Sometimes you forget you've made a cup of coffee, for several hours maybe. Or, maybe you're stranded in the middle of nowhere and your coffee is 2 days old.
How long does brewed coffee last ? And how does it break down, so you know what's going on with it ?
We'll talk about this, and anything else that will help you in this respect. But first, let's see just how long a cup of fresh coffee will last.
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So how long does brewed coffee last ?
In terms of flavor, your coffee is only good for the first hour after it's been brewed.
If we're looking at health hazards, any coffee left out past 12 hours becomes a breeding ground for bacteria. This is especially true if your cup of coffee is uncovered, on the counter.
There are exceptions for cold brewed coffee, and there are ways to prolong the shelf life of hot brewed coffee.
I'm going to guide you through all of that, and give you a tip on how to make sure your coffee doesn't have to stay forgotten in the first place.
But first, let's see what happens to coffee that you've left out in the open.
Read Also: Does Brewed Tea Go Bad ?
What ruins brewed coffee in the first place
First off, coffee loses its flavor after the first hour. You'll notice the fragrance of coffee oils will become dim, and the general aroma of coffee will fade away after the first hour.
This is because all flavor in coffee is transferable, and will evaporate. This means that coffee beans left out in the open will lose their aroma too, as will tea leaves and the infusion made from them.
So, your nice cup of coffee will be just a muddy brew, still containing caffeine, but with barely any taste at all.
This all happens in the first hour because the coffee, while it cools off, helps the aroma evaporate quite fast. The fact that it's hot makes the evaporation process even faster.
Reheating your coffee in the microwave will only ruin the flavor further. You're better off just making a fresh cup.
Looking at the impact on your health, coffee that's been left out for more than 12 hours should not be consumed.
Within 12 hours the coffee's had enough time to:
- reach room temperature and remain there
- collect specks of dust and tiny bacteria that are present in the air
- provide moisture for bacterial/fungal growth
All in all, not a pleasant thing to think about. This is especially true if your coffee has been left without a lid. even worse if your lips have already touched the coffee.
This is because the bacteria that's naturally present in your mouth and on your body will multiply in an un-friendly way in your cup of coffee.
It's the same reason you're not meant to stir a pot of food with a spoon you've already put in your mouth.
Back to coffee, keep the 12 hour limit and you'll be fine.
However the coffee oils in your coffee will go a bit rancid in that time anyway, even if no bacteria breeds there.
Again, you're better off making a fresh cup of coffee.
Keeping your coffee in the fridge makes it last longer
Now what if you made a big batch of coffee, and had a large amount left over ? You could argue that throwing it away will be a waste, and it would be, in a way.
If you were to transfer it to a clean container and put an airtight lid in it, and then put that in the fridge, your coffee could potentially last up to 3 days.
Keep in mind that the flavor will still go away, bit by bit. The health risks will be minimized, though.
Bacteria needs a temperature warmer than any fridge can offer, so you're good.
This is only true for coffee that's:
- freshly brewed
- never had dairy or sugar added
- never been stirred with a used spoon or other utensil
- places in a clean, airtight container
If you've already added dairy to the coffee, then I can't vouch for the 3 day period. Dairy spoils fairly quick after being exposed to air, so I would venture that coffee with milk, left in the fridge, should not be consumed after 24 hours.
Even if your coffee somehow remains safe and clean, the aroma will change.
Any liquid that's been brewed with hot water will taste very different when in a cold state.
This is true for tea, soup, sauces, icings, anything. Sometimes you want this change, like with pudding for example.
With coffee and tea, this is not a good idea. It'll taste very flat.
The best way to reuse hot coffee that's been kept in the fridge is to pour it in ice trays, and store those in the freezer. Then, you can use the coffee cubes in some amazing iced coffee or lattes.
Cold brewed coffee will last longer
If you were to brew your coffee cold in the first place then this whole thing would be avoided.
Cold brewed coffee has a much longer shelf life than hot brewed coffee, simply because the chemistry is different.
And also because the aroma and coffee oils are extracted at a very low temperature, it take longer to brew but the flavor lasts so much longer.
In fact, it can last up to 2 weeks in the fridge, in an airtight container, unsweetened.
So, you'd be having 'fresh' coffee for longer.
You can't microwave this coffee though. You're ruining the flavors because:
- cold brewed coffee tastes different (bad) when heated
- heating already brewed coffee evaporates a lot of the aroma
So you're pretty much mucking things up by reheating any coffee, at all.
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Adding dairy shortens the safe time for coffee
Whenever you add dairy to your coffee, you;re doing a few things. You're:
- slowing down the caffeine - it still works, but slower
- helping the coffee go bad faster
- giving the coffee a smoother, creamier taste
Now, since most of us drink our coffee on the spot, we don't really notice the coffee going bad as we drink it. The process doesn't happen that fast anyway.
But, it's still happening and if you were to leave your cup of, say latte (mostly milk) out on the counter for 24 full hours it would be pretty bad.
The milk will be no good after the first few hours, since room-temp milk spoils easily.
The whole drink will become a breeding ground for bacteria and fungi, even if you don't see it sprouting legs just yet.
And the aroma will be gone.
But this will all happen sooner than with a cup of black coffee, since dairy happens to break down very fast.
So if you want to prolong your coffee's shelf life, don't add creamer just yet.
If you've already added creamer, took a few sips, and suddenly have to leave the house for 10 hours, don't drink that coffee when you come back.
Best to get yourself a good thermos/travel mug
What should you do then ? Aside from not leaving coffee out in the open.
Well, you can always brew in smaller batches, and only drink one cup of coffee at a time. That way you're sure each cup will be fresh.
You've probably thought of that already, but a reminder is nice from time to time.
But what about people who need their large amount of coffee to be available at all times, already brewed, ready to be enjoyed at a moment's notice ?
Then all you're left with is a travel mug or thermos. As long as it's airtight, and keeps the contents conveniently hot (or cold), then it's going to work just fine.
If you've got such a thing at home, then you're all set. Make sure it's clean and the gasket is very well scrubbed, and you're ready to use it.
If you don't have a thermos/travel mug, then you can check out this one, and see how you like it.
I'm showing you here the largest size they have, which is 30 oz/ 890 ml. There are 2 smaller sizes as well, and you can pick out from several colors they have available.
It's a big travel mug, double walled, insulated, and the lid is splash proof.
I doubt there's much you could do to this thing to break it or have it leak.
It comes apart fairly easy, and is easy enough to clean.
You can check the listing on Amazon here, and read the reviews as well.
When using an insulated travel mug, or a thermos, remember that even in this case, the coffee won't be good more than 24 hours. Even if was airtight, even if you never stirred it with a used spoon, and never added dairy.
There's a point at which the thermos can't help you anymore. And the whole coffee will become stale as well. The more often you open it to pour a bit, the faster that happens.
Final thoughts
I hope you found your answer here, and know how long to let your cup of fresh coffee stand.
Often it doesn't even see more than a few minutes, but when it's forgotten, it can even make it to the next morning.
Ah well, such is life. Best to make sure your coffee is always fresh, or at least kept in a container that can keep it fresh.
If you want to know more about coffee or tea, feel free to check the related articles below. Who knows what else you might find ?
