Glass bottles have five to 50 times as many microplastics as plastic bottles

Jun 24, 2025

Looks like the glass is half full…of plastic.

Microplastics are everywhere — in your chewing gum, your beauty products and even your favorite junk food.

Given the name, it’s reasonable to assume you’re more likely to find them in products containing plastic than not.

But a jaw-dropping new study — published in the Journal of Food Composition and Analysis — has discovered that what seems to be the case is quite the opposite.

Guillaume Duflos, research director at French food safety watchdog ANSES, told AFP that his team set out to “investigate the quantity of microplastics in different types of drinks sold in France and examine the impact different containers can have.”

Much to their surprise, they found that glass-bottled beverages — including lemonade, iced tea, beer and soda — had five to 50 times more microplastics than their plastic or metal counterparts.

Needless to say, the team “expected the opposite result,” study co-author Iseline Chaib told AFP.

Researchers found an average of roughly 100 microplastic particles per liter in these glass bottles, which they pinned on the paint on their caps.

“We…noticed that in the glass, the particles emerging from the samples were the same shape, color and polymer composition — so, therefore, the same plastic — as the paint on the outside of the caps that seal the glass bottles,” Chaib said.

They theorized that “tiny scratches, invisible to the naked eye, probably due to friction between the caps when they were stored,” might subsequently “release particles onto the surface of the caps.”

Still, some of the study’s findings remain a mystery.

The team found only 4.5 particles and 1.6 particles of microplastics per liter in glass and plastic bottles, respectively.

And — in more good news — bottles of wine also contained very few microplastics, even when capped.

In contrast, there were 60, 40 and 30 microplastics per liter in beer, lemonade and soft drinks, respectively.

Duflos admitted that the reason behind this inconsistency “remains to be explained.”

While the full health impact of microplastics remains unclear, studies have linked them to inflammation, hormone disruption, DNA damage, respiratory illnesses, heart problems and certain cancers.

ANSES suggests a quick fix: try blowing on the caps and rinsing them with water and alcohol.

The French watchdog found that this method can slash plastic contamination by 60%.