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Can You Drink Day Old Coffee?

It’s late afternoon, but you make a full pot of coffee. With all the items on your to-do list, you’ll easily drink the entire thing. Right?

Cut to next morning. You’re staring at half a pot of day-old coffee. Should you drink it or throw it out?

Whether you’re concerned about safety or flavor, keep reading. In this article, I’ll give you the lowdown on day-old coffee.

aged black coffee

Is Day Old Coffee Safe to Drink?

The short answer is yes. Day-old coffee is safe to drink if it’s black. 

It takes a few days for bacteria and mold growing in brewed coffee to reach harmful levels. Plain coffee can sit at room temperature for several hours to a few days without turning toxic. 

The situation changes once you add things to your coffee. When cream, sugar, or syrups break down, they speed up harmful bacteria growth. If you add any of these to your coffee, it’s best not to drink it after it has sat out for a day.

Why Does Day Old Coffee Taste Bad?

Day-old coffee is safe to drink. But whether you want to drink it is a different question entirely. 

When a cup of coffee sits out for an extended period, it goes through flavor changes and may taste bitter. This change is due to oxidation

Oxidation, along with bacteria growth, is what causes food to rot. It would take a long time for coffee to oxidize to the point of being poisonous. But even a few hours can be enough to change the flavor of your brew. 

As soon as beans complete the roasting process, they oxidize if exposed to oxygen. Heat also increases oxidation. 

To some extent, this chemical reaction is unavoidable. Oxidation occurs even as the coffee maker brews the beverage. 

When a freshly brewed cup of coffee oxidizes, the natural flavor compounds break down. This chemical change creates an unpleasant acerbic taste, and unpleasant taste compared.

Reducing the time your coffee has to oxidize is the key to a quality cup. Storing and refrigerating the coffee in an air-tight container will also slow oxidation. 

That said, reheating coffee breaks down flavor compounds even faster. So consider making old coffee cold coffee.

aged moka pot

Does Coffee Need To Be Refrigerated?

You don’t have to refrigerate coffee brewed in a regular coffee maker. But refrigeration can help prevent bacteria growth and oxidation. 

At room temperature, the brew will start to go bad within a couple of days. If you refrigerate leftover coffee, use an air-tight container such as a thermal carafe

Refrigerating slows down the growth of harmful bacteria. It also reduces the rate of oxidation.

Drinking Day Old Coffee: Tips

My vote will always be for a fresh pot. But if you decide to drink day-old coffee, there are a few things you can do to make the experience tastier. Here are my tips. 

Refrigerate It When Brewed

If you plan on drinking coffee a few days after brewing it, you’ll definitely want to refrigerate it. Refrigeration slows oxidation and bacteria growth, keeping the coffee safer and tasty. 

Try to refrigerate the liquid immediately after brewing. The longer the liquid is hot, the higher the potential for oxidation and flavor impact.

black coffee in cups

Drink Cold Over Ice

If you’ve left your coffee out and it’s gotten cold, you may have considered reheating it. My recommendation? Don’t. 

Reheating coffee further changes its chemical structure. This chemical reaction degrades the flavor profile. Microwaving is particularly bad for taste. But even if you use a stove, reheating reorganizes the chemical makeup. 

Instead, try enjoying your cup over ice. Cold brew is incredibly refreshing. Plus, skipping the microwave preserves the original integrity of the brew.

Add Your Favorite Sweeteners

What if the oxidized coffee has become acerbic?  My advice is to stir in your favorite sweeteners. These additions can be anything from sugar to creamers to coffee syrups

Day-old coffee invariably develops a bitter flavor. The sweetness of these mix-ins can help mask the unpleasantness.

old brewed coffee

Wrapping Up: Is It OK To Drink Day Old Coffee?

Yes, it is OK to drink day-old coffee. Whether you want to is a different story. Day-old coffee has oxidized, resulting in degraded flavor compounds.

If you do decide to drink day-old java, drink it over ice. Reheating day-old coffee reorganizes the chemical structure and ruins the taste. Mix in sweeteners, milk, or creamers to help mask the bitterness. 

Alternatively, head to the coffee maker. Brewing a fresh pot might be the best option for you.

Frequently Asked Questions

Can You Drink Coffee Left Out Overnight? 

Coffee left out overnight is safe to drink, so long as you haven’t added anything to the liquid. Any bacteria that grow in the coffee hasn’t had enough time to reach harmful levels. 

Remember, oxidation changes flavor compounds. So drinking old coffee isn’t always the most pleasant experience.