How Long Can You Leave Coffee Sitting Out?

crazy by Editorial Staff | Posted on November 25th, 2022

Coffee is a wonderful beverage to sip in the morning or at any other time of the day. Many people like it because of its robust flavor and scent. But how long until it spoils if you keep it out in the open?


Of course, how coffee is stored and the additions, such as milk or creamer, affect how long the beverage will last. Several variables, including temperature, air exposure, and storage technique,, influence brew coffee’s shelf life.

cup of coffee with steam on black background

After brewing, plain black coffee may often be left at room temperature for more than 24 hours. Though it may lose some natural flavors, it will still be considered safe to ingest. However, hot coffee with milk or creamer should not be kept out for longer than one to two hours. This also applies to coffee with almond milk.

However, drinking hot coffee with milk added is only safe for a short time at room temperature—about an hour or two. Milk is a perishable food that can spoil. The milk may curdle and go sour if you leave it too long. 

All milk-based beverages, such as lattes, mochas, frappuccinos, and other well-known coffee drinks you purchase from the coffee shop, fall under this category.

What occurs to coffee when it is left out?

Steam rising from a white cup of hot coffee with a spoon on a saucer over a wooden table in the cafe. Close-up of a refreshing hot cup of a coffee at a cafe.

Coffee will surely start to smell terrible if you keep it out too long. The coffee is only good for 30 minutes after brewing, according to individuals who are meticulous about the flavor profile of their caffeinated beverage.

Meanwhile, others would prepare a large pot of drip coffee on Sunday and drink it every day for the remainder of the following week without putting it in the refrigerator. However, what exactly occurs to your coffee if you leave it out for that time? 

Decline of flavor

Oxidation is a chemical process that causes coffee to become bad. Fairly frequently, this reaction involves the transfer of electrons from one molecule to another.

The flavor of coffee is made up of extremely volatile aromatic chemicals that readily oxidize when exposed to air, which is how flavors are lost. At higher temperatures, this process moves forward considerably more quickly. Therefore, cold brew coffee retains its flavor for longer than hot brew.

Most of the delightful flavor and aroma of your newly made coffee has been gone by the time it has cooled off, typically taking around 30 minutes.

​​Degradation of coffee oils

Coffee oils and oxygen combine, which causes rancidity. One of the oxidation processes that cause the unpleasant coffee flavor is rancidification. Free radical production, which may result in oxidative stress and have a detrimental effect on human health, is another effect of this interaction.

Coffee oils are more stable than the aroma above components, which deteriorate quickly. But the oils will turn rancid over time, more quickly if they are exposed to air or light or kept at a higher temperature.

So, you should store your coffee in an airtight container if you wish to reduce the rancidification of the coffee oils. It would take longer if you kept your coffee in the refrigerator.

Milk spoilage

Milk must be kept at or below 40 °F (4.4 °C) to be fine to consume. As a general rule, coffee with milk that has been out for more than two hours at a temperature between 40 °F and 80 °F (4.4 °C and 26.6 °C) should be thrown out.

If the temperature is greater, you should discard the milky beverage after one hour.

The appearance of mold and bacteria

Brewed coffee will ultimately develop mold if kept outside for an extended period. If the coffee is kept at room temperature after brewing, this often occurs 4 to 7 days later.

Pseudomonas, a kind of bacterium renowned for having the capacity to degrade caffeine, was one of the most often discovered bacteria in coffee makers.

How long does caffeine remain in coffee after brewing?

Cup of hot coffee drink on the table

Caffeine is stable and does not evaporate or dissipate after brewing, unlike other volatile taste ingredients. The absence of flavor and scent may be noticeable, but not the caffeine.

Even several hours later, the amount of caffeine in your cup of coffee would not change.

Factors that keep coffee safe to drink

Temperature

The drink’s temperature significantly impacts how safe it is to consume. Brewed coffee will become stale, bitter, and sour if left at room temperature for extended periods.

Coffee is safe to drink whether it is hot or when it is kept cold for later consumption. Just be careful not to overheat the coffee by reheating it too frequently or consuming coffee stored in the refrigerator for more than a day.

Milk content

How long a cup of coffee may be safe depends greatly on whether it contains milk or cream. Adding milk to your coffee would surely reduce its shelf life because dairy tends to spoil rapidly if not kept cool.

It will probably stay a little nicer for a little while longer if you are drinking black coffee without added dairy.

Container

The life of your freshly made coffee will remain longer if you use a container or mug with a cover since the oxidation process will take longer.

However, the reverse occurs when a standard mug without a lid or cover is used. Therefore, you should use a container or cup with a lid if you’re a slow coffee drinker.

Conclusion

We advise enjoying your hot beverage as soon as possible to reduce the bitterness in your drink because leaving it out unprotected and unrefrigerated for longer than 30 minutes will significantly alter the flavor of your coffee.

While drinking black coffee a day after brewing is theoretically okay, milk-flavored coffee drinks should be consumed right after.

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Disclosure: No compensation or free products were received in exchange for writing this review.

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Editorial Staff

The editorial staff at Crazy Coffee Crave is a team of coffee enthusiasts & Baristas who enjoy the one thing we all think about as soon as we get up in the morning. Trusted by thousands of readers worldwide.