Materials Matter: Designing Reuse for the Real World 

One of the most important design decisions for reuse is selecting the right material. It’s also one of the most complex. 

While it would be easier to dictate one material for all reuse systems, the reality is that there is no one-size-fits-all solution. Different materials bring different advantages—and different challenges. Each has its merits for diverse situations and locations––from durability to recyclability, customer experience and cost. The variables are many, and the tradeoffs must be considered to yield the best results.  

In our work to bring reuse to market, we evaluate each material based on how well it fits into a given system: How often will it be returned? How will it be washed and stored? What will the customer do with it after use? Can it be recovered at end-of-life? 

Operational logistics, return rates and customer behavior all play a role in deciding which material is most appropriate. For example, where return rates are lower, lightweight materials with a lower environmental breakeven point are more effective. Where return rates are high, more durable materials will likely have a more positive long-term impact—even if they cost more upfront. 

To illustrate the complex interplay between materials and reuse systems, we explore the tradeoffs of the three most common materials for reusable packaging today: 1) plastic, 2) metal, and 3) glass and ceramic.  

PLASTIC: LIGHTER WEIGHT, LOWER CARBON IMPACT

Plastics for reusable foodservice applications can range from lower-stiffness materials like HDPE or PP, to more rigid resins like PET. 

The Pros 

One of plastic’s key advantages is its light weight. In fact, advances in manufacturing now allow reusable packaging to be lighter without compromising performance. For example, some expanded PP designs feature a lightweight foamed core sandwiched between two solid skin layers, adding insulating air pockets while reducing material use and maintaining durability. Plastics can also withstand being tossed carelessly into a return bin, while stainless steel may dent and glass or ceramic may break. Having a lighter weight per packaging unit translates into a lower purchase cost and smaller manufacturing carbon footprint compared to metal, glass and ceramic.  

In addition to the lower carbon footprint of producing lighter weight materials, the transportation footprint and cost of lighter materials is also comparatively lower. Today, plastic still offers the fastest path to environmental breakeven point for reuse, which is especially important for systems with low or unpredictable return rates. 

Plastic packaging can also be molded into different shapes and colors, increasing brand differentiation and consumer appeal. Plastics are generally perceived as less premium than other durable materials––but that is not necessarily a drawback, in the case of reuse. The lower perceived value may discourage consumers from keeping the packaging forever, supporting higher return rates for returnable packaging models. However, clear communication will be required to ensure customers don’t mistake reusable packaging for single use. When plastic reusable packaging needs to be decommissioned, there is a clear pathway to ensure that these materials don’t end up in landfill. These plastics are accepted in curbside recycling in most cities, and there are strong end markets to keep recycled PET, HDPE and PP in circulation in the U.S. 

The Cons 

Plastic comes with messaging challenges. It can be confusing to “eliminate single-use plastics” and then replace it with another plastic item. Plastic also doesn’t tolerate heat and exposure to acidic foods as well as other materials. It may also stain or retain odors from certain foods, requiring earlier decommissioning. 

Human health is also a concern with plastics. Raw material extraction, processing and manufacturing can create health concerns for workers and communities. Some consumers are starting to think more about the potential health impacts of using plastics, especially for food and beverage. While a scratch in stainless steel is typically only an aesthetic issue, a scratch in a rigid plastic product can be both an aesthetic and food hygiene issue. One concern is the consumption of microplastics, which have been found in tap water, beer, sea salt and tea. Another concern is chemical leaching from additives used to enhance plastic performance. Food-grade plastics used in packaging and foodservice applications undergo rigorous FDA testing and are approved by regulators as safe for their intended use.  

In our study of consumer perceptions of different reusable hot cups, consumers expressed low interest in trying reusable clear plastic cups for hot coffee or tea, and many reported they would throw clear cups in the trash or recycling instead of returning them. Recycled plastic, however, received high interest for trial and return, and consumers showed relatively low concerns related to leaching. 

In summary, plastic can play a critical role in the transition from early-stage activations to a scaled reuse economy. For programs with high reuse rates, plastic is still an option for functional and financial reasons, but metal, glass and ceramic have also become viable options. 

METAL: GREATER DURABILITY, LONGER LIFE 

Metal reusable packaging is often made of stainless steel or aluminum. 

