The way in which green coffee is stored is key to cup quality: effective storage maintains the cup profile of a coffee, while poor storage can detract from it. Additionally, there are several factors to consider when storing green coffee, with preserving freshness being the priority.
As raw coffee is particularly sensitive to external factors, including temperature and moisture, maintaining freshness is an essential part of storage. That said, minimising environmental damage at this stage of the supply chain is also crucial – especially as the demand for more sustainable coffee grows.
As concerns around packaging waste increase, more importers are looking for eco-friendly ways to package their crops for shipping. So, how can coffee buyers and traders keep their green coffee properly stored while also staying sustainable?
I spoke with Shaun Aupiais, the co-founder of Red Band Roasting Academy, to learn more about whether green coffee can be stored in compostable packaging.
Green coffee qualities: Key factors
The unique qualities of green coffee are the essence behind a roasted coffee’s taste, aroma, and body. Green beans are high in acids, lipids, proteins, and sugars. These are responsible for producing over 800 aromatic compounds after roasting.
Besides the well-known factors behind the coffee quality, such as variety, terroir, and post-harvest processing, optimal storage conditions are crucial. To some extent, freshness is the overarching feature that expresses the essence of raw coffee as the opposite of degradation.
In this regard, storage is the best way to protect the unique qualities of green coffee, particularly as it usually travels for weeks or even months before roasting.
Most experts agree the most determinant factors affecting green coffee quality are temperature, humidity, and moisture content.
- Temperature: Green coffee should be stored between 20 and 25ºC (68 to 77ºF). Changes in temperature can dramatically alter the chemical composition of green coffee and ruin its aromatic profile.
- Humidity: Relative humidity should range between 40% and 70%. Depending on the moisture content of the beans, lower or higher relative humidity may be required. Relative humidity can damage high-quality green coffee as it is porous and will absorb oxygen and water quickly.
- Moisture content: It’s common practice to look for moisture content within the 10-12% range. While some coffee producers and buyers dry raw coffee through sun exposure, it can be a risky practice that must be strictly controlled to avoid undesired effects on green coffee. Alternatively, high moisture content can lead to mould and mycotoxin generation.
Arguably, optimal storage must also factor in warehouse conditioning, transportation, and other variables. Yet, research has found that packaging is the most determinant factor in optimal storage.
Trabocca conducted a 3-year study to assess the impact of warehouse conditioning and packaging on the quality of green coffee. Results suggest that hermetically sealed packaging can protect green coffee from deterioration, even inside an unconditioned warehouse.
Traditional packaging materials for green coffee
When raw coffee is shipped, it is usually packaged in bags which are strapped to wooden pallets. This helps to create a more efficient means of transport. Some of the most common materials used to store green coffee are burlap, permeable plastic, high-barrier plastic, and vacuum.
While jute or burlap sacks are economical, they’re less effective at protecting coffee when used alone. This is why they are commonly lined with GrainPro. This plastic-based material ensures a more effective barrier against oxygen and water but often lacks sustainability.
When coffee is vacuum packed, the oxygen levels are drastically reduced, ensuring the coffee remains fresh for longer periods. Yet, the majority of this packaging is not reusable, compostable, or recyclable, making it unsustainable in the long run.
Regarding sustainable alternatives for green coffee packaging, two materials stand out: polylactic acid (PLA) and low-density polyethylene (LDPE). Both materials offer unique advantages for storing green coffee.
For instance, PLA offers excellent oxygen and water vapour barrier properties. This makes it an effective option for green coffee packaging, as it can keep moisture content and temperature levels stable over time. Additionally, PLA is biodegradable and compostable, which makes it environmentally friendly.
Similarly, LDPE offers superior barrier properties against oxygen and water vapour, ensuring an optimal environment for coffee storage. More so, this material is flexible and lightweight, making it easy to handle and cost-effective to transport. Although LDPE is fully recyclable, it is not biodegradable or compostable, unlike PLA.
By choosing compostable packaging to store rawcoffee, producers, and retailers can reduce their environmental footprint while ensuring optimal protection for the product. In addition, sustainable packaging reduces waste and contributes to a circular economy model.
“Under all circumstances, we need to consider the longevity of the packaging and how that would impact the quality of the coffee, especially over the duration of time it takes to arrive at the client to the time they use it,” explains Shaun, who is also a contract roaster and coffee educator.
“I suppose in some ways it’s a positive thing as it forces the receiver to use the product as soon as possible,” he adds. “Hanging onto coffee for too long defeats the purpose of the task at hand, especially if we are sample roasting with the intention to purchase green beans.”
Can raw coffee be stored in compostable packaging?
Obviously, protecting coffee from variations in temperature and humidity is crucial, not only for its aroma and taste but also for safety reasons. That’s why choosing high-quality, sustainable materials appropriate for green coffee packaging and storage is essential.
Fortunately, research has found that compostable packaging can also protect green coffee. It can be a stable, flexible, resistant, and hermetic alternative to conventional plastics.
“Without a doubt, there is an option to ship coffee in compostable packaging,” explains Shaun, who is also a contract roaster and coffee educator. “While there would be a few things to consider, such as the quality of packaging and the cost involved, I believe the overall impact on the environment would be massive if each and everyone did their part to make a difference.”
Cafe Imports recently made the shift to compostable bags for green beans. Since December 2022, the coffee importer based in Minnesota announced it is using 100% compostable sample bags for transporting and storing green coffee.
Except for the zipper, the Cafe Imports sample bag is certified as home compostable by three gold standard certifications in different regions: OK Compost in Eurozone, BPI in the United States, and ABA Home Compost in Australia and New Zealand.
The bags are designed to fully decompose in 12 months. Furthermore, 90% will break down within 90 to 120 days in a home compost heap, which can have different conditions than industrial compost processing facilities. The resealable zipper is thick enough for commercial composting, but it may take longer to decompose in a home compost heap.
Since the sample bags have a shelf life of 12 months, they cannot currently be used for shipping 60kg bags of raw coffee. Therefore, Cafe Imports explains it will continue to use GrainPro bags for this purpose.
Overall, compostable packaging is an excellent option for storing green coffee. It offers the same stability and resistance as conventional plastic while being more sustainable and eco-friendly. Although compostable packaging can’t be used for transportation or storage for long periods, research continues to show promising results about compostable packaging’s effectiveness in protecting raw coffee beans from environmental factors.
At MTPak Coffee, we understand the need to create unique coffee packaging to make your brand stand out, whether you’re selling in retail bags or offering coffee samples.
We offer 100% recyclable LDPE packaging that uses just two layers, compared to the three or four in many coffee bags around the world. Furthermore, our range of coffee packaging solutions includes compostable and biodegradable materials made from renewable sources. This includes kraft and rice paper, as well as LDPE and PLA.
We also offer a line of hermetic green coffee storage and sample bags, complete with resealable zippers for added security and flexibility.