Coffee Aware is reader-supported. When you buy through links on our site, we may earn an affiliate commision. Learn more

Is Drinking Day Old Coffee Bad for You?

Is drinking day-old coffee not good is a question that must have crossed your mind. For a coffee lover, it’s never too easy to leave a coffee behind, but sometimes you get so busy that there is no other option. Not knowing that is drinking a day-old coffee is bad for you? can give a sour taste to your mouth. So, it is always better to drink fresh and flavorful coffee.

Is Drinking Day Old Coffee Bad for You

A day-old coffee, if refrigerated, is safe to drink. But still, it will not taste flavorful. Also, adding milk to it will still give you a better taste. 

To satisfy you, here are some of the questions and their answers that will clear your mind regarding is drinking a day-old coffee bad for you.

Why is fresh coffee the best always?

Freshly brewed coffee always tastes better than day-old coffee. The taste and flavor of a coffee tend to degrade with time which is why it is always better to have a fresh flavorful coffee.

Having a day-old coffee always tastes too acidic. This is because when you heat the mixture of the coffee it gets burned.

How long does coffee stay fresh?

Using a container for storing your coffee grounds and coffee beans can preserve their flavor for a long time. Also, keeping them at a dry and room temperature contributes to it. If you are using a container to store coffee grounds, then they can stay fresh for up to 9 months. An airtight container adds more to the freshness and can make coffee grounds last longer.

Does Refrigerating a coffee keep it fresh?

A refrigerator is still not a good place to keep your coffee. Coffee is like a deodorizer. It is capable of absorbing all the aromas. So, if you keep your coffee in a refrigerator, it will have the aroma of some other things too. 

A refrigerator will keep your coffee safe from molds and bacteria but it fails in keeping it fresh. So, keeping coffee in the refrigerator is not a good idea.

How long can brewed coffee sit out?

Brewed coffee can only sit out for 30 minutes at room temperature. In these 30 minutes, its flavor is not compromised nor does it turn bitter. If the coffee is left for more than 30 minutes, it starts losing its aromatic compounds, turning it into a bitter and less flavorful coffee.

Is drinking reheated coffee not good for your health?

Drinking a reheated coffee is not bad for your health. Coffee is a one-time drink. So, reheating coffee ruins its flavors and brings more bitterness to it. Moreover, reheating the coffee loses its rich flavor and does not taste the same.

Does Coffee go bad overnight?

Leaving a coffee out overnight makes it stale. This happens because of the chemical reactions that happen between the compounds. 

Coffee is rich in volatile aromatic compounds. These volatile compounds are capable of going away quickly. So, if you leave your coffee out overnight it will make it go bad and bitter. 

How do different coffee forms last differently from each other?

Whole beans, ground coffee, and instant coffee all last a different time. Depending on the forms, you can always have a delicious cup of coffee for yourself before it goes bad. 


Coffee when it is in its bean form lasts longer than the other two forms. Right after roasting the whole beans, they give the best taste and flavor. Keep the beans fresh, you can keep them in a container or in a bag to keep them fresh for a long time

If you grind the beans and then store them, they can last for up to a month!

Grounded Coffee

It is better to grind coffee by yourself than to buy a bag of grounded coffee from the market. But still, if you have a bag of grounded coffee from the market then it can stay fresh for up to 2 weeks!

Instant and Quick Coffee

Instant coffee has great taste and flavor. Also, they are the best when they have the proper amount of sugar and creamer in them. For instant coffee, once you open your jar you should use it within 2 weeks. If not, it can get bacteria and mold in it. Also, the particles can get agglomerated.

How long does coffee stay fresh without milk?

Plain black coffee, if kept at room temperature, can stay free for up to 24 hours. However, it would have lost its taste, but still, it will be safe to consume. If it is kept outside for more than 24 hours, it will not be suitable for health.

What happens when you leave your coffee out for a day?

If you leave your coffee out, mold and bacteria start to grow in it. It happens if you leave your brewed coffee at room temperature for up to 4 days. A cup of coffee that is a day old attracts and grows pathogens in it that are extremely harmful to health.

A brewed coffee with milk in it gets an unpleasant taste and odor if you leave it out for a day. It is highly recommended to put the brewed coffee with milk in the fridge. If not, it gives coffee a rancid taste. Drinking rancid coffee will make you sick and is also not safe.


I hope by now you have all the major and minor details about the coffee. Drinking a day-old coffee is not good for your health. It can make you sick. Also, it will change the whole taste of your mouth.  With the above-mentioned time for the different coffee forms, you will now have a crystal-clear idea about how much they last. So, to all the coffee lovers out there! If you want to stay healthy, then do not leave your coffee out for a day!