If you come across an expired bag of coffee, you’ll likely fall into one of two camps. You’ll either toss it immediately because its shelf life has run its course or you’ll hang onto it thinking to yourself, “coffee can’t really go bad, so why waste it?” What you may not take into consideration is whether or not that expired coffee has retained any of its caffeine. After all, most of us don’t drink coffee just for the taste alone.
So does caffeine hang on in coffee beans or coffee grounds long after the expiration date or does it wither away as time goes by? The answer is a bit complicated. Long story short, the caffeine in coffee does lose its potency over time. It is, however, much more stable than the other elements in coffee, so there’s a chance that expired roast still has some caffeine in it. The real question is: should you drink it?
It can be a real shame to let coffee go to waste, but the idea of drinking coffee that’s well past its prime isn’t appealing either. There are a lot of factors that can impact the flavor, potency, and caffeine content of coffee. If you find yourself in this predicament, knowing all the facts can help you decide whether it’s worth keeping or whether it’s likely that you’d spit it out just as soon as it hit your lips.
What causes coffee to lose caffeine?
Unless you’re a serious coffee enthusiast, you may be surprised to learn that coffee begins losing many of its signature elements very rapidly once it has been roasted. Unroasted beans essentially have an unlimited shelf life and can retain their caffeine indefinitely. It’s the roasting process that sets off a cascade of reactions that cause the coffee beans’ flavor, aroma, and, eventually, caffeine content, to diminish.
When coffee beans are roasted, they lose the vast majority of their water content. This means the beans have lost a major preservative, which is what marks the beginning of their shelf life. It also causes the beans to become susceptible to external water sources, which can cause them to release their flavor and some caffeine.
While losing this water is more significant when it comes to loss of flavor and doesn’t have a huge impact on caffeine content, roasting does cause the bean’s caffeine to become unstable, which means it will fade over time, even if it does take a while. Keep this in mind when we go over how to store your coffee beans in just a bit.
Just as exposure to external water is a no-no for coffee beans, so is exposure to air. You can think of air as kind of sucking the life out of your coffee.
When in bean form, the coffee has a smaller surface area, which means it’s not being pummeled by air, and the effects won’t be as severe. However, when coffee is ground, all that bean dust is opened up to oxygen. From there, the oxygen will do what it does best and begin to degrade the coffee even further.
Even though it is crucial to processing coffee and eventually brewing it, heat is also an adversary of coffee. Even though we tend to think of darker roasts as being stronger, the heat it takes to reach that roast level can actually deteriorate the beans’ caffeine.
How long will caffeine last in coffee?
Given what we know about how a variety of elements impact caffeine, let’s get into exactly how long caffeine can or should last. Even with the impact of roasting and incidental exposure to air, caffeine can last at least four years in coffee.
This is far beyond the amount of time much flavor would still be hanging around. One important caveat, though, is that this timeline is dependent on the coffee being stored properly for the entirety of that time.
How to store coffee to retain its caffeine
As you may have come to realize, coffee beans are kind of needy! Storing them isn’t as simple as pouring them into a container and hoping for the best. These tips will help you learn how to store your coffee correctly to ensure it not only retains its caffeine, but its flavor and aroma as well.
Keep away from moisture
Remember when I told you to keep this in mind? Now that we’ve learned the impact external water can have on coffee beans, make sure you aren’t storing them near anything that might produce steam or anywhere that water may leak into.
Use an airtight container
You want your coffee exposed to air as little as possible. An airtight container will ensure that those beans are only exposed to oxygen when you open it up to scoop them out for a fresh brew.
Store them somewhere cool
We typically store our coffee in the kitchen, right? But kitchens tend to have a lot of appliances that produce heat. It’s best not to keep your coffee directly next to anything that’s going to be putting off heat, whether it’s a stove, toaster, or other appliance.
Should you drink expired coffee?
One of the biggest takeaways here is that, while coffee doesn’t necessarily go bad in the sense that it will start developing its own microbiome or make you sick, it really isn’t worth consuming after a certain point.
Whether or not the caffeine stays along for the ride, it still won’t be pleasurable to the palette. Caffeine is responsible for much of coffee’s bitter taste, so with much of the flavor gone, any remaining caffeine from expired coffee will just produce a brew that’s unpleasant from start to finish.
So yes, expired coffee will begin to lose its caffeine over time, it will just take much, much longer than it takes for that delicious flavor to start disappearing. And what you are left with, well… let’s be honest, it’s just going to be gross. Word to the wise, don’t drink expired coffee. Even if you’re desperate for the caffeine, there might not be any left anyway!