Find Out the Real Answer to How Long Coffee Keeps!

You may be able to get through the day without coffee, but I certainly can't. While my morning cup of joe gets me going, I usually need an extra boost of caffeine to get me through the afternoon.

My preferred method of making coffee is with a French press, and I'll admit that there have been days when I've re-heated the leftover coffee from the morning. Even though I should probably make a new pot of coffee or use my trusty AeroPress, I don't see any problem with drinking coffee that is several hours old. How long will my coffee be okay if I leave it out?

Coffee is best consumed within 30 minutes of brewing. Black coffee has a very long shelf life before it becomes unsafe to drink, but once you add milk, sugar, or other ingredients, the situation becomes more complicated.

Let's get into the nitty-gritty of coffee safety and freshness so you can enjoy each cup to the fullest and know you aren't putting yourself in harm's way.

Is There a Time Limit on How Long Coffee Can Be Left Out?

When determining how long coffee can sit out, you should consider the method of preparation. After 24 hours, black coffee is still fine to drink, but coffee with dairy in it should be thrown away.

To better understand the perishability and shelf-life constraints, let's...

The Optimal Experience Begins With A New Experience

Experts agree that coffee is best consumed within 30 minutes of brewing for optimal flavor. After 30 minutes, flavors and aromas begin to fade, and after 4 hours, a bitter aftertaste becomes more noticeable. Oxidation, or the reaction of the aromatic compounds in your coffee with oxygen, is the primary cause of this deterioration in flavor.

Your coffee goes through a series of chemical reactions beginning with the brewing process, releasing oils and aromas. These highly evaporable solubles are what give your coffee its distinctive and nuanced flavor, but they quickly degrade and evaporate in the presence of oxygen. The longer your coffee sits out, the more bitter it will taste because the pH rises as oxygen combines with the hydrogen in your coffee in a chemical reaction.

Reheating your coffee causes it to lose even more of its flavor and aroma because higher temperatures speed up the oxidation process. Use an insulated travel mug or thermos to keep your coffee hot instead of reheating old coffee. Zojirushi Stainless Steel Mug and Yeti Rambler are two of our favorites; if you don't like drinking from a travel tumbler, you can always use it to store your beverage of choice and then pour it into your regular mug when you're ready to enjoy it.

Keep leftover coffee fresh by refrigerating it in an airtight container. The oxidation process can be slowed down or stopped in this way, making it a good option for preserving the aromatic compounds. The next day, I don't bother reheating this coffee; instead, I add some milk and sugar and shake it all up to make iced coffee. I admit it's a little dishonest because the extras cover up the coffee's less-than-desirable qualities, but it's still a tasty way to conserve the beverage.

Just to review, freshly brewed coffee is at its peak flavor within the first 30 minutes, and an airtight container is required to store any leftovers. When, exactly, does our coffee stop being drinkable?

For how long after brewing can coffee be safely consumed?

Dark Roast Coffee

The good news for black coffee drinkers is that it can be safely left out for several days before going bad. Taste-wise, it won't be great, but it won't hurt you either.

In its unadulterated form, coffee is not a particularly fertile medium for bacteria to grow because it contains neither proteins nor carbohydrates. It will take at least 4-7 days, and probably longer, for mold to start growing. Even black coffee should not be left out at room temperature for more than 24 hours.

Always keep leftover coffee in the refrigerator in an airtight container.

Cafe au lait

Things get more precarious if you like your coffee with milk, or if you like your latte or cappuccino frothy. Coffee with milk or a dairy substitute should be consumed within two to four hours of brewing. At this point, you can throw it away. Temperatures between 32 and 86 degrees Celsius (90 and 30 degrees Fahrenheit) are ideal for storing milk and other perishables. Bacteria can multiply rapidly in temperatures between 40 and 140 degrees Fahrenheit (4 to 60 degrees Celsius), rendering the coffee unsafe for consumption after just two hours.

The coffee's flavor and aroma will quickly fade after 30 minutes, just as they do with black coffee. You might not notice the loss of flavor as much if you usually drink milk-based coffee beverages, especially those with sweetener, but a lukewarm latte is still not very appealing. If your coffee has taken on a sour flavor, it's time to toss it.

You should use an insulated thermos or tumbler if you take your time drinking so that your beverage doesn't get unsafely cold.

Do not refrigerate stale coffee containing dairy, and never reheat a milk-based beverage. Even though reheating has a small chance of killing bacteria, the drink will taste terrible and is not worth the risk.

The Benefits of Cold Brew Coffee

The shelf life of cold brew coffee is longest. Since heat hastens oxidation, storing it in the fridge for up to two weeks keeps it tasting fresh.

Making a cold brew concentrate and then diluting it with water and flavorings per serving is the most effective method.

Cold brew is delicious, as it retains more of the coffee's natural flavors and aromas than any other preparation method. Cold brew is great year-round, but it's especially useful on hectic mornings. An additional few minutes are needed to prepare cold brew, but once it's done, you can just grab it out of the fridge and go.

Green Coffee Bean Extract

But unlike flavor and aroma, caffeine is quite stable and won't degrade in your brewed coffee. However, the antioxidants in freshly brewed coffee eventually degrade, so reheated coffee isn't as healthy as a new cup. That coffee from yesterday could have been thrown away for good.

You should always make sure your coffee maker is spotless. While coffee beans don't tend to attract bacteria, your coffee maker might, and one particularly nasty strain, Pseudomonas putida, can break down caffeine.

Check your user manual and give your coffee maker and coffee pot a thorough cleaning every so often to make sure you're brewing the best-tasting coffee possible using your preferred brew method.

Summary

• Within the first 30 minutes of waking up, you should have your morning coffee.
• About four hours after brewing, black coffee will still taste good, but it can be safely consumed up to seven days later if stored in an airtight container in the refrigerator.
• Cold brew is an excellent way to drink new coffee with almost no waste.
• Two hours is the cutoff for discarding milky coffee.