Study: These Types of Single-Serve Coffee Capsules Are Worst for the Environment

Artist’s rendering of a coffee capsule.

After conducting a sustainability assessment of three different types of single-use coffee capsules by material type, researchers in The Netherlands concluded that conventional plastic is the worst for the environment in terms of recyclability and circularity. 

Also not totally shocking: Compostable bio-based capsules were found to have the least negative environmental impacts among the capsule types, even when they are discarded in the “wrong” place. 

Aluminum capsules were found to be the next best choice for environmental circularity due to recyclability, though recycling availability and participation rates remain low, the authors noted. 

Published by the research arm of Wageningen University, the study explored the potential environmental circularity of commonly used single-serve capsule types, as well as their greenhouse gas emissions.

Additionally, the 72-page paper provides numerous recommendations for industry stakeholders and policy makers, while challenging some of the common sustainability messaging from large coffee companies and packaging manufacturers. 

[Semantics note: In the study, the term coffee “capsule” refers to single-use capsule or “pod” types that are compatible with Nespresso brewing systems, which are the most popular single-serve systems in the Dutch market, according to the researchers.]

When a Capsule Dies

The study examined three primary single-use capsule types: bio-based compostable (as opposed to oil-based); aluminum; and conventional oil-based plastic. 

To evaluate the potential circularity of the capsule types, the researchers used the Material Circularity Indicator (MCI), a tool developed by the Ellen MacArthur Foundation that takes into account recycling rates, recycled content, recycling process yield, bio-based content, reusability and average lifespan. 

Using this tool, the researchers explored the following end-of-life scenarios for used capsules: industrial composting (for compostable capsules only); recycling via waste collection; incineration with energy recovery; landfill with energy recovery; and mono-collection (for aluminum only). 

The ‘Most Sustainable Option’

Compostable Capsules

“When taking into account both greenhouse gas emissions and circularity, the main conclusion is that compostable plastic capsules are the most sustainable option,” the researchers stated. “Both coffee grounds and capsule material can be kept in the loop as they are ‘organically recycled’ via the biosphere into compost. Compostable options remain sustainable even when consumers dispose of the capsules in the ‘wrong’ container. Currently in the Netherlands, the main hurdle is getting compostable coffee capsules accepted in the separately collected municipal organic waste.”

Aluminum Capsules

The study found that aluminum have high potential for circularity, but only if they are collected through systems designed specifically for that capsule type (mono-collection), with the aluminum recycled and coffee composted. Notably, Nespresso has promoted its aluminum capsule recycling infrastructure as a sustainability initiative. 

“In case stakeholders want to improve the sustainability of aluminum capsules, the only full circularly pathway for both capsule material and spent coffee grounds is the mono-collection system,” the authors wrote. “This system is currently impaired by the low participation rates and stakeholders are recommended to incentivize collection with deposit refund systems that could potentially achieve the required near 100% collection rates.”

Conventional Plastic Capsules

Lastly, the researchers concluded that traditional fossil-fuel-based plastic capsules “do not fit” in a circular economy, since in most recycling schemes, the plastic capsules.

The “Coffee is Food Waste” Problem

Throughout the study, the researchers noted the particular problem caused by single-use coffee grounds, as they stick to all three capsule materials and are generally considered “food waste.”

In The Netherlands, and most other jurisdictions with government-led recycling schemes, materials with food waste are not recyclable without additional industrial processing. 

“In general, policy makers should be aware that setting policy targets only for packaging materials can result in non-sustainable outcomes, especially when the products concerned are composed of packaging materials and food residues at the moment of discarding, such as is the case for coffee capsules,” they wrote. “In these instances a more appropriate policy should ideally include targets for the contained food product as well.”

Find the full study here. 

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