The Recyclability of packaging materials: the virtuous case of glass

Over the past two centuries, humanity has lived through a period of extraordinary material abundance. Our ability to discover, extract, process, and utilize resources has evolved rapidly, giving rise to a linear economy based on the now-familiar model: “take – make – consume – dispose.“

Today, however, the pressure from population growth and global consumption, combined with the planet’s limited capacity to supply resources and absorb waste, calls for a shift in direction: we must transition to a circular economy. This more forward-thinking vision is built around the principles of “repair – reuse – recycle” (the three Rs), where circularity is not only technical, but also cultural and social.

Comparing Materials: Glass, PET, Aluminum, and Multilayer Composites

Among the items that most affect our daily lives are food and beverage containers. Evaluating them through a sustainability lens means considering technical performance, recycling efficiency, total environmental impact, and the available recycling technologies.

• Glass stands out for its chemical resistance, durability, and virtually infinite recyclability. Although it is more fragile and heavier than other materials, it benefits from a highly efficient single-material collection system. Collected glass is turned into high-quality secondary raw material, minimizing waste and enabling the production of new containers with very low environmental impact.
• PET (polyethylene terephthalate) is lightweight, durable, and widely used, but its recyclability is more complex. It is collected along with other polymers and requires separation. Mechanical recycling can degrade material quality, while chemical recycling, though promising, still has limited efficiency.
• Aluminum, primarily used for cans, is easily separable and recyclable. However, oxidation during use or remelting can reduce its efficiency, representing a weak point in the reuse chain.
• Multilayer or composite materials, such as those used in tetra pak containers, offer lightness and practicality, but pose serious challenges for recycling. Made of multiple layers (paper, plastic, aluminum, adhesives), they allow for the recovery of only the cellulose portion, with significant loss of usable material.

Glass through the lens of a Circular Economy

When considering functional performance, environmental footprint, and maturity of recycling technologies together, glass emerges as one of the most virtuous materials. Its ability to be endlessly recycled without loss of quality, combined with an established industrial chain, makes it an emblematic example of a circular material.

Environmentally, glass requires less energy to produce (around 11 MJ/kg), emits less CO₂ (0.8 kg/kg), and uses significantly less water compared to other packaging materials like aluminum, PET, or multilayer composites. Even during recycling, it maintains excellent performance, with lower energy use and environmental impact than competitors. Its higher density remains one of the few drawbacks, but this can be addressed through design improvements and optimized container profiles to reduce weight without compromising strength.

Glass also aligns well with the three Rs of sustainability, perhaps more than any other packaging material. Some manufacturers already use reuse systems, with bottles washed, sanitized, and put back into circulation multiple times. However, reuse can lead to progressive aesthetic and mechanical deterioration. One area still to be explored is repair, for instance, through surface treatments to restore damaged bottles. This represents an opportunity for glassmakers willing to invest in research and technology.

Lastly, the Italian system for collecting and processing glass waste, known as cullet, is now efficient and mature. The quality of recycled glass depends heavily on the collection and sorting stage, where the absence of contaminants and the use of advanced selection technologies are essential. Even when glass is no longer suitable for new containers, it can be used in upcycling solutions (e.g., fibers, microspheres, insulation), always maintaining the potential for future recycling without quality degradation.

With recycling rates in Italy and Europe exceeding 80%, glass today represents a strategic choice for transitioning to more sustainable production models. There is still room for improvement—especially in reducing weight and extending the useful life of containers—but overall, glass remains firmly among the materials with the highest potential for a truly circular economy.