How Long Does Coffee Last After You've Brewed It? - HomeGrounds

How Long Does Coffee Last, And Can It Go Bad?

Have you ever wondered how long coffee lasts? The first time I had day-old coffee from a murky pot I couldn’t help but wonder the same thing. Coffee made in the morning and left to sit is a common sight in many workplaces and old-school diners. Any coffee lover who’s tried it probably remembers the taste, and not fondly.

Common sense dictates that brewed coffee doesn’t stay good forever. But when exactly does it go bad, and why? Is old coffee dangerous for your health or just less delicious? Let’s find out.

How Long Is Coffee Good For?

Coffee is good for a certain time after which it goes bad. It goes bad at a different rate depending on its preparation method. Here’s what you can expect from every style of coffee.

• Green coffee beans: Home roasters will be happy to know that green coffee beans last the longest. You can store them for 6 to 12 months without losing flavor.
• Roasted whole coffee beans: Most roasters give their beans a one-year expiry date, but the coffee starts to taste stale after about a month.
• Pre-ground coffee: Ground coffee loses its taste and aroma much faster than whole beans. Ideally, you should grind right before brewing. But if you’re buying ground beans, try to use them within a week.
• Instant coffee: Instant coffee can stay “good” for years, probably because it isn’t that good to begin with. Sealed containers of instant coffee can last for a decade or more, and even once open, expect a year or two from your instant grounds.
• Coffee pods: Coffee pods are airtight, so they should maintain their flavor for a few months. However, it depends on how fresh the ground coffee was when it was sealed in the pod.
• Brewed coffee: Brewed coffee is at its peak freshness for about 30 minutes, but it stays good for up to 12 hours. The trouble is that it’s difficult to reheat black coffee without ruining its flavor. A hot plate is bad; the microwave is worse. If you aren’t drinking your coffee immediately, use an insulated thermos or thermal carafe.
• Cold brew: Cold brew concentrate will last up to two weeks in the fridge, though you’ll notice the flavor start to degrade after week one. Canned cold brew at the grocery store is good for about 6 months.

Does coffee go bad?

Yes, coffee sitting out can go bad. But bad coffee isn’t unsafe; it won’t make you sick. It just won’t taste very good (1).

“Coffee…does go out of date, but doesn’t mean that you’re going to get sick. It’s going to lose the freshness, flavour, and aromas.”

The exception is brewed coffee with milk or creamer added, which can make you sick if not consumed within two hours.

Different types of coffee go bad in different ways. Whole bean, pre-ground, and instant coffee get stale. They don’t taste unpleasant so much as they just don’t taste. Brewed coffee, both hot and cold, can develop an off taste or aroma when left for too long. There is no scientific evidence that it will make you sick, but it might have a rancid or rotten flavor.

Is It Bad to Drink Day Old Coffee?

You can drink coffee a day old, but we don’t recommend it, especially if it has acquired an unpleasant smell and/or taste. It won’t make you sick, but it could start your morning off on a sour note. Definitely do not drink day-old coffee if it has milk in it, even if it’s non-dairy milk.

Factors That Impact How Long A Coffee Stays Good

The main factors limiting coffee shelf life are the ones that speed up the oxidation process:

• oxygen
• light
• heat
• moisture

You want to minimize exposure to these conditions as much as possible to keep coffee beans fresh as long as possible.

Roast level also plays a role. Dark roasts are roasted for longer, meaning the bean structure suffers more damage; they are more porous. That makes it easier for the beans to oxidize, so dark roasts go stale faster. However, dark roasts have bolder flavors to begin with, so you may not notice the flavor loss as quickly as with a lighter roast.

How To Tell If Your Coffee Has Gone Bad

Your nose is the best way to check if brewed coffee has gone bad because it probably won’t look any different. If it smells rotten or rancid, chuck it out. If it smells fine, give it a taste. If it tastes bland, bitter, or just plain bad, it’s probably past its prime.

When assessing whole bean or pre-ground coffee, first look for a “Roasted On” date. A coffee is freshest within the first month of roasting. If the roasting date isn’t listed, check for an expiry date. Most roasters choose the expiry date as one year after roasting – though the coffee will be noticeably stale long before that.

