Ask ten coffee connoisseurs the best way to store and prepare coffee beans, and you’ll likely get ten different answers. Many people swear by their tried-and-true methods: freeze or don’t freeze, grind immediately, coarsely ground, finely ground, store in the store-bought foil bag, store in Tupperware, the list goes on.
Of course, whatever works for you, works for you. Carry on, coffee warrior. Just remember, coffee beans are much more sensitive than you might think. And here’s another piece of bad news: Understanding how and why coffee beans lose their freshness has a good deal to do with what you likely slept through in chemistry class. But fear not. We’ve pressed the grounds of coffee’s scientific properties to the bottom of the tumblr to present to you a smooth, rich cup of tips to inform you on proper storage of your beans.
Coffee can be understood as a series of chemical reactions taking place inside (and sometimes outside) the beans. It begins with the roast, when heat is applied to cause moisture to be released inside the green coffee beans. This also sets off other chemical activity, which is halted when a trained roaster sees the beans are at their desired level of roast. (Yes, “sees.” Coffee roasting is equal parts art and science.)
Coffee beans begin to lose their freshness almost immediately after roasting. Much like the car that depreciates the moment you drive it off the lot, the bag of whole bean you buy at the coffee shop or grocer has already come off its peak of freshness. Which means maintaining a fresh-brewed taste throughout the life of the bag requires attention to storage that reduces or eliminates exposure to elements, lest your already less-than-peak coffee go stale before you’ve had a chance to enjoy it thoroughly.
Go Bean, or Go Home
If freshness is important to you, you need to buy whole bean coffee. It’s that simple. Grinding accelerates the release of the desirable oils and flavors in coffee that will ideally land in your cup, so it’s important that you grind your coffee as close to brewing as possible. And here’s a little known tip: The size of the grind plays a role in determining the bitterness of the final product. Coarse grounds, in general, produce a milder flavor, whereas finely ground beans tend to produce more bitter notes.
The biggest enemy of your coffee’s freshness is oxygen. Oxidization in coffee beans will cause them to go south in a matter of days. That’s why it’s important for you to store your beans in an airtight container. Will the bag or canister in which the coffee was purchased suffice? Odds are, no. And frankly, very few of the storage containers you purchase at the store are truly airtight. Make sure you know what you’re buying.
Keeping your beans in the dark is another important safeguard. Light helps to trigger chemical reactions on the surface of the beans, breaking them down before their time. (Not to mention, if your beans are exposed to light, odds are they’re being exposed to oxygen as well.)
High and Dry
Similar to light, moisture will erode the quality of your coffee beans rather quickly. Coffee beans are hygroscopic, meaning they absorb and retain the moisture in the air they’re exposed to. Much like light and oxygen, this moisture will begin to trigger chemical reactions that will rob your coffee of the full flavor you’re after.
Since heat is used to trigger the release of chemicals at the roasting level, more heat applied to roasted beans will help carry on this activity. In fact, there are reactions going on inside the bean continuously after roasting. While you can’t stop this, you can dramatically slow them down by lowering the temperature around the bean.
The avoidance of heat, light, oxygen and high temps are what leads many people to believe freezing coffee beans is the preferable method of storage. That’s not inherently flawed thinking; however, you need to be extremely careful. Again, very few of the containers available at the store are truly airtight. If you choose the wrong container, you risk freezer burn. Moreover, you have to be quick. Opening your container of beans to scoop some out is a great way to invite condensation to form on them.
The best way to store coffee beans, and maximize freshness as long as possible, is to store a relatively small amount (about a week’s worth) in an opaque, airtight container, inside a cabinet that is not prone to temperature spikes. (The cabinet above your stove won’t due, nor will the one along the wall with direct sunlight in your home.) There you have it. All the chemistry, none of the class.