How to Store Your Green Coffee Beans
All great coffee roasters know that the key ingredient to running a successful coffee shop is brewing high-quality coffee. It begins with high-quality beans and continues with a good roasting system and a good brewing system. However, the quality controls that lead to cup-after-cup of delicious coffee begins before roasting. This is where proper storage practices of your green coffee beans come into play. From harvesting to brewing, how your coffee beans are stored will determine how your customers experience your coffee. Since the coffeehouse culture exploded in the United States in the ’90s, expertise on how to store coffee beans has grown.
What Are the Different Methods of Storing Green Coffee Beans?
Green coffee beans are porous and hygroscopic. This means they readily absorb and retain moisture. For example, if you store your fresh green coffee beans near garlic – the beans will take on the aroma and flavor of garlic!
When the average person thinks of bulk coffee storage, images of burlap or jute sacks of coffee beans come to mind. Pictures of farmers with stacks of these bags are common. The truth, however, is that storing porous coffee beans in porous bags leads to problems with moisture content. On the other end of the spectrum from permeable woven bags, are plastic bags. The problem with plastic bags is that condensation builds up. So again, there are problems with moisture content. This can lead to faded green beans and reduced aroma and flavor. It can also lead to moldy beans.
Too porous and not porous enough are the two extremes of packaging coffee beans. Fortunately, packaging experts continue to innovate, taking the following vital aspects of coffee bean storage into account:
- Moisture levels
- Temperature levels
- Light levels
- Storage and packaging options
Moisture levels of green coffee beans change as they make their way from harvesting to roasters. When coffee beans are picked but not yet processed, they contain about 50 percent moisture. By the time the raw beans are packaged for shipment by producers, the moisture content has reached about 11 percent. This is the moisture level recommended by the International Trade Center. Note: some specialty coffees have different moisture standards.
As you can see, the margin for error from shipping to brewing is very small. When the coffee beans have been stored in an environment where the humidity is stable (about 60%), roasters can feel confident they are brewing fresh coffee. Higher humidity will result in mold growing on your beans. Lower humidity will result in your beans drying out and losing flavor. Moisture levels are a significant quality control issue.
As air temperature rises, it can retain more water molecules. In other words, warmer air means more moisture in the air and cooler air means less moisture in the air. This leads to the logical conclusion that cool air is better for green bean coffee storage. Many experts suggest storing beans at room temperature. Depending on who you consult, room temperature could mean anywhere between 60 degrees or 77 degrees Fahrenheit.
You’ve probably heard of freezing or refrigerating beans. This is not ideal. The issues of absorbing aromas and flavors arise. Even if you can avoid the aroma and flavor problem, the temperatures are too extreme at 0 to 40 degrees Fahrenheit.
Most producers dry their harvested coffee beans under the sun. This is cost effective since it doesn’t require any special equipment. At this stage of the coffee bean’s journey, being under bright light is exactly what they need. This process will take the moisture levels down from about 50 percent to 11 percent. At this point, however, the bean’s days under bright lights should be over. Additional exposure to direct sunlight will dry out the beans, thereby reducing flavor and aroma. Experts recommend storing green coffee beans in a dark place or in an opaque container.
The traditional burlap and jute sacks pose the biggest risk for pest infestations, especially if the beans are not dried to the recommended levels. Most pests need moisture to survive, so they are attracted to unroasted coffee beans. A coffee bean’s weight can be reduced by one-third within six months from coffee weevils. Coffee beans can also be infected with insects such as pesticides. These insects burrow their way into the coffee bean. Most of the shipments from developing countries are treated and certified as pest-free before shipping. Even if they arrive at a warehouse without stowaways, pests can find their way to the warehouse.
Lengthy storage times can lead to a qualitative and quantitative decline in the beans. The good news is that you can store green coffee up to twelve months without losing important flavor and aroma qualities – as long as you store it in a stable, cool, dark, and pest-free environment. If your coffee beans have come from Central or South America, Indonesia, or India, they will be 3 to 4 months old by the time you get them. If your beans originate in an African country, they can be 8 to 12 months old already by the time you get them. Make sure you factor these time frames into your storage plans.