How Long Can Leftover Coffee Sit Out Before Going Bad?

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It happens all the time: you brew a perfect cup of coffee, splash in a little milk, then… get distracted as you get ready for the day. Or you become focused on work tasks and before you know it, your coffee has long gone cold.

So how safe is leftover coffee to drink? Read on to know how long you can leave your coffee out before it goes bad.

How Long Is Black Coffee Safe to Drink?

The good news is, if you brew coffee at home or help yourself to the pot at work, black coffee is the safest type to drink if it has been sitting out. Even if it is hours old, it isn’t dangerous to consume. You might just have to sacrifice taste.

It’s still a good idea to keep track of how much time has passed since it was brewed. A pot of coffee has two milestones:

  1. After thirty minutes, it begins to lose flavor.
  2. After 4 hours, it will become more acidic as the oils within the coffee begin to go bad.

There is nothing wrong with making yourself a big pot and helping yourself to it throughout the morning. If coffee was brewed at lunch, you can feel good about pouring yourself a cup for a 2pm or 3pm afternoon pickup.

How Long Is Coffee With Milk Safe to Drink?

Milk is not safe to consume if it’s been unrefrigerated for two hours or more. If you’ve added milk to your coffee, make sure you drink it within this two-hour window to prevent the milk from spoiling.

It’s not just traditional milk. This rule of thumb applies to anything perishable that you have added to your coffee, including:

  • Flavored creamer
  • Half and half
  • Dairy milk alternatives such as oat milk or almond milk


The bottom line: if you pulled something out of the fridge and added it to your coffee, you will need to drink it within a couple of hours.

Will Microwaving the Coffee Kill the Bacteria?

Microwaving is an effective method to kill bacteria on your food. According to the CDC, the microwave you have at home can indeed kill bacteria and viruses in as quickly as a minute.

The problem, however, is that microwaves don’t distribute heat evenly. Often, there will still be pockets of cold in the middle of your drink or food. Microwaves with a higher power are also able to disinfect more thoroughly, and power varies widely depending on the product.

You can microwave your coffee to heat your drink back up to an ideal temperature–but don’t count on it to make your beverage safe to drink if you have added milk or creamer.

One last thing: if flavor and acidity are important factors to your perfect cup of coffee, your best bet is to drink up as soon as possible.

In general, leftover coffee can sit out for up to four hours before the oils within coffee begin to go bad. If milk was added, it can sit out for up to two hours. Keep this timeline in mind, and you can ensure that your coffee is perfectly safe for consumption.

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