A study from Wageningen University & Research in the Netherlands has determined that single serve compostable coffee pods are the most sustainable options when looked at in terms of environmental impacts and circularity.

To make this determination, the researchers examined three different types of single-serve coffee pods featuring those composed of conventional plastic, those composed of aluminum and those composed of compostable biobased materials.

Source: Wageningen University & Research Source: Wageningen University & Research

The researchers explained that they didn’t look at greenhouse gas emissions alone, but instead also considered the circularity of the materials.

Circularity was quantified using the Material Circularity Indicator (MCI), an Ellen MacArthur Foundation-developed tool that considers recycling rates, recycled content, recycling process yield, biobased content, reusability and average lifespan, for instance.

Looking at each pod type in terms of both circularity and greenhouse gas emissions, it was determined that compostable plastic capsules, which are both biobased and biodegradable, were the most sustainable option, with an MCI of 100% (meaning the material is fully circular) when the capsules are composted.

The team explained that both the pod material and the coffee grounds contained within the pod can be kept in the loop as they can reportedly be "organically recycled" through the biosphere into compost and will degrade regardless of whether they are placed in the appropriate container.

The aluminum-based pods were the second-best choice if they are collected separately via systems intended exclusively for returning these pods. Through such a scheme, the aluminum is recycled and the coffee is composted, but this hinges entirely on participation. Yet, the MCI for the aluminum pods is lower — roughly around 60% — versus compostable capsules, even when recycled aluminum is used to manufacture the capsules due to untargeted trace elements accumulating in the recycled aluminum, thereby making it less pliable.

The researchers concluded that the pods composed of conventional fossil-based plastic had an MCI of 50% because neither the pods nor the coffee were recycled.

The article, Sustainability assessment of different types of coffee capsules, details the team’s findings.

To contact the author of this article, email mdonlon@globalspec.com