Yes and no. Coffee can go bad, but it doesn’t always go bad. It does, however, become unsuitable for consumption sooner or later. Whether that’s sooner or later depends entirely on how you’re storing the coffee, in what form you’re storing the coffee, and whether it’s come into contact with any reactive agents (oxygen, water, bacteria).
Like other foods, coffee is composed mostly of lipids and carbohydrates. Most of the carbohydrates in coffee are insoluble and indigestible. What you end up drinking is mostly water and the different lipids (oils) that give coffee its taste and flavor. In contact with too much moisture, coffee can attract and feed bacteria and fungi, causing mold and mildew. In contact with too much oxygen, the lipids become rancid and eventually dissipate. In bean form, it’s much harder for coffee to go bad and it will generally keep for months as long as you store it somewhere cool, dark, and dry. If kept in an air-tight container, your coffee will keep for much longer. Freezing can help keep it even longer, but you risk destroying the subtler flavor profile most coffees come with. If left out in the open or untouched for months, the beans will eventually lose all flavor and go completely stale. This happens faster in ground coffee, which is why it’s important to only grind as much coffee as you’re going to be consuming, or at least try not to grind more coffee than you’re likely to drink in 2-3 days.
When to Drink Coffee
Coffee is best consumed fresh. The closer the coffee is consumed to its roasting date, the better. As soon as coffee beans are roasted, packaged, and sent off, they’re already losing freshness. Start picking the right coffee beans, before anything else. If you don’t have a grinder, only ever buy enough ground coffee to consume in the next few days. Most companies sell coffee per pound or half-pound, so buy enough for 2-3 days before getting a fresh refill.
Some supermarkets store their ground coffee for months, meaning it can very well go stale. Try to only buy packages that have been vacuum-sealed and are completely airtight. It’s well-worth getting a burr grinder or blade grinder if you’re willing to invest a little bit for significantly better-tasting coffee.
If you’ve had your beans or grounds for a while, don’t just go ahead and brew them. Give them a sniff test first. If the beans or grounds smell bad or off, too sour, or slightly moldy, throw them into your garden compost, into your dirt, or into the trash. If there’s not much of a smell at all – if the coffee has gone “flat” – then chances are it won’t taste like much either. This coffee is useful as a cleaning abrasive or dyeing agent.
If the coffee has a rich coffee aroma, then you’re good to go. Coffee should always smell like coffee. If you grabbed your beans from out of the freezer, be sure to try and only grind as many beans as you’ll need for the day. Not only does freezing coffee beans change the coffee’s flavor profile, freezing the beans also means they become moist when thawed out and ground up, causing the resulting grinds to be a bit moister than completely dry grinds would be. This can drastically speed up the development of mold/mildew.
Since it’s nearly impossible to determine exactly how old any given bean is, it’s usually best to try and buy from smaller companies that are transparent about how and when they produce their coffee. If you live in a country where coffee is commonly produced and exported (India, Uganda, Ethiopia, South America, Southeast Asia), consider switching to local coffee, or better yet, find a farmer or farm business that cuts out the middleman and sells directly to its customers. Shop around, try different farms, and find the roast you like the most.
When buying coffee in bulk and storing it, be sure to keep it out of sunlight in a dry, dark, and cool place. Keep it away from any sources of moisture, light, or heat, and packaged tightly in (ideally) air-tight containers. Avoid freezing your coffee if you have the means or space to store it without excessive exposure to water, oxygen, or light, and only ever grind as much as you’re going to use in 2-3 days.
Even if you’re following each and every single one of these directions, it’s not a perfect system. Give coffee a whiff whenever you’re about to brew another batch, just to make sure that it actually smells like coffee, and not like mold/nothing.
Coffee theoretically stays drinkable for an eternity, as long as its stored properly. There have been cases of people opening tins of ground coffee older than they were and brewing themselves a cup. Although the results were less than impressive (often tasting more like ash or burnt cereal), it’s not likely to give you so much as a stomach ache, as long as the coffee is safely stored away from exposure to the elements.
Instant Coffee’s Shelf Life
Instant coffee keeps even longer, especially if frozen. While coffee beans last longest in a freezer (up to 9 months, usually, depending on the roast shade and when it was packaged/sold), instant coffee basically lasts forever in subzero temperatures. Unlike beans, instant coffee is already brewed, and only needs to be dissolved in warm water to finish a cup. This increases its longevity, one of the many reasons that sailors and soldiers have been relying on extracted coffee/coffee concentrate and instant coffees for as long as they’ve been around.
What to Do with Stale Coffee
If you’ve got coffee beans that don’t smell much like coffee anymore, there are still a handful of things you can do with them. Consider:
- Grinding them up and using them as an abrasive. This is perfect for scrubbing old pots and pans and getting gunk out of anything old and crusted.
- Seeping them in water to produce natural dyes. Grind them first, keep them in some water, and then use the resulting pigmented water to paint, dye clothes, or briefly dip some paper in it to immediately give it an aged look (great when planning treasure hunts for kids!).
- Keep the whole beans in a wide-lipped mason jar filled up about halfway, with a caramel or vanilla-scented tin candle on top. The heat will get the beans to relinquish some of their remaining final aroma, mixing with the candle’s oils and creating a delicious coffee atmosphere.
- Grind your coffee and place it in and around pots to ward off ants and other bugs and critters. Don’t do this if you have small animals or dogs/cats that are prone to curiously nibbling on anything in and around the garden. Beans might not taste very appetizing, but some pets have been known to put far less palatable things in their mouth.
- Use them in a compost heap or as fertilizer. This still works if your grounds aren’t just stale, but bad as well.
- Use coffee’s natural dye for furniture and wood, to give it a darker color without applying varnish. This won’t seal the wood, so it’s only recommended for heat-treated wood. Alternatively, apply on scratch marks on wooden furniture to mask the marks. This is especially useful if you have a clawed pet and plenty of wooden floors/chairs/sofas/beds.
Coffee can be used for a great many things, but its first and foremost use is always going to be to make a good damn pot of coffee. Even if you eventually intend to use it to make some soap or some scented candles, please don’t waste your coffee’s good flavor and beautiful aroma by storing it improperly and letting it go stale or bad. Keep it in a cool dark place, preferably in bean form, and consume it well before its date of expiry.