Are You Drinking Stale Coffee? Here’s An Easy Way To Tell.

Whether that coffee cup in your hand came from a local diner, a gas station or your high-end espresso-maker, all coffee is pretty good at getting the job done — meaning it can help you move through the world like an upright, sentient being, no matter how early in the day. But if you’re a true coffee connoisseur, you most likely want to enjoy that magic elixir when it’s at peak flavor and freshness.

Coffee beans, just like anything else you consume, can grow stale over time. That doesn’t necessarily mean your brew is unsafe or undrinkable as it ages, but it’s probably not going to be the Platonic ideal of a hot beverage. To keep beans at their peak for perking, check out these insights from coffee experts:

Old coffee is bad, but beans can sometimes be too fresh.

“The easiest way to explain freshness in coffee is to liken it to the ripeness arc of a banana,” said independent coffee consultant Erika Vonie. “Yes, you can eat a super hard, bright yellow banana, but it’s not as sweet and delicious as when it will be a few days later. … And yes, you can definitely eat a browning banana, but it won’t be the same experience as when it was at peak ripeness.”

Vonie said that coffee isn’t meant to be consumed right from the roaster, and that you should factor in the “off roast” time to know when it’s best.

“After roasting, the coffee ‘rests’ and releases gases built up from the roasting process,” she said. “There is a peak ‘off-roast’ date where the coffee is in its Goldilocks sweet spot, and that’s different for every coffee. As the coffee continues to age, it’ll still taste like coffee, but it may have more muted flavors and aromas.”

‘Best by’ isn’t necessarily ‘drink by.’

In the world of coffee, good things come to those who wait — though too long of a delay won’t yield ideal results.

“Freshness is a moving target, and it has different importance for different people,” said Kay Cheon, who manages wholesale and education at Dune Coffee Roasters in Santa Barbara, California.

“For a roaster, we might want to get coffee into someone’s hands as expeditiously as possible, but we might also want that person drinking the coffee to know that they’ll be getting the best results in the cup a week after it’s been roasted.

“For someone purchasing coffee, they might just want to drink the coffee straightaway, and might not even notice the same improvements from letting coffee rest or be able to have that be an option with their purchasing.”

Coffee expert James Hoffmann, a co-founder of the U.K.-based Square Mile Coffee Roasters, explained it this way: “Coffee is shelf-stable for a really long time. It’s perfectly safe to drink coffee a couple of years after it was roasted, but it absolutely will not taste its best then. But it’s a good idea to let the coffee rest for a week or so, up to maybe two, then use it within a month or maybe six weeks.”

He added, “What’s confusing about coffee is the presence of CO2 locked inside the coffee,” noting that “this escapes over time, and coffee people will refer to this as ‘degassing.’”

With that in mind, there’s a simple way to find out if your whole beans are really fresh. Put a half-cup of beans into a zip-close bag, squeeze out the air, seal the bag and leave it overnight. Fresh beans will release carbon dioxide and make the bag puff up. Stale beans will leave the bag flat.

Oil plays a role in coffee’s freshness.

A bean’s journey from unroasted to stale has some steps along the way, Hoffmann said.

“As the beans age, there’s a loss of aromatic compounds. And once they’ve escaped, you won’t be able enjoy them in your cup,” he said. “Then there are negative flavors created by oxidation from oil in the coffee bean, which will turn rancid over time.”

The darkness of the roast plays a big part in how much of that oil will be forced to the surface of the bean.

“You’ll see that darker roasts generally have an oily sheen to them,” Hoffmann said. “This oil tends to oxidize much faster, and the roasting process actually makes the whole bean more porous and less dense, so all the staling chemistry happens faster with darker roasts.”

Whole beans, not ground, stay fresh longer.

In addition to the roast, experts highlighted another factor that’s important for how coffee ages.

“Once coffee is ground, staling happens very rapidly,” Hoffmann said. “Most people can spot the difference between freshly ground coffee and coffee that was ground even just a day or two before.”

Cheon pointed out that quicker staling with ground coffee isn’t always a bad thing.

“If you’re going camping and don’t have access to a grinder, or if your coffee is particularly fresh, you can artificially accelerate the resting process by pre-grinding your coffee 30 minutes before brewing, instead of waiting a week for that coffee to rest,” he said.

For those wanting the freshest coffee possible, Hoffmann had a tip: “A good coffee grinder for your mornings is the best investment you can make.”

Here’s how to store coffee to preserve freshness.

Official word on proper storage comes from Mark Corey, the head of science and policy for the National Coffee Association, an industry group.

“We generally recommend storing coffee beans in a cool, dark location, ideally in an opaque, airtight container,” he said.

Vonie, the independent consultant, suggested keeping coffee in the same packaging it came in. “If you want to transfer it to a different container, make sure it blocks light and has an airtight seal,” she said.

Do you really need to freeze coffee? Cheon weighed in: “For certain coffees, I’ll vacuum-seal them or place them in sealed tubes inside of a dedicated coffee freezer. But for those most part, especially if you’re drinking coffee regularly, the best practice is simply keeping it away from heat, moisture and sunlight.”