Avoiding sour or bitter coffee

If your coffee has a very sour or bitter taste it could be down to the following factors. So if you are struggling to work out why your coffee tastes bitter or sour, read on and take note.

However if you prefer lemons, vinegar, bitter greens and sour sweets then you can use this information to make your coffee even more bitter or sour!

Coffee is very much a matter of personal preference and taste. Some people appreciate a hint of bitterness in their coffee whereas others prefer a nice smooth taste.

Our aim here is to help you to adjust your coffee making method to produce the taste you prefer.

Why does my coffee taste bitter?

Over extracting the coffee pulls out more caffeine and this has a very bitter taste.

To shorten the extraction time on a coffee maker increase the pressure if this is an option and cut the shot pulling time.

This can vary according to bean type and grind coarseness so there is a big element of fine tuning required.

If you are using a French press then you are probably taking too long to steep the coffee.

On a pour over coffee maker you should open up the pour rate if this is an option to allow faster extraction, alternatively use less water and top it up with hot tap water.

Tune your coffee machine

How do you tune your coffee maker so you can avoid bitter coffee?

  1. Time a full (long) shot from your machine, it will typically be around 30-40 seconds or so.
  2. Take 4 cups, as you extract the coffee shot replace each cup after a few seconds (10 seconds for a 40 second extraction).
  3. Now take each cup and taste it and you’ll learn what is going on through the extraction process.
  4. You’ll notice the first is very strong coffee, with all the notes of the coffee taste, whereas the final one will taste quite bitter.
  5. Now depending on how you prefer the middle two shots you’ll have found your extraction time.

We have a full guide to tuning your coffee maker.

For most machines you want to cut this down to the minimum.

Don’t worry about only having a dribble of coffee, because you’ll add hot water and/or milk to it and will have the greatest tasting coffee you’ve ever made.

Most machines will allow you to adjust the extraction time, with some having a long and short extraction button and others allowing you to set a more precise time.

Bitter coffee from Pod coffee machines.

Pod coffee makers such as the Tassimo, Nespresso, Dolce Gusto and Illy are popular but most people with these try to fill the cup with coffee.

Instead aim to extract a very short shot of coffee, espresso style (just one or two fluid ounces typically done in around 20-25 seconds).

Then top up with hot water and milk according to taste. Most allow you to stop the extraction by pressing the button again or by setting an extraction time.

Do not try to fill the cup with coffee from a single shot of coffee grinds, or you’ll get a very bitter coffee.


Temperature of water used can cause bitterness in coffee. If the water is too hot it will pull out the bitter notes and scorch the grinds. Aim for 90-95 C° or around 200 °F

Some cheaper stove top coffee makers and some cheaper home espresso machines rely on steam over pressure to extract the coffee, and this is generally far too hot.

Sour coffee taste

A coarse grind will usually cause the coffee to be under extracted and this can add a very sour note to the coffee.

A sour taste can also be down to the bean chosen and light roasts tend to be on the sour side.

Just like a fine wine though you can build an appreciation for the bitter and sour notes in coffee and refine your tastebuds.

Grind and its effect on sourness and bitterness.

If the grind is too fine you can over extract the coffee.

A finer grind allows more compounds to flow from the bean to the extracted shot, and sometimes this is not a good thing unless you are making Turkish coffee, in which case you want it to be powder fine and end up with a really bitter coffee.

The ideal grind coarseness depends on

Robusta coffee beans tend to add a bitter note to coffee so you might want to revise your blend and go with a higher Arabica content coffee or 100% Arabica.

So the reasons for bitter coffee are

  • Over extraction
    This is the no 1 reason for a bitter coffee, especially on cheaper budget machines, and peoples tendency to want to fill an entire cup.
  • Too fine a grind
    A poor qualiy grinder will give varying sizes, and the smallest fragments will be pulled into the coffee shot and make it taste bitter
  • Water is too hot
    Ideally the water should be around 90-95 degress celcius, hotter than this and you overheat the beans and end up with a bitter mess.
  • Very dark roasts
    Typically the darker the roast the more bitter it will be. Some coffee shops have almost created a trademark for bitter smokey strong tasting coffee. The bitterness from dark roasts is actually quite pleasant and more subtle than from other issues.
  • Choice of bean
    With Robusta typically being more bitter than Arabica, but just as the way grapes are grown will affect the taste of a wine, so too the taste of the coffee is affected by the way the coffee beans are grown, stored and roasted.

So hopefully you are fully armed to avoid the problem of bitter coffee.

Use the Coffee Revolution tuning method to set your machine up and you’ll never pull a bitter espresso shot ever again.

Now you are familiar with this part of your machine, it’s time to explore the many options of coffee shots and coffee roasts.