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The short answer is: yes, coffee grounds do go bad. But don’t go running off satisfied with your answer, because there’s a lot more to this story.
Here’s just a brief list of the questions I’ll be tackling in this article:
How long do coffee beans last? Do coffee grounds go bad if you freeze them? Do coffee beans go bad as fast as coffee grounds? What makes coffee go bad? Can you drink expired coffee? Are fresh-ground coffee beans better?
So if you came here just to ask “Does coffee go bad” or, more specifically, “Do coffee grounds go bad?”, you can go on your way. If, on the other hand, you want to understand how coffee grounds go bad, how you can store them to keep them fresh longer, and even more exciting topics about coffee storage and freshness, you are in the right place.
Grab a fresh cup of coffee, and let’s jump right in.
What Makes Coffee Go Bad?
Ever wondered why coffee containers often say “store in a cool, dry place”. Or why they are vacuum-sealed? Turns out, there are good reasons for all of that. Oxygen, light, heat, and moisture are the main reasons that coffee goes bad.
Pretty much everything in your pantry is prone to oxidation. Oxygen makes lipids (fats) go sour. It makes carbs get musty. Coffee is no exception, and exposure to oxygen is often the biggest culprit in coffee staleness.
Sunlight and artificial lights will cause a breakdown of the aromatics in the coffee into more bitter compounds, a process known as photodegradation.
The decay processes we’ve already talked about (and almost all other chemical reactions) happen faster at higher temperatures. Just think about it: Why do standard brewing methods work faster than cold brewing? The heat speeds up the process.
Beans last as long as they do because they are a dry good. When too much moisture gets in, they become a breeding ground for bacteria and mold. As you can imagine, that increases the risks quite a bit.
Which Lasts Longer: Ground Coffee vs Whole Bean?
Oxygen and light react with coffee when they hit its surface. The more surface there is, the faster the reaction occurs and the faster the coffee goes stale.
Which has more surface area: coffee beans or grounds?
Grounds have much more surface area than coffee beans. The finer the grind, the more surface area they’ll have. An espresso grind can have 50-100 times the surface area of an equivalent weight of coffee beans.
Your best way to keep coffee fresh is to buy whole bean coffee instead of grounds. Then grind your coffee beans as you need them, preferably keeping the grounds themselves only for a day or so.
How Long Do Coffee Beans Last?
Once they are roasted, coffee beans start to go stale immediately. They are only at optimal freshness for about 2-3 weeks. After that point, the flavor profile of the coffee will change, and you’ll notice more bitterness in place of any complexity or delicate flavors the beans originally held. This is many of the best coffee roasters ship freshly roasted coffee beans only, ensuring that you’ll have several days to enjoy your beans before they become significantly stale.
Okay, But Does Coffee Expire?
Although the flavor changes quickly, older beans are still generally safe to use as long as they have been kept dry. Under normal conditions, it takes somewhere between nine months and ten years for coffee beans to start growing mold, making them unsafe to consume.
There are factors that can cause coffee to expire sooner, though.
The biggest factor is moisture. If the beans aren’t kept dry, that 9-month lifespan can drop to a matter of weeks or even less.
The second factor is the oiliness of the beans. Even without moisture, surface oils can provide a breeding ground for mold. Most beans don’t have enough oil for this to matter, but some extra oily roasts will expire faster for this reason.
And let’s not forget that oils also go rancid over time, a process that results in rancid coffee, arguably a worse flavor issue than stale coffee. In general, oily coffee beans just don’t last as long as less oily beans.
How Long Does Ground Coffee Last?
By the time you buy it, pre-ground coffee is probably already stale. Sorry, I wish I had better news. Fresh ground coffee only remains at peak freshness for about 30 minutes.
Do coffee grounds go bad that fast?
Just like with coffee beans, you can still consume grounds after their peak freshness. However, the flavor will go from complex and aromatic to bitter much more rapidly.
Any amount of moisture will also impact the grounds faster because of the extra surface area. Beans that are a year old are probably safe, but I wouldn’t touch year-old coffee grounds. The upper limit is closer to 2-6 months. After that, it’s not worth it — just throw them away.
Are you starting to see why I recommend buying whole beans instead of grounds?
Can ground coffee go rancid?
It absolutely can, especially if the coffee beans it came from were extra oily. Take a whiff of the grounds and see if they smell sour or otherwise unpleasant. If they do, you probably want to just throw them away — nobody likes rancid coffee.
Does Brewed Coffee Go Bad?
I’ve described moisture as the primary enemy, so you might assume that brewed coffee would be different. After all, it’s already had moisture added. And, it turns out that’s exactly right. Your coffee will oxidize faster in liquid form than it did when it was just beans.
How long does coffee last?
Once you brew coffee, you have about 4-6 hours of optimal flavor, and about a day before you should definitely dump it. If you refrigerate your fresh coffee, you can increase its lifetime to about 3-4 days. You can, of course, reheat coffee during that time, but every time you reheat it you’ll be breaking down more of the oils and aromatics, changing the flavor of your drink. You are much better off keeping your coffee fresh and hot in a thermos or heated mug instead.
What About Storing Instant Coffee?
