the performance of their bottling lines,"added Vidal. "Our intention is to mobilize our team of highly skilled enologists so that they can directly support our customers and assist them in optimizing their bottling operations and ensure proper closure selection."
Nomacorc's Oxygen Management Research Program
"Nomacorc has been a close and substantial collaborator through this research process and innovative in the field of post-bottling chemistry and oxygen management research," said Dr. Jung.
Contact: Katie Myers