You can also assess pre-ground or whole bean coffee by smell, but in this case, you’re looking for the opposite of the brewed coffee. Old coffee grounds aren’t characterized by a rotten smell but by an absence of scent.

Understanding The Shelf Life Of Coffee

Coffee degrades due to contact with oxygen, a process called oxidation. Essentially, this is the same thing that happens to apples when you slice them open and leave them for a while (2).

Although oxidation isn’t visible to the eye in the case of fresh coffee beans, it has a significant impact on the coffee taste. Oxidation causes the flavor compounds in the coffee to deteriorate and be released into the air. If you make coffee using old coffee beans or ground coffee, it will taste stale and bland.

Once the beans are ground, they oxidize more quickly (3). This is because grinding coffee dramatically increases its surface area – by over 10,000 times in the case of a fine espresso grind – exposing much more of the bean to air.

Why Does Coffee Turn Bitter?

Oxidation doesn’t stop once your coffee is brewed; after all, water also contains oxygen. As coffee sits, the ongoing reaction raises the pH level, making it taste bitter. This is why you should never let your coffee sit in a brewing pot for longer than necessary.

Proper Storage Methods Of Ground Coffee And Coffee Beans

The best way to store coffee is an airtight container that keeps your coffee from exposure to air, light, heat, and moisture. Ideally, you shouldn’t buy a bigger bag of coffee than you can drink in a week or two. But if you prefer to buy in bulk, ensure coffee is stored properly to give it a long shelf life.

Quality coffee storage canisters have a basic pumping system to remove air and an opaque case to block light. Store coffee beans in a cabinet rather than the countertop as it will likely be cooler and less humid.

Should you freeze coffee beans?

Freezing extra coffee beans is an acceptable solution for long-term storage, though not as good as regularly buying freshly roasted coffee beans. Ensure the coffee is sealed in an airtight container because porous coffee beans easily absorb other flavors and aromas from your freezer. 

Coffee beans will stay fresh for up to 6 months in the freezer. The most important thing is to freeze your coffee only once. Once you take it out of the freezer, don’t put it back in. The freeze-thaw cycle is the enemy of good flavor.

Final Thoughts

The time coffee is good for drinking safely depends on the method you used to brew it and how you stored it afterwards. Coffee doesn’t go bad in a way that makes you sick, but it definitely loses flavor when it’s past its prime. To ensure your coffee always tastes great, buy fresh whole coffee beans and grind them just before brewing. Drink brewed coffee in the first 30 minutes. Keep coffee beans or coffee grounds in a coffee canister, or store your coffee in the freezer for the long-term.

With these tips, you’ll never have to gulp down a cup of stale coffee again. Enjoy!

Got any more questions about the best way to keep coffee fresh? Let me know in the comments!

FAQs

How long will coffee last in a thermos?

Coffee will last for up to 10-12 hours in a high-quality thermos or 4-6 hours in a basic insulated thermos. It can technically last longer than that, but don’t expect it to be hot. If you have milk or creamer in your coffee, drink it within a few hours. If in doubt, check that the temperature is above 140 F to be food-safe.

How long does coffee last in your system?

Coffee lasts in your system for about 10 hours, depending on your tolerance and physiology. After you drink a cup of coffee, the caffeine impact peaks within the first hour. After 6 hours, half the caffeine remains in your body. After 10 hours, most people will no longer feel any caffeine effects.

How long will coffee last in the fridge?

You can keep brewed coffee in the fridge for up to a week, either hot coffee or cold brew, but it will not taste or smell as good as a freshly brewed cup. Make sure to cover your cup or carafe to avoid absorbing the aroma of other foods or beverages inside the fridge.

References

1. Brown, H. (2020, April 15). How to Store Coffee at Home. Retrieved from https://perfectdailygrind.com/2020/04/how-to-store-coffee-at-home/
2. McLandsborough, L. (2007, July 30). Why do apple slices turn brown after being cut? Retrieved from https://www.scientificamerican.com/article/experts-why-cut-apples-turn-brown/
3. Roth, K. (2010, May 13). Espresso – A Three-Step Preparation. Retrieved from https://www.chemistryviews.org/details/ezine/694285/Espresso__A_Three-Step_Preparation/