Despite its look, instant coffee is nothing like ground coffee. Instant coffee is essentially brewed coffee that has been dried into a powder. This important difference is a game-changer for maintaining freshness. Instant coffee can stay fresh for 12-18 months after it is opened, and it is safe to consume for as much as 20 years!
All of that is assuming you keep moisture away. Just like with grounds and beans, instant coffee will go bad faster if moisture gets in. After all, instant coffee with moisture is, well, coffee.
Do K-Cups Go Bad?
If you know how Keurigs work, you know that K-cups are filled with coffee grounds. You would assume this means that they would go bad very quickly, just like other grounds. But k-cups are individually vacuum-sealed, which greatly extends their shelf life. You can expect them to last for about as long as coffee beans.
Other coffee pods go bad at a similar rate if they are properly sealed. However, some brands do not seal their pods as well as Keurig, so theirs could go fast almost as quickly as coffee grounds. If the seal on your k-cups is broken, they will also expire at a rapid rate and should be used within a day or two.
How To Tell if Coffee Is Rancid or Bad
How can you tell if your coffee beans or grounds have gone bad? A quick sniff is your best early indicator. If the beans smell even the slightest bit rancid, moldy, or mildewy, it’s time to get rid of them. Trust me, it only gets worse from there, and it’s not worth your health just to get one more pot of terrible-tasting coffee out of them.
You can also do a visual inspection. Look for any sign of mold or mildew on the beans. You likely won’t notice anything if it passed the smell check, but it never hurts to be sure.
How can you tell if ground coffee has gone bad?
Your smell test is probably all you have to rely on here. Visual checks can be tougher unless there is mold growing right on top of the grounds. Because grounds expire so much faster, you should be extra careful to check, and I strongly suggest an “if in doubt, toss it out” philosophy.
Can Old Coffee Make You Sick?
Stale coffee will not make you sick. Even rancid coffee won’t immediately make you sick, although ingesting rancid fats over time can lead to health issues.
The real risk factors are mold and mildew. Once there are any hints of mold or mildew on the beans or grounds, coffee is definitely not safe to drink. Just throw it away.
How Can I Keep My Coffee Fresh?
There are steps you can take to make your coffee last longer. I’ve hinted at some of these already, but let’s walk through them all now.
Buy whole beans
Are fresh ground coffee beans better? Yes, they most certainly are. If there is one message I want to get across, it’s that fresh ground coffee is a game-changer. Buy whole beans, store them as whole beans, and only grind them as you need them, no more than a day in advance. You’ll thank me later.
Store your coffee in a cool, dark, dry place
Heat, light, and moisture are the enemy. Fortunately, most pantries or cabinets are perfectly fine places for dry good storage, including storing coffee. If you don’t have a dark, cool pantry, you can make up for it with a good enough storage container (see below). However, you should be extra careful about any storage area that isn’t completely dry.
Store your coffee in the right container
Light and oxygen are the biggest culprits, so let’s cut them out as much as possible. Some coffee storage containers are dark and vacuum-sealed, and that is your best bet if you want the beans to last for months.
Tinted containers are better than fully transparent, which is why the best coffee grinders tend to use tinted hoppers and grounds bins. This is fine for a few hours or even a day or two, but even this much exposure to light is problematic beyond that.
Definitely don’t use containers that are open to the air, but most beans come in containers that are resealable enough for a few days or even a couple of weeks. Beyond that, you should definitely invest in an airtight container.
Can You Freeze Coffee Beans?
Freezing is one of the most popular, and often one of the best, ways of extending the life of foods. So it’s naturally one of many people’s go-to ideas for making coffee last longer.
So can you freeze coffee beans (or ground coffee)?
You can, but I strongly recommend that you don’t. Freezing extends the shelf life of your coffee beans or coffee grounds by several months to even a few years.
However, you are sacrificing nearly all of the flavor of your coffee in the process.
When you put foods in your freezer, moisture tends to seep in and form ice crystals. When your coffee freezes, this moisture is absolutely brutal to it, turning even the most intense coffee beans into sources of bland brown liquid. I’m not even going to try to make it sound more appealing, because it isn’t.
Can You Freeze Brewed Coffee?
Absolutely! Since moisture is no longer an issue, you can definitely freeze your already brewed coffee. In fact, pouring it into ice trays can make for fun coffee cubes that can be used in a variety of beverages. They are one of the best ways to avoid diluting the flavor of your iced coffee with regular ice cubes.
A Few Final Words
Fresher coffee tastes better. That’s the overarching message here. One of the biggest differences between low-quality coffee beans and some of the highest quality espresso beans is how long they’ve been lying on a shelf before you buy them.
Few people get sick from old coffee beans or grounds because the smell of mold and mildew will usually drive you away from dangerously old coffee. But that doesn’t mean you are enjoying your best coffee experience. If you are buying pre-ground beans, storing your coffee incorrectly, or leaving it in the pantry too long, you may be missing out on the best flavors that your coffee has to offer.
Did I answer all of your questions about coffee freshness and storage? If not, drop your questions in the comments, and I’ll add them to the article. Your feedback is what makes this blog work, and it’s always appreciated. Now go drink some freshly roasted coffee.