Why coffee has a bitter aftertaste

That bitter aftertaste that lingers in your mouth after sipping an espresso is not always a flaw. In some blends, bitterness is a distinctive feature, part of the sensory profile. But when it becomes too intrusive or unpleasant, it is a sign that something – in the blend, roasting or preparation – could be improved.

In this article, we look at the main causes of bitterness in coffee and tips for balancing it correctly in the cup.

Influence of the blend and roasting

The first factor that affects the degree of bitterness in coffee is the type of blend. Blends with a high percentage of Robusta tend to be more bitter than those made from 100% Arabica. This is because Robusta contains more caffeine. Its strong, full-bodied taste is perfect for those who love a strong espresso, but it can be excessive for those looking for sweetness and delicacy.

Roasting also plays a crucial role. Very dark roasting, used to obtain a strong and persistent coffee, promotes the development of bitter and toasted notes. During the process, the sugars in the beans caramelise and then burn, turning into bitter substances. If the roasting is not well controlled or uniform, the effect can be even more pronounced.

Portioli blends are designed to ensure a perfect balance between body, aroma and aftertaste, thanks to a careful selection of beans and single-origin roasting.

Preparation errors that increase bitterness

Even with a well-balanced blend, bitterness can emerge due to errors in the preparation. The first is grinding too finely, which slows down extraction and causes the water to ‘stress’ the coffee powder, extracting the bitter components excessively.

Another factor is water that is too hot. Temperatures above 94°C can alter the chemistry of the extraction, increasing bitterness, especially with blends with a high percentage of Robusta. The same applies to excessive extraction time: an espresso that takes too long to come out may contain more undesirable substances, including the most bitter ones.

Poor cleaning of the coffee machine can also contribute to an unpleasant taste. Residues of old coffee, rancid oils and limescale can compromise the result in the cup, leaving a bitter and dull aftertaste.

How to rebalance the taste in the cup

The good news is that bitterness can be controlled and rebalanced. First of all, choose a blend that suits your palate: if you prefer a smoother taste, go for blends with a higher percentage of Arabica. Portioli offers a range of solutions in beans, ground coffee, capsules and pods to suit every need.

Then check that your equipment is set up correctly: check the water temperature, the pressure of the machine, the dose of coffee and the degree of grinding. Even a slight change can significantly improve the final taste.

Finally, take care of maintenance and cleaning: a well-cleaned machine brings out the best in every blend. If you enjoy a sweeter touch, try pairing your coffee with a shortbread biscuit or a Portioli chocolate. This delightful combination softens the bitterness while preserving the authentic espresso experience.