Everything you need to know about coffee beans—and how to keep them fresh

To start the day fresh, many of us reach for the coffee maker of our choice: an espresso machine, a drip coffee maker, or a simple pour-over dripper. Regardless of how you like your coffee prepared, your coffee beans better be fresh, as there’s a noticeable difference between fresh beans ground just minutes before brewing and stale beans that have been sitting around.

However, chances are, you can’t restock your coffee supply by going to your trusted local establishment as regularly as you wish. Whether you’re stuck in one place for an extended period of time or you’re afraid of supplies running out, it doesn't hurt to know how to make sure the coffee beans stay fresh as long as possible.

What makes coffee beans go stale?

As much as humans need oxygen to survive, it can be deadly for coffee beans, along with light, heat, and humidity. Any agricultural product can spoil when neglected, and coffee beans are no exception—they dry out and become incredibly bitter and stale.

In coffee processing, the beans build up their depth of flavor, aroma, and other distinct flavor profiles mainly in the last stage: roasting. It’s also when decaying starts—the beans begin to “breathe out” carbon dioxide, which accelerates staling. The freshness of the beans will diminish as time goes on, which is why you should check the roasting date before making a purchase.

For a standard 12-ounce bag of beans, it’s recommended they be consumed within a month of the roasting date—which shouldn’t be a problem for most coffee drinkers because a 12-ounce bag typically yields about 20 cups of coffee. On average, coffee beans go stale within a few hours after grinding so it’s always a good idea to grind your beans right before brewing. It may sound a bit inconvenient to add the extra steps of measuring exactly what you need for a cup of coffee and grinding to the optimal fineness (or coarseness), but those steps definitely pay off.

Plus, if you’re an espresso drinker, the best espresso machine that we've tested actually has a built-in grinder that can do the work for you.

How to store coffee beans in the short-term

If you buy coffee directly from a roaster or a retailer, keep your coffee beans tightly closed in the original packaging and place the bag in the driest, coolest area in your house. Typically, there’s a “one-way” valve on the coffee bag, which allows the coffee beans to breathe out carbon dioxide while stopping oxygen from coming in.

If you like to use your own coffee jar to keep the uniform look of your kitchen, then try to make sure the jar is opaque. Light exposure can also expedite the oxidation process, which results in bad coffee.

How to store coffee beans in the long-term

If you buy coffee beans in bulk because it makes more economic and logistical sense, then finding the best way to store beans to ensure their integrity is crucial. As coffee beans are hygroscopic, which means they can readily take up moisture from the surrounding environment, storing them in an airtight container is necessary at all times.

If you decide to freeze some of the beans, be sure to divide up as much as you need for one (or two) weeks at a time. You can use a food vacuum sealer to make sure there’s no excessive oxygen in the bags that could potentially damage the coffee. If you don’t have a vacuum sealer, you can also simply use freezer-friendly Ziploc bags and push out the air before sealing them.

Note that the freezer solution is still not an ideal way to store coffee because drastic temperature changes can cause condensation on the surface of the coffee beans, resulting in the beans going stale. To bypass this obstacle, you can let the beans thaw in the bag when taken out of the freezer, so the condensation only accumulates on the exterior of the bag.

What’s absolutely beautiful about coffee is its potential—from fruity and floral, to nutty and smoky, coffee’s flavor profiles vary from one region to another as altitudes, climate, and roasting methods differ. Without fresh beans, the most nuanced tasting notes can’t be appreciated—which is what makes these techniques to maintain freshness so crucial.