French researchers discover that your “environmentally friendly” glass bottle drink contains up to 50 times more microplastics than plastic bottles, with dangerous particles coming from a surprising source.
Key Takeaways
- Glass bottles contain 5-50 times more microplastics than plastic bottles or cans, according to ANSES, France’s food safety authority
- The paint on bottle caps is the primary source of contamination, with particles matching the color and composition of cap paint
- Beer showed the highest contamination levels, while wine and water had much lower microplastic content even in glass bottles
- Cleaning bottle caps with alcohol and water can reduce contamination by up to 60%
- Health impacts remain unclear, but microplastics have been linked to inflammation and hormone disruption
Glass Bottles: An Unexpected Source of Microplastics
A shocking new study has revealed that beverages in glass bottles contain significantly higher levels of microplastics than those in plastic containers or metal cans. The research, conducted by ANSES (France’s food safety agency) and published in the Journal of Food Composition and Analysis, found that glass-bottled drinks contained five to fifty times more microplastic particles than their plastic-bottled counterparts. This finding directly contradicts the common belief that glass packaging is a cleaner, safer alternative to plastic when it comes to food and beverage containers.
The researchers themselves were stunned by their findings. “We were expecting the opposite result when we compared the level of microplastics in different drinks sold in France,” said Iseline Chaïb, researcher at ANSES. The study focused on a variety of beverages available in France including cola, lemonade, iced tea, beer, water, and wine. Glass-bottled beverages contained an average of 100 microplastic particles per liter, with beer showing the highest contamination levels followed by lemonade and soft drinks.
NEW – More microplastics in glass bottles than plastic: studyhttps://t.co/CUMmH6S4LG
— Insider Paper (@TheInsiderPaper) June 20, 2025
Cap Paint Identified as Primary Contamination Source
After extensive analysis, researchers pinpointed the painted caps of glass bottles as the main source of contamination. The microplastics found in the beverages shared the same shape, color, and polymer composition as the paint on the bottle caps. The team discovered that the paint had tiny scratches, likely caused by friction during handling and transportation, which released microplastic particles into the drinks. This connection was further confirmed when researchers observed that the concentration of microplastics decreased when bottles were stored upright rather than on their sides.
“We then 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,” said Iseline Chaib, researcher at ANSES.
Interestingly, wine bottles exhibited much lower levels of microplastics despite also being packaged in glass. Guillaume Duflos, one of the study authors, admitted this disparity remains unexplained. Possible factors could include differences in bottle cap materials, storage conditions, or properties of the beverages themselves. This anomaly highlights how much we still don’t understand about microplastic contamination in everyday products.
Health Implications and Reducing Exposure
The health effects of consuming microplastics remain largely unknown, creating a concerning gap in our understanding of these ubiquitous contaminants. The ANSES researchers noted they did not assess health risks in this study due to the lack of toxicological reference data. However, previous research has found microplastics in human tissues, including the brain, and some studies have linked microplastic exposure to inflammation, hormone disruption, and other health issues. The growing prevalence of microplastics in our environment and food supply makes this an urgent area for further research.
“The reason for this discrepancy remains to be explained,” said Guillaume Duflos, one of the study authors.
For concerned consumers, the researchers offered a practical solution: cleaning bottle caps before consumption. Simple methods like blowing air and rinsing caps with alcohol and water can reduce microplastic contamination by up to 60%. This straightforward approach offers an immediate way to lower exposure while waiting for industry standards to evolve. The findings challenge the environmental narrative that has long promoted glass as the cleaner packaging option, suggesting manufacturers may need to rethink bottle cap designs and materials to reduce microplastic shedding.
