Study questions stores’ freshness claims on plastic wine bottles

The year-long study, which was carried out by the Institute of Vine and Wine Sciences (ISVV) in Bordeaux, found that the flavour and chemical composition of white wine changed within six months of being packed in single- and multi-layer PET bottles and bag-in-box.

The wine, however, remained stable in glass bottles, the study claimed. Red wine was also more stable in the non-glass formats, the study found.

The ISVV’s results contradict recent claims from major retailers including Marks & Spencer and Waitrose over the shelf life of wine packed in PET bottles.

Both have launched wines in the format for the summer season, claiming environmental benefits due to their lighter weight compared to glass bottles.

Lab-condition tests
The ISVV tested both red and white Bordeaux wines which were packed in a range of glass, single-layer PET, multi-layer PET and bag-in-box packaging and then stored in laboratory conditions.

Researchers then tested the level of oxygen, carbon dioxide and sulphur dioxide in the wine, as well as its taste and colour intensity, and regular intervals over the year.

While gas levels and taste of white wine were found to changed in the plastic and bag-in-box packs over the year, there was little change in the red wine and the ISVV is planning to continue testing into a second year.

ISVV lecturer Rémy Ghidossi said, “A lot of contradictory information has been circulating in recent months regarding different packaging solutions suitable for wines.

“It is now necessary to establish the truth, based on scientific information and quantitative data, to determine the legitimacy of each package, as its main function is to preserve the flavour and characteristics of its content.”

Rise of PET format
The study has published just a week before the London International Wine Fair and comes at a time when major retailers are looking to PET bottles as a lightweight alternative to glass.

Marks & Spencer last week launched a range of 19 wines in mini 25cl multi-layer PET bottles, saying that the wines were guaranteed to stay fresh for 12 months. 

Waitrose has also launched two of its wines in PET bottles that it is aiming at the outdoor summer market, especially festivals such as the Henley Regatta and Glastonbury.

Waitrose wine buyer Nick Room said the bottles of South African wine brand Khula Sky’s Shiraz and Chenin Blanc had a shelf-life that was guaranteed for 12 months and were proven for 24 months.

He said the shelf-life of the format, which includes an oxygen barrier, highlighted “that the product is as good as glass for wine quality”.

“Wine-drinkers can be quite precious about compromising taste and quality, which is something we have been very careful to ensure doesn’t happen with the new plastic packaging,” he said.

For more on wine packaging, see the June issue of Packaging News.

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