Here’s why you should avoid wines stored in clear bottles. Regardless of the price, wines in such containers can develop the unpleasant aromas of boiled cabbage, wet dog, and even sewage over time.
This primarily applies to white and rosé wines. The problem is that clear bottles let sunlight in, which can trigger a phenomenon winemakers call “light strike.” Clear glass doesn’t protect wine from ultraviolet radiation or artificial light.
When ultraviolet rays hit the wine, they make amino acids react and form sulfur compounds. Those sulfur compounds cause the off-putting smells that appear in many white and rosé wines—even expensive ones. So if clear-bottle wines are exposed to light, they can taste worse than cheap wine stored in colored bottles.
Under direct sunlight, a wine’s flavor can start to deteriorate in as little as 30 minutes, according to the Daily Mail.
What Researchers Discovered
A 50-day study by a team from the University of Trento (Italy) found a significant increase in the levels of a compound called 4-hepten-1-ol in wines like Chardonnay and Pinot Grigio stored in clear bottles. “These foul-smelling compounds, responsible for the unpleasant taste of boiled cabbage, form in wine exposed to light,” the researchers wrote in their report for the journal PNAS.
After just one week of sun exposure, wines stored in clear bottles also showed a big drop in the chemicals that create pleasant flavors.
Specifically, the wines lost between 10 and 30 percent of terpenes—compounds that provide floral and fruity notes—and between 30 and 70 percent of norisoprenoids—compounds responsible for complex resinous notes.
In contrast, wines in colored bottles did not show an increase in unpleasant chemicals and maintained their pleasant flavor throughout the study period.
“Daylight Robbery”
What about red wines? They actually fare better under light exposure because they have higher polyphenol levels. Those grape-derived compounds take longer to break down in light, so red wines retain their flavor for a longer time.
As a result, delicate white and rosé wines stored in clear bottles are the most affected by “light strike.” Unfortunately, producers often choose clear glass to showcase a wine’s color.
“The scale of this problem is likely much larger than any other wine faults,” commented wine expert Suzy Barry about the findings. “For the most part, we continue to pretend this isn’t an issue, while it actually robs us of the legitimate pleasure of wine. It’s daylight robbery,” she added.
Some experts recommend storing wine in a cool, dark place away from direct sunlight. Other researchers, looking at recent studies, say it’s better to avoid buying wines in clear bottles altogether.
Mark Driver, a winemaker from Sussex, UK, advises, “The next time you want to buy a rosé or a delicate white wine, like Pinot Grigio, look for a bottle in dark green or amber.”
