For the best coffee, buy fresh beans.

You coffee beans look about the same after they sit a few weeks on your countertop in a paper bag. But even though the beans look fine, their flavor has been ruined. The same thing happens if they are in a plastic bin at the grocery store, or if they were not properly packaged after roasting.

Buying the freshest beans is one of the most important factors in producing the best cup of coffee. The freshness clock starts ticking as soon as your beans are brewed. You want to buy beans that were roasted recently, and then properly packaged immediately afterwards.

Keeping Coffee Beans Fresh

To understand how roasted coffee beans must be kept fresh, it helps to understand the roasting process.  As beans roast they undergo chemical changes that release carbon dioxide gas (CO₂) even after the roasting stops. If the roasted beans contact oxygen in the air, first their subtle flavor will dissipate and then the beans go stale. The obvious answer is to place the beans into a sealed, airtight bag. That protects the beans from oxygen but the bag will rupture from the CO₂ gasses that continue building pressure inside the bag.  That's why placing beans into a tightly sealed container immediately after roasting will not work.

Until the 1960s, the solution was to degass coffee before packaging it, by storing roasted coffee in a controlled environment until the CO₂ had been fully released. Then the roasted coffee would be flushed with nitrogen and either packed into a sealed bag or packaged in a vacuum. Unfortunately, the beans were stale after the degassing finished.

Today's Coffee Packaging Uses One-Way Valve

In the 1960's, the degassing valve was invented, which allowed for roasted coffee to be packaged immediately. A degassing valve is the small one-way valve that allows gasses and pressure inside the package to be released without letting oxygen in. This valve allowed freshly roasted coffee to be packaged and shipped, and is the basis for the gourmet specialty coffee beans we enjoy today.

The other enemy of your beans is moisture. Water vapors in the air will attack your beans. That is also why you should never store your beans in a refrigerator because the air in a refrigerator contains more moisture.

You can put beans into a freezer but only once. If you bring the beans out of the freezer and let them thaw, then re-freezing will increase the water content and ruin the flavor of hte coffee beans.

Keep your beans in a cool dark place, in an airtight container and they will stay fresher longer for a better cup of coffee.

Remember that freshness matters after roasting. Green beans are very stable and under the right conditions can keep for years before they are roasted. But once your coffee beens have been roasted, then they start losing the flavorful oils to the air and moisture unless properly packaged and stored.

Back to Choosing the Best Gourmet Coffee Beans