6 Reasons Your Coffee Is Bitter And How To Fix Them

3 min read 3 Comments

6 Reasons Your Coffee Is Bitter And How To Fix Them

It’s a familiar story. Wake up in the morning, head to the kitchen, dump some ground coffee into the coffee machine, have a guess at how to brew it, taste it and it’s so close to undrinkable it might as well be. 

Poor brewing skills prevents us from fully enjoying this wondrous drink. 

However, there are solutions for these problems. 


1- Over Extracting

On the list of reasons why your coffee might be tasting bitter — Over extracting is definitely on the top of that list, and is arguably most common mistake.

Simply, over extracting is where you pull out too much of the coffee flavour from the ground beans. 

The main flavors associated with over extraction are- bitter, dry, astringent, hollow and empty.

There wouldn’t be a coffee drinker alive that hasn’t tasted over extracted coffee.

How do we fix this? 

Slightly coarsen the grind to speed up the extraction time. Or just stop the brewing time earlier.

2- Water Too Hot

Perhaps an overlooked issue, especially when brewing espresso coffee on your home machine. 

Brewing water that is too hot can result in bitter and astringent coffee and water that is too cold can result in sour and/or overly bright coffee.

Perfect espresso machine brewing temperature should be around 94c +/- a few degrees. 

For manual brewing with a standard kettle, just boil the water and let it sit for 40sec to let some of the heat dissipate.


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3- Coffee Bean Quality 

Unfortunately, not all coffee is created equal. Coffee bean quality has the most significant impact on cup quality. 

Coffee, like wine, is graded on a scale of 0-100 with specialty coffee grade starting at 80. 

Coffee that is below the 80-point mark is broadly referred to as ‘commodity grade’ and is commonly used by the large coffee roasting chains or is what you would find in the Supermarket.

Generally speaking, commodity grade coffee has more undesirable flavour notes such as grassy or vegital, dirty, dull or muted. To combat these handicaps coffee roasters will often heavily dark roast the coffee beans, effectively roasting out the poor flavours. This leaves the customer with coffee that has notes of leather and wood, and the beans are a very dark shade of brown, bordering on black.

These coffee beans, no matter how well you brew them will always have bitter and astringent notes. 

Fox Coffee always uses Specialty Grade Beans usually with a minimum point score of 82.


4- Roast Type

Your choice of coffee bean may have been roasted too dark.

Every roast type has a specific way it is intended to be brewed. 

Light Roasts are roasted to be brewed in manual pour-over setups and coffees used are usually brighter and more acidic.

Traditionally Dark roasts are intended to be brewed on home espresso machines, plungers or stovetops and they gain some sweetness and balance when the coffee is cut with milk.

Bitterness is inescapable when you use the wrong coffee in the wrong brew method.

5- Too Much Coffee

Many of us like to add a lot of coffee to our brews because that makes the taste stronger; however, if you go overboard, you will have a bitter taste because the level of water (or the coffee to water ratio) is out of step with the amount of coffee. 

It’s better to fully extract the coffee first, then to add more coffee to the next brew to hone in on a perfect strength.



6- The Grind

You need to take care not to grind the beans too finely. If you do so, you risk over-extracting the coffee while you do that; as a result, the end taste of the drink will also be bitter.

Every brew method has a precise grind type that you need to stick to; these have been tried and tested over many hours of trial and error.



As you can see, coffee can be bitter for a variety of different reasons. Luckily, once you become more intricately familiar with the brewing process; you can eliminate most of these hurdles on your way to an excellent cup of coffee!


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3 Responses

Natalie George
Natalie George

September 13, 2023

Thanks for these tips I have been overgrinding my coffee and will be doing it less in future. Big difference.


September 14, 2021

Just what I have been wrestling with! Great tips and some good actionable guidance. The grind tip really made a difference for me.

Peter Forrest
Peter Forrest

March 17, 2021

Changed to a Aero Press good coffee every time.

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