PE.DI unveils results from the first on-Site study on the impact of crown caps on sparkling wines

Published on May 30, 2024 by Pierre PETITJEAN

At the Sparkling Wine Forum in Brescia, PE.DI (part of the Crealis group), a company specializing in the production of crown caps for traditional method sparkling wines, revealed the findings of the first enological study on the impact of crown caps used during sparkling wine fermentation. The crown cap, the final link in the production process, plays a pivotal role in managing aging on lees and significantly influences the wine's organoleptic profile.

 

This study is the result of a collaborative effort primarily involving Virginie Thollin (consultant for PE.DI of the Crealis group), Gérard Liger-Belair (Effervescence & Champagne Team - GSMA – UMR CNRS 7331 – University of Reims Champagne-Ardenne), and Bertrand Robillard (Institut Œnologique de Champagne).


 

The Crown Cap for Sparkling Wine Fermentation: A Key Element in Managing Dissolved Gases

In the 19th century, Louis Pasteur (1822-1895) famously said, "oxygen is the greatest enemy of wine, but also oxygen makes the wine, which ages under its influence ".  Today, two centuries later, managing oxygen remains a critical concern for producers of both still and sparkling wines.

 

The majority of winemakers use crown caps, consisting of a metal shell and a synthetic liner, to seal their bottles. After bottle fermentation, during aging on lees, the cap is perfectly liquid-tight but not gas-tight. The carbon dioxide pressure inside the bottle gradually decreases during this aging period, while oxygen from the surrounding air slowly diffuses through the crown cap's liner, entering the bottle. This initiates a gradual oxidation process of the wine.

 


Context of the Study

As a producer of crown caps, PE.DI embarked on an in situ study to gain deeper insights into the impact of its various liners on gas transfers and their implications for wines during aging on lees. In April 2017, two "blanc de blancs" cuvées (made exclusively from Chardonnay grapes) were bottled under production conditions and sealed with the following liners: TOP, TOP+3, TOP+, TOP Z, TOP S, and Oxysorb.

 

PE.DI identified three technical areas to investigate while monitoring these bottles during their aging on lees:

  • CO₂ losses, to characterize the wine’s effervescence potential.
  • Oxygen ingress, responsible for oxidation reactions and alterations in the wine’s organoleptic properties over time.
  • Tasting, the final criterion in wine production.


Firsts Conclusions

The real surprise is in the caps being more airtight than expected! New measurements of CO₂ losses through crown caps with synthetic liners, under aging on lees conditions, are two to three times lower than those previously recorded by the Comité Champagne in bottles of carbonated water.


From an organoleptic perspective, following the first year of aging, a panel of Champagne experts has already noticed differences in the aroma and flavor during blind tastings.

 

This study highlights the crucial role played by the crown cap and its liners during aging on lees. Winemakers have a valuable enological tool at their disposal that should not be underestimated! However, the study also emphasized the importance of proper implementation of this tool through specific sealing, which must be correctly executed before considering a crown cap permeability strategy tailored for different cuvées.


Discover more about Pe.DI: https://www.crealisgroup.com/en/international/home-international/