Surprise! Glass Bottles Contain Far More Microplastics Levels Than Plastic Bottles, Study Finds

Jun 25, 2025

You might think glass bottles are the safer option, but recent research suggests otherwise. New findings show surprising levels of microplastic contamination in drinks from glass bottles.

In an unexpected finding, beverages packaged in glass bottles were shown to contain significantly higher levels of microplastic contamination than those in plastic bottles. This revelation, which challenges common assumptions about glass packaging, was uncovered in a study conducted by France’s food safety agency, ANSES. The research, released in mid-June 2025, highlighted the alarming presence of microplastics in popular drinks such as soda, iced tea, beer, and even wine.

The study, led by Iseline Chaïb, a doctoral student at ANSES, measured microplastic contamination in various drinks sold across France. The results, published in Journal of Food Composition and Analysis, were startling. The team discovered that beverages in glass bottles contained five to 50 times more microplastics than those in plastic bottles or metal cans.

In particular, drinks like cola, lemonade, and beer were found to have an average of around 100 microplastic particles per liter in their glass containers. “We expected the opposite result,” Chaïb remarked, noting the surprising outcome.

The source of the contamination, the researchers found, was not the bottles themselves but the caps that seal them. More specifically, the paint on the metal caps, which contains plastic materials, was identified as the likely contributor. The researchers observed that the microplastics in the drinks were remarkably similar to the plastic material found in the paint of these caps.

Additionally, the tiny scratches on the caps, caused by friction during storage, appeared to facilitate the release of these particles into the beverages.

While the results for beverages like soda and beer were concerning, the study found that water—both still and sparkling—had much lower levels of microplastic contamination, regardless of whether it was in glass or plastic bottles. In glass bottles, 4.5 particles per liter of water were detected, whereas plastic bottles contained just 1.6 particles per liter.

This relatively low contamination suggests that the plastic particles from the bottle caps were less likely to affect water, which is a less complex liquid compared to sodas or beers that have additional ingredients.

Despite the low microplastic levels in water, the findings underscore the broader issue of microplastic contamination in beverages. While there is still no conclusive evidence that these particles pose a health risk, the presence of microplastics in everyday consumables is raising concerns among researchers, environmentalists, and health experts alike.

In response to the findings, ANSES emphasized that manufacturers could take several simple steps to reduce microplastic contamination. One such solution involves cleaning the caps before use. The researchers tested a method that involved air-blowing and rinsing the caps with water and alcohol, which resulted in a 60% reduction in microplastic contamination.

Guillaume Duflos, the research director at ANSES, explained that these measures could be easily implemented by manufacturers, who are now encouraged to rethink how bottle caps are handled and stored.

While these solutions could mitigate some of the microplastic contamination, further investigation is needed to understand the full extent of the issue, particularly in beverages like soft drinks and beer, which showed significantly higher contamination levels.