Keep bag-in-box wines cool, says UCD

When it comes to wine, if you bag it and box it, you’d better keep it cool, UC Davis researchers advise.

In the most comprehensive study to date on how storage temperature affects wines with different packaging systems, researchers found that bag-in-box wine is more vulnerable to warmer storage temperatures than bottled wine. Their findings are reported online in the American Chemical Society’s Journal of Agricultural and Food Chemistry.

“Earlier research has compared bottled wine with bagged wine or bottled wines capped with different closures, but this is the first comparison of all of the different packaging configurations under different storage temperatures,” said lead researcher Helene Hopfer, a postdoctoral scholar in the department of viticulture and enology.

“In addition, this was the most comprehensive wine packaging and storage study, examining the effects of temperature on aroma, taste, mouthfeel and color, and correlating those changes with measurements of chemical and physical changes,” said Hopfer, who collaborated on the study with enology professors Susan Ebeler and Hildegarde Heymann.

The researchers used chemical analyses and a panel of trained tasters to analyze how storage at three different temperatures affected California chardonnay in five different packaging configurations: glass bottles with either natural corks, synthetic corks or screw caps, and two kinds of bag-in-box containers.

The wine was made from grapes grown in Monterey County and fermented in stainless steel tanks, rather than oak barrels.

The researchers found that warmer storage temperatures produced the most significant changes in the wine, and those changes were more pronounced in the bag-in-box wine than any of the bottled wine.

Bagged wine stored at 68 and 104 degrees Fahrenheit aged significantly faster than did the bottled wine, becoming darker and developing sherry-like, dried fruit-like and vinegar-like attributes. Many of the observations made by members of the sensory panel who tasted the wine were confirmed by chemical analysis.

The researchers found that all of the wines analyzed aged better when they were stored at 50 degrees Fahrenheit.

“The way a wine looks, tastes and smells is affected by the way certain wine compounds react with oxygen,” Hopfer said. “Those reactions speed up at higher temperatures, so differences in the way packaging systems manage oxygen in the container become critically important to aging and stability of the wine.”

The researchers have conducted a very similar study using the same packaging configuration and storage temperatures with cabernet sauvignon wine. A paper reporting the results from that study has been submitted for journal publication.

Constellation Brands and ACI CORK USA provided wine samples and packaging materials.

— UC Davis News Service