Imagine buying exceptional specialty coffee, only for it to arrive with a musty odour and baggy flavor – all because of poor green bean storage.
Green coffee is extremely porous and easily absorbs flavors and aromas, which means it’s important to be careful during storage and transportation. Producers, buyers, and roasters shouldn’t overlook factors such as humidity, light, and temperature.
To learn more about how to safely store and transport green beans, I spoke to Hanuman Jain, CEO of Ecotact, a seller of nine-layered airtight/hermetic green coffee bags. Here’s what I discovered.
Spanish Version: Almacenamiento de Granos Verdes: Factores que Debes Controlar
A coffee storage facility in Brazil. Photo Credit: Julio Guevara
“The temperature and humidity of the warehouse are critical factors,” says Hanuman.
Beans that are too wet can become moldy, while beans that are too dry can lose their flavors and aromas. According to the International Coffee Organization (ICO), coffee beans that are in storage should have a humidity level of around 11–12.5%. However, some roasters and producers prefer to dry their beans to 10 or 10.5%.
Regardless of the precise moisture level, it’s important that it doesn’t change during storage. This means you need to control your warehouse/transportation temperature and also, Hanuman tells me, the oxygen levels within the bag.
Yes, the oxygen levels. This is because humidity is the amount of water vapour present in the air. If air can get in and out of those bags, so too can moisture.
Green coffee beans have been transported in jute or burlap sacks for decades. These have many advantages, such as their affordability, but they are not hermetic or airtight. They will allow moisture into the coffee if it’s present in the external environment – something which can be hard to control during transportation or in particularly humid environments.
On the other hand, single-layer plastic bags can lead to condensation building up inside, especially when there are fluctuations in the temperature. In turn, this can fade/bleach out your green beans. Say hello to fresh coffees that taste like past crops, with reduced aroma, acidity, and flavors.
Green coffee bean samples ready for analysis in San Marcos, Honduras. Photo Credit: Amec Velásquez
Have you ever heard that “if it’s comfortable for you, it’s comfortable for your coffee”? When it comes to temperature, anything too hot or too cold can impact moisture levels. We’ve already discussed the importance of keeping the temperature stable; now let’s look at which temperatures are best.
Sweet Maria’s recommends that green beans are stored at “room temperature,” which generally falls between 20 and 25ºC (68 to 77ºF). Hanuman tells me, however, that it also depends on the packaging. Hermetic packaging, he advises, will protect coffee beans in warehouses with temperatures anywhere between -30 and 90ºC (-22 to 194ºF).
Coffee beans stored in Ecotact hermetic packaging inside burlap sacks. Credit: Ecotact
Once your green beans have finished drying, keep them out of direct sunlight to avoid prematurely aging then. Green coffee should stay fresh for up to twelve months, or more with multi-layer and/or hermetic packaging. However, if kept under bright lights, you can expect the flavors and aromas to begin fading earlier than expected.
Green coffee beans, ready to be roasted. Credit: Clandestino Roasters
Pests that are inside the coffee bags can feed on the packaging, creating holes, or sometimes even the green beans themselves. With traditional fabric bags, this can be a cause for concern; some producers choose to use pesticides to prevent the issue. Hanuman points out that hermetic bags can reduce the issue, however, because the insects won’t be able to survive without fresh air. “Whatever insect is left inside, it dies within a day or 48 hours,” he says.
Honey processed coffee stored in Ecotact hermetic packaging. Credit: Ecotact
Every type of packaging has an environmental impact. Traditional burlap and cotton bags have some of the smallest eco-footprints, but you should also consider the impact of damaged coffee that needs to be discarded or replaced. If you choose to use plastic hermetic packaging, Hanuman tells me that the bags are often reused, helping to make them more green.
Burlap sacks used to store green coffee beans. Photo Credit: Julio Guevara
When producing, buying, and roasting specialty coffee, no element is so small that you can overlook it. Poor storage and transportation can have a costly impact on your green beans. Remember to control your temperature, moisture content, light levels, and more to ensure your coffee remains at its best.
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