The Pros 

Metal packaging’s key advantages include durability and the ability to provide what many consumers describe as an “improved” or “premium” experience. Metals—especially stainless steel—are incredibly durable. When used for packaging, it retains its quality through many washing cycles, making it ideal for reuse models with high return rates, such as closed-loop settings (for example, school cafeterias) and bring-your-own (BYO) programs.  

Metal is also technically highly recyclable and offers a strong end-of-life pathway—if it’s captured. Aluminum is widely accepted in U.S. recycling systems and has a strong secondary market, with minimum degradation from repeated recycling (in contrast to plastic). However, metal packaging often requires linings to be compatible with many food, beverage and personal care formulas, creating recycling and washing challenges.  

Stainless steel is also 100% recyclable, though not commonly accepted curbside. However, because it is a high-value material, reuse operators can potentially find recovery alternatives for decommissioned packaging via business-to-business recycling.  

The Cons 

The benefits of metal come with trade-offs, particularly higher financial and environmental costs.  

Metals are generally more expensive than plastic, making them less affordable for some businesses and consumers. The process of mining and converting raw materials into metal is also very carbon intensive.  

For certain applications, like hot or frozen items, metal packaging can be polarizing. In one study, we found that one third of consumers prefer metal cups due to insulation and perceived quality, while another third avoid them, often citing taste concerns or discomfort with how hot the cup feels. But context matters. Coffee drinkers may need double-walled steel formats that insulate well, while sport fans might prefer an aluminum cold cup to keep them cool at a summer game.  

GLASS AND CERAMIC: ELEVATED EXPERIENCE, HIGH SATISFACTION

This includes packaging made of borosilicate glass, a type of glass known for its high resistance to thermal shock and chemical corrosion.  

The Pros 

Glass and ceramic offer an elevated consumer experience in many product categories, with consumers defining them as “aesthetically pleasing”. Both materials are well-liked for dine-in environments, in both home and retail settings. These materials are also highly stable and compatible with food and personal care products. They do not retain odors or flavors, and can be effectively sanitized across many use cycles. 

If recycled glass is used, the environmental benefits are notable. Using 10% more cullet––also known as recycled glass––in glass manufacturing can save 2–3% of energy and reduce CO2 emissions by 4–10%. Reuse of glass at scale has also been used for beverage globally. In the U.S., reuse is limited but does exist in programs like Oregon’s BottleDrop Refill and local dairy operations like Straus Creamery and Oberweis Dairy in the Midwest.  

The Cons 

While extremely sturdy and durable overall, one drop on a hard surface, or a collision with another product can result in chips or cracks that render the product unusable. This limits the scalability of returnable programs that depend on broad consumer participation in open systems.  

From a financial and environmental standpoint, glass and ceramic are also costly to manufacture relative to plastic. Both are made from widely available raw materials but have energy-intensive manufacturing processes and high transport emissions due to their weight. Forming raw materials into glass requires melting them at high temperatures, which accounts for 70% to 80% of the energy consumption of the entire manufacturing process and is typically accomplished by burning natural gas. The good news is that according to NREL, glass manufacturing emissions can be reduced by over 80% through recycled content, electrification and renewable energy. .  

One major issue with ceramic is that it cannot typically be recycled—when collected, it is often downcycled into materials like brick or concrete. Glass, on the other hand, is highly recyclable, with established pathways to recover reusable glass at the end of its life, if the right systems are in place. The highest value recycled glass is collected through drop-off programs where it can be sorted by color before it breaks, as mixed color cullet is of little to no value to processors. However, U.S. recyclers face big challenges collecting and sorting curbside glass today. Small-format plastics contaminate glass streams at materials recovery facilities (MRFs)and most glass is sent to landfill. This is a key challenge that the Center for the Circular Economy at Closed Loop Partners is looking to solve through its Consortium to Recover Small-Format Packaging.  

Material Fit Depends on System Design  

This partial analysis illustrates the complexity involved in selecting materials for reuse systems—and the need to go beyond a static lifecycle analysis. Aligning material selection with system design is critical. Because of the complexity and relative novelty of reuse systems in many product categories, innovation and experimentation are more important than ever. As reuse systems evolve, the Center for the Circular Economy’s pragmatic, data-driven and collaborative approach will continue to reduce risk in reuse, and accelerate the scale-up of the materials and systems that work.  

CALL FOR INNOVATION

Are you developing materials or technologies that could reshape reuse systems?

We’re always looking to collaborate with innovators designing and building solutions for real-world systems—solutions that deliver on performance, cost and environmental impact. Contact us at [email protected]

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