It is impossible to completely eliminate the bitterness of coffee since it is a characteristic of coffee. However, the bitter taste should not overshadow the rest of the flavors in the cup. Therefore, when brewing coffee, we should always try to find the perfect balance where the bitterness does not dominate the rest of the flavors.
A well-balanced coffee has a natural sweetness and a light acidity that perfectly complements a subtle bitterness. Bitterness and acidity should be present in the cup but barely noticeable when drinking the coffee.
It is possible to reduce the bitterness of coffee, but it is necessary to identify the origin of this bitterness and correct it. The bitterness should never be eliminated by adding salt, milk, sugar, etc. If anything else is added to the coffee, it is because you want to enjoy the taste of that other additive, but never to correct it.
Influence of the coffee bean on bitterness
The Arabica bean has less bitterness than Robusta, but being a more delicate bean, it is also more expensive due to the lower yield of the coffee plant. Most commercial coffees use Robusta beans, so you can significantly reduce bitterness by changing the bean type.
Aside from the type of bean, the care the plant has received greatly influences the coffee’s final flavor. Therefore, even when acquiring Arabica coffee, make sure the beans are regular in shape, size, and color. The “discarded coffees” produce a particularly bitter taste in the cup.
Try to acquire specialty and single-origin coffees since these coffees usually leave very little bitterness in the cup. The image below shows the difference between a specialty bean and a commercial bean; in the specialty one, all the beans are uniform, while the commercial is the opposite.
Note: Most commercial coffees do not indicate the type of bean used, so you should assume they use a Robusta coffee bean or “discarded” beans.
Influence of roasting on coffee bitterness
You may already be using an Arabica bean but still, feel such bitterness in your cup that it does not allow you to enjoy the rest of the flavors.
The second most important factor to control bitterness, after the choice of coffee bean, is the type of roast. Bitterness and roast are very closely linked; whereas the degree of roast increases, the level of bitterness increases.
For this reason, the bitterness and charcoal or ash flavor will predominate in a dark roasted coffee.
Use light roasted coffee beans
Lightly toasted slices of bread have a characteristic color, flavor, and smell derived from the Maillard reaction. However, smoky, bitter, and ashy flavors appear when that slice is burned.
When roasting coffee beans, the same happens as when toasting bread. Although coffee does not “burn”, it does develop flavors similar to those produced by excessive exposure to heat. You can reduce bitterness by choosing light or medium roasted coffees.
Influence of the preparation of coffee on bitterness
If despite using a good light/medium roast Arabica bean, you still feel your coffees are too bitter, you may be doing something wrong during the brewing process. You are probably over-extracting the coffee since bitterness is a characteristic consequence of over-extraction.
How to avoid over-extraction?
Whatever the method of preparation that you use, the following factors are valid to avoid over-extraction:
- Grind the beans slightly coarser than you are currently doing.
- Lower the water temperature slightly. The ideal temperature is 197ºF, but you may have to lower it slightly to avoid over-extracting your coffee beans.
- Reduce the contact time between the water and the coffee. Try to reduce the contact time between water and coffee in whatever recipe you use.
- Reduce the ratio of your recipe. In other words, use less water per gram of coffee.
Note: The bitterness due to over-extraction is characteristic of medium/dark roasted coffees but rarely occurs in light roasted coffees. Even with very high temperatures and fine grinding, it is difficult to over-extract a light roast coffee.
Influence of the grind on coffee bitterness
We have already mentioned in the previous section that a finer grind than necessary can lead to an over-extraction of the coffee. However, the type of grinder used can also increase the bitterness of the final coffee.
Blade grinders tend to grind in an irregular manner, leaving some pieces larger and others finer. Those finer ground parts will be over-extracted and increase the final beverage’s bitterness.
Note: dark roasted coffees tend to suffer much more from this problem since they are very porous and break easily into small pieces.
Influence of the cleanliness of the coffee maker on coffee bitterness
It is possible that you follow these tips strictly and your coffee still tastes bitter. In many cases, a bad cleaning of the coffee pot and other tools used in the coffee preparation process can produce a bitter taste in the cup.
Espresso coffee makers especially suffer from this problem. Without a thorough cleaning, the previous steps are useless.