Can You Leave Coffee in a French Press? Here’s Why It’s a Bad Idea

Can you leave coffee in a French press? Is it going to spoil its taste? 

Stick around, in this article, I’m talking about brewing with a French press and what really happens when you leave coffee in it for hours. I also share some of the best practices for making coffee with a French press.

Let’s dive in. 

Can you leave coffee in a French press? 

It’s not one of the best practices for brewing with a French press. One of the main reasons is coffee extraction continues causing over extraction which makes your coffee taste bitter. Plus, mould can grow on the inside and it will be more difficult to clean it up. 

Why you shouldn’t leave coffee in your French press

What many coffee lovers do is fill up their French press with water and make excessive coffee (a French press can brew up to 4 cups of coffee in 1 go) and save it for later. But by the time they have the remaining of this coffee, its taste has changed.

Let’s talk about the 5 main reasons why it’s not a good idea to leave coffee in your French press. 

1. Over extraction

One of the main reasons is that coffee keeps interacting with water and as a result, it leads to over extraction turning your coffee bitter. Coffee acids, oils, and lipids are transferred from the grinds to water, making your coffee richer than it should be meaning that this ongoing process spoils its taste. Simply put, as long as water interacts with coffee grounds there’s going to be ongoing extraction. 

Now, it’s no good to extract too many coffee flavours and aromas as the taste of your coffee becomes unpleasant. Oxygen, moisture, and heat turn coffee beans/grounds stale 

2. Coffee gets stale

This happens when you open a pack of coffee beans/grinds. Once you open the pack coffee starts getting stale.

What about brewed coffee? 

Brewed coffee is the one that gets stale the fastest, that’s why it’s recommended to have your coffee as soon as possible (ideally less than 25 minutes). So, what happens with the coffee that stays in your French press? You guessed it, it gets oxydated and becomes stale. It’s wise to brew smaller amounts of coffee each time to make sure you have it fresh.

3. Reheating your coffee spoils its taste 

It takes about 10 minutes for hot coffee made with a French press to hit room temperature, meaning that if you have this coffee later than minutes you’ll need to reheat it. The trouble with reheating coffee is that it’s not going to taste as good as fresh coffee. You can reheat it on a stove or in a microwave but either way, this process is going to spoil its taste. One way to go around it is to add milk or creamer to make it taste better. 

4. Mould grows on the inside of your French press 

Did you know that it takes 24-48 hours for mould to develop? This is bad news for your coffee that stays in the French press as it’s going to spoil your coffee’s taste. And if you don’t wash your coffee gadget properly, the odds are your next brews are going to taste weird. It’s also worth mentioning that mould develops faster in hot temperatures. If you live in a country with a hot climate, mould is going to grow faster, so it’s key not to keep coffee in your French press. 

5. Coffee oils and lipids are built up on the inside

The longer you keep coffee in your French press the more coffee oils and lipids are built up on the inside, leaving marks and making it harder to clean it. To avoid the hassle of scrubbing the inside for a long time, it’s wise to not keep coffee in your French press. 

Where to put your coffee instead? 

As already mentioned keeping coffee in your French press isn’t the best idea. Let’s discuss 3 alternatives.

1. Put it in the fridge 

There’s no harm in putting your coffee in the fridge as long as it’s only for 3-4 days, otherwise, it’s not going to taste great. All you need to do is pour it into an empty container and put its lit on. It’s not going to taste as good as fresh coffee but you can add sugar, milk, or creamer to add an extra layer of taste to it. 

2. Put it in a thermo

Because they’re made of stainless steel they keep the temperature high for hours, so if you brewed coffee in the morning, you’ll still be able to drink delicious hot coffee in the middle of the day.

3. Brew excessive amounts when needed

Brew an excessive amount when you invite friends and family around and treat them to a delicious cup of coffee. But if you’re on your own, there’s no harm in brewing enough coffee for just 1 cup. 

Tips on how to brew delicious coffee with a French press

Here’s a number of tips and tricks on how to brew better coffee with a French press:

• Use fresh coffee to brew delicious coffee
• Go for coarse coffee grounds to avoid over extraction and at the same time brew rich coffee
• Let the coffee bloom, so the right amount of flavours and aromas are extracted 
• Use filtered or bottled water as tap water might spoil your coffee’s taste 
• Grind your own beans instead of buying pre-ground coffee

Let’s wrap it up

Since you made it to the end of the article, I believe you’ll be able to answer the question of ‘Can you leave coffee in a French press?’ Leaving coffee in, isn’t one of the best practices and it’s wise to avoid doing it. Stay tuned, more articles about French press are going to be published soon. 

FAQ

Let’s go through a couple of FAQs to help you get a better understanding of the topic. 

How long can I leave my coffee in French press?

You can leave it for about 4 minutes to bloom, this is the process that coffee is brewed and coffee flavours and aromas come out of the coffee grounds and mix up with the hot water. 

You can experiment with leaving your coffee a bit longer (like 30 seconds) to make your coffee richer, but if you’re not into rich coffee, I suggest you stick to the 4-minute rule of thumb and you’ll be just fine. 

Can you leave coffee in the French press when making Cold Brew? 

Yes you can, the whole process lasts up to 12 hours, so obviously you should leave the coffee to steep so its flavours and aromas to be extracted. But once your Cold Brew is ready, it’s a good idea of putting it in a different container or even popping it in the fridge to keep it cool. 

Is it OK to leave coffee overnight?

The short answer is: it depends

As mentioned, you can pop it in the fridge or in a thermo to be on the safe side. However, it’s not wise to leave it in the French press overnight as mould might start to develop and spoil your coffee’s taste.