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Does Coffee Go Bad If Left Out?

Rebecca Hanlon
Last Updated: February 28th, 2023

Have you ever made a cup of coffee and forgotten to drink it? Maybe you had to rush out to work or got caught up with other chores.

Whatever the reason you had to leave your coffee out, can you still drink that cup of coffee hours later or does coffee go bad if left out?

In this guide, we’ll talk about what happens to your brewed coffee after you make it and whether or not it goes bad.  Here’s everything you need to know.

What Happens To Your Brewed Coffee If It’s Left Out

brewed coffee left out

A cup of brewed coffee can still taste good for 30 minutes after making it. However, you can still drink your black coffee up to 24 hours after brewing it. But, you need to remember that it won’t taste as good as drinking it when it’s fresh.

For starters, your coffee will become stale. This is because of oxidation-a chemical reaction that takes place when your coffee’s aromatic compounds come into contact with oxygen. When oxidation happens, your coffee starts to lose its flavor.

This chemical reaction happens faster when your coffee remains in a hot area. This explains why cold coffee can preserve its flavor longer than a hot cup.

So, if you decide to let your coffee stay overnight, its flavor will continue to evaporate until it’s completely gone. While it’s still safe to drink it, the flavor and aroma of your cup are entirely different and tend to be more unpleasant than freshly brewed coffee.

On top of that, it’s important to note that if you leave out a cup of coffee for more than a few days, mold often starts to grow in it. This usually starts growing between four and seven days of being left out.

If you want your coffee to have the best taste and aroma, drink it right after brewing it. You could also pour it into an airtight container or a tumbler to slow the oxidation process.

Doing this will slow down the time it takes for your coffee’s aroma to dissipate.

How Leaving Out Your Coffee Affects the Caffeine Content

While the flavor and aroma of an old coffee will disappear, caffeine won’t. Caffeine is a stable compound and won’t degrade, even after hours of being left out.

In other words, the caffeine level of your coffee remains the same the entire time it’s left out. So, if you just need the caffeine kick to boost your energy, it’s alright to drink your untouched coffee after a day.

Leaving Out Coffee That Has Milk In It

leaving out coffee

While it’s okay to leave black coffee out for up to 24 hours, that’s not the case if your coffee has dairy products in it.

When your drink has dairy products in it, it’s safest to consume your latte or cappuccino within two hours after preparing it.

This is because when you allow milk to be left out at temperatures between 30 and 140ºF, bacteria begin to grow in it. This makes your now contaminated milky brew unsafe for you to drink.

If you enjoy drinking your coffee slowly, pour your drink into an insulated tumbler to keep a safe temperature.

Leaving Out Coffee Beans

leaving out coffee beans

You can leave your coffee beans for two weeks without noticing a change in their taste. But, even though the aroma and taste will change slightly, your beans will still taste good for up to 3 months.

The two-week period is mostly used by professional coffee drinkers who have developed coffee palates.

If you’re just someone who loves a cup of plain coffee, three months after the roast date is reasonable and won’t make a huge difference to the taste of your coffee.


Got questions like whether you can place coffee in the refrigerator or how to store your brewed coffee?

I’ve got you covered. Here are a few more frequently asked questions about leaving your coffee out.

How Long Can You Place Your Brewed Coffee in the Refrigerator?

Placing your brewed coffee inside your refrigerator can help slow down oxidation. This allows your coffee to stay safe longer. As long as it’s inside an airtight container, it can last for up to two weeks.

Does Cold Brew Coffee Go Bad if Left Out?

If you make a big batch of cold brew coffee, it will retain its flavor and aroma for up two weeks as long as you store it in a sealed container. This is enhanced if you leave it in the fridge, but it won’t go bad even if it’s left out on a counter.

Because the temperature of cold brew is lower, the oxidation process takes slower. The flavor and aroma won’t evaporate as fast as hot brewed coffee, causing it to go bad slower.

How Can You Safely Store Brewed Coffee?

It’s simple—don’t put any dairy in it. Store your coffee as a black brew in an airtight container and keep it in the fridge. This will help it stay fresh and prevent it from growing bacteria or mold.

Does Coffee Go Bad If Left Out – Final Thoughts

Even though your brewed coffee is safe to drink if you leave it out for a day, it’s still best to drink while it’s fresh and hot. It’s the perfect time to taste its best flavor profile while also preventing any kind of contamination.

And remember, if you add dairy to your coffee, drink it right away. You can leave it for at most 2 hours. Otherwise, throw it away.

You can also check out our other coffee guides that answer common questions like can you use coffee grounds twice or  can you use powdered sugar in coffee?

About The Author

Rebecca Hanlon

Rebecca has been a blogger for over 5 years, before that enjoying a number of jobs to fund her passion for travel. She's taught English as a foreign language, a part-time Barista, a waitress, and a tour guide.

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