Can You Drink A Day Old Black Coffee?

We all can admit to drinking coffee that has been sitting out for hours. While this can be a coffee lover’s worst nightmare, it has happened to all of us at least once in our lifetime. People who work in a corporate setting are more prone to such scenarios than people who work in remote settings. 

But regardless of what we do, is it safe to sip a day-old black coffee? This blog post will surely answer all your queries regarding this issue; make sure to give it a complete read!

Drinking A Day-Old Black Coffee:

A short answer to your question is “YES” you can drink your day-old black coffee. However, the taste of that black coffee will be extremely bad and will not live upto your expectations. This is because black coffee can hold up to its taste for almost 4 to 5 hours. After that, your black coffee will lose its flavor and start tasting bad. 

Your black coffee has the capacity to stay just fine almost for a week, only if you keep it in a refrigerator. If you leave your black coffee at room temperature, and that too for days, this will start the molding process, and your coffee will no longer be drinkable. 

If you’ve added any dairy products, including non-dairy milk, then it would help if you skipped drinking that coffee, as this type of coffee can only stay fine for a couple of hours.

Moreover, if you have the time and ingredients to make a new coffee, you should always prioritize that instead of keeping your hopes high for a leftover coffee. 

LifeCycle Of A LeftOver Coffee:

Most people need to be aware of what their coffees go through once they have left without drinking it. We know that everyone has their definition of “not too good” and “bad.” However, to generally explain to you the lifecycle of your leftover coffee, we have included this section.

When it comes to coffee, it is usually the flavor most affected by such a delay in your drinking. Coffee starts to lose its flavor quickly after 30 minutes of brewing due to the ingredients being in the open air.

On the other side, some people have the habit of brewing an entire pot for the whole day without noticing any particular difference in taste.

Well, from a general point of view, some factors affect the lifespan of leftover coffee; some of these factors are listed below for you to get to know them better and prevent your coffee from losing its taste. 

Factors Affecting Your Leftover Coffee:

Here are some of the factors that contribute to making your leftover coffee taste bad or simply make you want to throw it away, 


One of the first things that will happen to your leftover coffee will be oxidation. The oxidation process will make your coffee lose all its flavor and instantly make it taste bad.

The hotter your coffee, the more likely it is to oxidize, so you better keep that in check. If you want to avoid this situation, you can always buy a thermal mug for yourself, which can always keep your coffee at a pleasant temperature. 

Thermal mugs are a great asset if you are a coffee lover and often tend to leave your coffee for longer durations because of your hectic work or other issues. These mugs are a great asset to any coffee lover, especially if they enjoy a hot coffee on the go. For black coffee, try to store your coffee in a tight container and in a refrigerator.

Rancid Oils:

The second thing that will affect your leftover coffee is rancid oils which can easily act on your coffee for a duration of 4 to 5 hours. Rancidity is the next level of the oxidation process; this means that after the molecules of coffee get oxidized, the second thing that will be in contact with oxygen will be the oils in your coffee. 

This single reaction has a lot to do with your coffee’s taste. This process further starts the rancidification of free radicals that can form in that leftover coffee and diversely affect human health. Again airtight containers and thermal mugs can easily slow down this process and save your stomach from experiencing such a horror.


As we have mentioned earlier, that black coffee can stay fine in a refrigerator, but if you leave it at room temperature, you will start noticing a layered mold will grow.

When discussing whether you can drink day-old coffee, it’s safe to say that you can without the risk of high bacteria levels. However, the process of molding is slow and will likely take time. It is best to avoid such day-old coffees so that you don’t end up contracting any bacteria and causing some serious concerns to your body. 

To avoid moulding, you should also clean your coffee makers every 3 to 4 days to clear any possible contamination or bacteria. 

The quality of the beans you use to make black coffee also greatly impacts its quality and taste. So it is better to choose high-quality beans rather than cheaper ones and store them in a dry and cool place within an air-tight container. 

Apart from taste, the caffeine in your coffee will remain active even if it is a day old, but it might negatively affect your system rather than give you any energy. 

Concluding Thoughts:

We hope by now you must have understood how you can drink your day-old black coffee and what things you should consider before drinking your leftover coffee. By following the above mentioned steps, you can always eliminate any possibility of hurting your stomach or having any health issues by drinking leftover black coffee. 

Apart from this, you should also consult medical experts and consider their advice so that you don’t end up causing any concerns for your health. 


I'm Aleena but most people know me as DeesCoffee. I completed my bachelor's degree in Fashion & Textile from Gift University. Personally, I'm a coffee lover who likes to have at least two times a day. Now I've DeesCoffee, here I explore different questions about brewing a perfect cup.