It all started when I moved into my dorm right across from a Dunkin' Donuts with a $1 happy hour. I hated coffee until my friends and I started going to Dunkin' during finals week. Then, my friend got me a coffee maker. My small delight with coffee turned into a full-blown addiction. When the machine broke, It got to the point where I was so desperate for coffee that I took apart the machine to fix it myself. I was hooked ... but it took me a while to finish one bag of coffee and once I did get to the end of it, I swear it tasted different than when I first opened. It made me wonder, does coffee go bad?

Does coffee go bad?

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The answer to that question is a little complicated because when coffee "goes bad" it's much different from any other food going bad. It won't harm you at all. You could be drinking bad coffee right now and not even know it.

Coffee going bad just means the grinds no longer produce coffee that taste as good as when the bag was opened. Bad coffee tastes flat, bland, and old. It's like coffee from the large jar in the office that you swear has been there since you started working there, and it tastes like someone is trying to slowly poison you, but it's not poison. 

On the other hand, if your coffee smells weird and tastes sour, it's probably being stored wrong and is growing mold. You can tell if you see puffy white mold on your coffee grinds or your coffee is starting to taste more like rotten milk or sour fruits than coffee. Don't go near that. Throw it out immediately. Spit that out.  

How to tell if coffee's gone bad

First is the smell. If the grinds themselves don't really smell like coffee anymore, or like anything, when you open the bag, they've gone bad. Ideally, you want to be able to instantly smell the coffee, as if you had just opened it. 

Second is the taste. If you've ever gotten a regular hot or iced coffee from Starbucks, you can taste the distinct and strong coffee flavor. If your coffee doesn't have that fresh and bold flavor, then it has gone bad. 

How long does coffee last?

This is the million-dollar question. If you look this up on the internet, you'll get a bunch of answers on how long coffee lasts and how to properly store it. That is why I found the closest expert, Starbucks Barista Jon-Paul Virella (or the Coffee Master, as Starbucks would call him), to answer all of my questions. Coffee Masters at Starbucks have to go through extra training and testing to earn the title Coffee Master. When they complete the training, they earn a black apron. If you have any questions at Starbucks, anyone with a black apron should always know the answer. 

According to Virella, grinds start degrading once the bag is opened and have a short shelf life. They're affected by light, humidity and temperature. This is why you should store coffee beans and grinds in a dark, room temperature place with low humidity. 

Ground coffee is the first to go bad. Coffee grinds only last one day. "If you're looking for a good cup of coffee, grind [the beans] yourself." says Virella. He recommends getting a bag of whole, unground coffee beans because  coffee beans last a week once opened. On the other hand, an unopened bag of coffee will last six month after roasting. If you want coffee that is always fresh, get packages of instant coffee because each packet is one cup of coffee and unopened bags never go bad.

These are the Starbucks standards, but ... 

Let's be real...

We're in college here. We do not go through one whole bag of coffee in a week and most of us don't even grind the coffee ourselves. So how long before we notice it goes bad? 

Again, the answer is up for debate, but the closer you are to the roasting date (not the expiration date), the better. From that point on it's best to rely on your senses. If your coffee still smells and tastes good to you, then go for it. Who am I to stop you? I usually stick to drinking coffee from a bag that's been opened for less than one month, but I also have a bag of Starbucks' holiday coffee from last year because it has vague cinnamon flavors and I have low standards. Use your judgement. 

How can I make coffee last longer?

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Shelby Cohron

It's 4 am and you're studying for another final while still drinking coffee because sleep is for the weak (note: that was a joke. Sleep is necessary and recommended by every doctor ever). The coffee you're drinking is stale as hell, but you keep drinking for survival. If only that coffee could taste better. 

According to Virella, don't freeze your coffee. The change in temperature lessens the flavor, especially if you keep taking the bag of coffee out of the freezer to make more coffee. It's like a temperature roller coaster for your coffee. Also, don't microwave your coffee if you want to keep the optimum flavor. To me, coffee that's been reheated tastes like it's been poisoned or someone added sugar-free creamer when I wasn't looking. 

Like I said before, coffee grinds are affected by light, humidity, and temperature. The best way to keep your coffee good for as long as possible is to keep it in a dark container with little humidity and at room temperature. Some people think that putting the beans or grinds into an airtight container like a mason jar will slow down the oxidation process, but there's no actual proof of that. 

Another method you can use to keep coffee longer is to cold brew your coffee. Once you notice your coffee is starting to lose flavor, cold brew it (for 20 hours) to get a concentrated taste that will last up to five days, according to the Coffee Master Jon-Paul Virella. Here's how to make DIY cold brew coffee, in case you don't know where to start.

What do I do once my coffee goes bad?

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Bernard Wen

Once your coffee goes bad, you could just throw it out, but there are also other things you can do so that it doesn't go to waste, such as baking with it or using coffee grinds as fertilizer for a garden or a composting bin. Baking with coffee works with "bad coffee" because you just need the coffee flavor.

Here are some recipes that will help your coffee craving, which includes a recipe for chocolate donut ice cream sandwiches. If you need more ideas, here are 19 creative ways to cook with coffee, and one of those ideas is a DIY coffee liqueur recipe. If neither of those options seems good, then you can also make a classic tiramisu, flan with coffee, or chocolate-covered coffee spoons that double as a treat and simple gift.

So ... does coffee go bad? Yes, but it's still drinkable and if you need something to keep you awake at an odd hour, "bad coffee" might be your best answer.