QUESTION: How long will my coffee stay fresh after the beans have been ground? What if I store them in a plastic container or in the freezer?. — Michael W.
ANSWER: The short answer to your first question is that coffee beans begin to lose their freshness immediately after they are ground. The best thing you can do is grind your coffee just before brewing. After just 15 minutes, your coffee will have lost 60 percent of its refreshing aroma (and scent is a large part of the taste experience).
Seriously, there’s no reason to fiddle with storage options like the freezer, refrigerator, or plastic food containers for your coffee once it’s ground. (We will tell you how to store your ground coffee if you don’t want to grind beans for every cup in a moment, though.)
It’s so quick and easy to grind coffee beans at home, and grinders are affordable. The delicious taste and aroma of truly fresh coffee is so worthwhile—there’s no reason to miss out. Grinding your own coffee beans also gives you a chance to customize the size of the grind to your coffee preparation method and the way you like your cup.
Why Does Coffee Lose Freshness So Quickly After Being Ground?
The oils that create the coffee flavor we love are locked inside the bean with a layer of protective covering. But once the beans are ground, this protective layer is compromised, and freshness begins to decrease for a few different reasons.
One of those reasons is oxidation, or the way the oxygen in our air changes the molecular structure of the ground coffee. As oxidation begins to change the compounds in the coffee into new molecules, the coffee’s flavor and scent start to go downhill. Because this process begins literally as soon as the beans are ground, we recommend only grinding the amount you need and grinding your coffee beans immediately before brewing.
The air isn’t the only thing that begins to change your coffee’s freshness once it’s ground. Just like brewing coffee in water releases the flavor of the coffee into the water, moisture in the environment can rob your coffee of some of its flavor. This happens because the oils in coffee are water soluble. Coffee can be affected by moisture in this way whether it has been ground or is still in its whole bean form, but the loss of flavor and freshness is much more severe when ground coffee is exposed to moisture, whether it’s liquid condensation or humidity in the air.
Carbon dioxide loss is another factor that explains why coffee begins to lose its freshness immediately after being ground. While the beans are roasting, they store carbon dioxide inside that helps move the soluble or volatile flavors in the coffee oils out of the beans and into the water. This carbon dioxide is lost very quickly after grinding—80 percent is lost within the first minute.
Now you understand that due to the work of oxygen, moisture, and air on your ground coffee, it’s best not to wait a moment to brew ground coffee. In just one minute, the flavor and freshness of your coffee has been drastically affected. But maybe you want to know how to store ground coffee in case you grind too much one day. Keep reading to find out how to store ground coffee and whole bean coffee, too.
What’s the Best Way to Store Coffee?
Although glass containers and Mason jars are cute, they’ll expose your ground or whole coffee beans to light, which begins to leach out their freshness and flavor.
You should also avoid exposing your stored coffee beans to air, moisture, and heat. Even storing your coffee too near the oven or keeping it in a spot that gets sunshine is not recommended.
The packaging that coffee comes in when you purchase it isn’t really designed to keep the beans as fresh as possible. The National Coffee Association says the best way to store your ground or whole coffee is in an airtight container that’s opaque (one you can’t see through), keeping the container at room temperature.
For best results, take your coffee beans out of the packaging they come in once you get your ground or whole bean coffee home from the store. Then move the coffee beans to your own storage containers. Of course, different types of packaging will keep your coffee fresh for different time spans. For example, a foil bag with a one-way valve (which can be a simple pinhole or a plastic valve) will keep coffee fresh for up to two weeks. Paper bags with no lining or thin lining are less trustworthy.
Should I Store Coffee in the Freezer or Refrigerator?
Just like coffee can absorb moisture from humid air, whole or ground coffee beans can absorb flavors and aromas from other foods in the freezer or refrigerator. Although both whole and ground beans are susceptible, ground beans will absorb much more. The result will be unpleasant tastes or smells in your cup of coffee.
You’ll see different opinions about storing coffee in the freezer or refrigerator, and many of those debates center around whether the coffee will absorb harmful moisture in storage. Those discussing moisture and refrigerator or freezer storage seem to have missed the possibility for the coffee to absorb flavors and smells from what’s around it.
Tips for Getting the Freshest Coffee
- Store your whole bean or ground coffee in opaque containers with an airtight seal, and keep them at room temperature in a dry spot. Another good storage option can be foil bags with one-way valves (plastic or pinhole).
- One way to ensure your coffee is always as fresh as it can be is to buy smaller containers of coffee more frequently. While you’ll have to shop for coffee more often, you’ll notice a difference if you are opening a new, smaller package every week or two.
- If you really want to use a clear container or a decorative one that is not airtight, try keeping most of your coffee stash in a recommended container instead, moving a small amount of coffee to the clear or decorative container as needed.
When green coffee beans are roasted, they lose enough moisture to make them impervious to mold. That means that, even though your coffee can definitely lose freshness or have its flavor altered, ground or whole bean coffee will never truly spoil or go bad. However, the expiration dates on packages indicate when the taste and scent of the coffee will be altered enough to taste stale or significantly affect your experience.