Glass is still the dominant force in wine packaging but new formats such as the bag-in-box and PET bottles are gaining in popularity.
This has sparked debates about the merits of different options that the ISVV aimed to settle with a three year study into the influence of packaging on wine preservation.
Rémy Ghidossi, lecturer at the ISVV, said, “It is now necessary to establish the truth, based on scientific information and quantitative data, to determine the legitimacy of each package.”
In pursuit of this goal, the ISVV examined how red and white Bordeaux wine changed over time when kept in glass, single-layer PET, multi-layer PET, and bag-in-box formats.
At regular intervals over a period of one year researchers measured the level of gases (oxygen, carbon dioxide, and sulpher dioxide) contained in the wine. A physical analysis of the colour was also carried out along with a sensory analysis with both expert and novice tasters.
The ISVV said the character of the white wine changed noticeably after six months when stored in single-layer PET, multi-layer PET, and bag-in-box.
Chemical changes
The wine research body said the chemical analysis revealed that plastic packaging allowed oxygen to penetrate after six months, with a major reduction in carbon dioxide. Levels of sulphur dioxide, which helps prevent refermentation and microbial growth, also dropped significantly.
The ISVV said these chemical changes translated into sensory changes – the jury of tasters agreed that the wine tasted of “rotten fruit”.
As for red wine, some initial signs of deterioration were observed in plastic packaging after six months but the ISVV said it is too soon to draw any definite conclusions. An 18-month analysis is now planned in order to build on initial findings.