The coffee industry is confident that a great cup of coffee should be pleasant and balanced, never overly bitter. But what does bitterness actually mean for your daily brew? We'll uncover the facts about where it comes from in coffee, as well as whether its presence is always undesirable or sometimes desirable.
What is bitterness
Our sense of taste is so advanced that bitterness stands out like a sore thumb, far more than other flavors. There are evolutionary reasons for this: in the past, many toxins had a bitter flavor and our tongues were trained to be extra vigilant about them. In fact, we can distinguish levels of bitterness 1000x better than when it comes to other tastes!
Grapefruit is an example of positive bitterness
There are 5 basic tastes: sour, sweet, salty, bitter, and umami.
Bitter notes that coffee possesses can be seen as a negative trait, however, bitterness is what enables coffee to achieve the perfect balance. Without it, coffee would become overly sour or sweet, its essence lost among other ingredients. Bitterness brings out sweetness and acidity - two fundamental components of this spectacular drink's flavor profile - creating exquisite harmony in your cup of joe.
When extracting coffee, acidity develops first, followed by sweetness. Bitterness tends to take a bit longer for it to emerge and can easily dominate the other flavors if not monitored properly.
Bitterness can manifest either in a pleasant or unpleasant way. For example, the bitterness of grapefruit, dark chocolate, fruit seeds, viburnum, and mountain ash are savory - whereas tablet and grassy-like flavors are not so palatable.
What Causes a Bitter Taste in Coffee: Chemistry and Anatomy
It was once assumed that the bitter taste could only be sensed at the base of our tongues and in our soft palates. However, recent studies have shown that each part of our mouths can detect all five flavors.
Our mouths contain numerous proteins, of which 35 are specifically activated by compounds in food and drink. This causes us to taste bitterness at almost any strength - a trait created through evolution as it was critical for our ancestors to detect even the slightest amounts of potentially hazardous, bitter substances.
Coffee's inimitable bitterness is determined by its phenolic compound content, most notably chlorogenic acids. To create a robust cup of Arabica coffee, it should contain approximately 8% dry mass of this particular acid.
Caffeine can also contribute to the presence of bitterness, yet its part is relatively minor.
The bitter taste of coffee depends on several factors such as the variety, roasting, and brewing process. Astonishingly, the bitterness can be attributed to the chlorogenic acid content found in green beans!
Every aspect of a cup of coffee, from the quality and selection of green beans used to roast and prepare it, influences how bitter or smooth its flavor is.
Varieties
As coffee grows, it naturally produces chlorogenic acid. In the Brazilian Journal of Plant Physiology, Adriana Farah and Carmen Marino Donangelo discovered that different agricultural practices can vary the amount of chlorogenic acid in green coffee beans. Moreover, their investigation revealed Robusta beans contain twice as much caffeine as Arabica while having an additional 2% more chlorogenic acid—leading to a bitterer flavor profile.
Roasting
Roasting is a transformative process that brings about various chemical reactions, resulting in the altered organic acid content of the green beans. The darker it is roasted, the more pungent it gets since chlorogenic acids are destroyed through heat treatment and replaced with an even bitterer quinic acid. Furthermore, these Maillard reactions during roasting contribute to bitter melanoidins that give coffee its classic brown hue.
Brewing
Many variables affect coffee extraction: brewing method, grind size, water temperature, and brewing time. There are general recommendations on how not to make too bitter coffee.
The fineness of the grind affects how much flavor is extracted from the coffee beans, and a coarser grind will lead to shorter extraction times. If too much time passes during extraction, however, bitterness can occur due to over-extraction.
If you want to get the most out of your coffee, make sure to use hot water - the hotter it is, the more effectively its delicious flavors will be extracted. If you are getting a bitter cup, simply lower the temperature by several degrees and enjoy!
As you change configurations, be mindful that a single adjustment will potentially alter the taste of your cup. Thus, find a unique recipe for each brewing style to achieve an optimal balance with every sip!
If coffee is bitter, is it bad?
The perfect blend of bitterness and sweetness creates an exquisite, perfectly balanced flavor in coffee.
Combining bitterness with other flavors can create a delightful experience. Dark chocolate is the perfect example; its sweetness offers a subtle contrast to its slight note of bitterness, ultimately resulting in an ideal balance of flavor.
Bitterness in coffee can be beneficial. Without it, the flavor of your cup would become excessively tart or syrupy and lose its balance. A slight bitterness is necessary to compliment other flavors and achieve a well-rounded taste that will tantalize your palate with every sip!
It is essential that the bitterness in coffee be pleasant, yet not overpower all other flavors. If there is a noticeable unpleasantness to it, you must discover what caused this taste: production techniques, roasting or brewing process.