Bitterness in Coffee: Understanding Its Causes and Whether It’s Truly Bad? In the world of specialty coffee, bitterness in coffee often carries a negative connotation. Many coffee enthusiasts believe that a well-crafted cup should be sweet, balanced, with a hint of acidity, and ideally not need sugar to improve its taste. However, what exactly contributes to the bitterness in coffee? And is it necessarily something to avoid? Let’s explore the causes of bitterness in coffee and determine if it always deserves its bad reputation.
Bitterness in Coffee: Is It Always a Negative Quality?
Bitterness in coffee isn’t inherently bad. In fact, without any bitterness, your coffee could end up tasting overly sweet or acidic. The real secret lies in achieving balance. A touch of bitterness in coffee adds depth and enhances other flavors without becoming overwhelming.
The issue arises when bitterness in coffee is too dominant. Most of us are more accustomed to overly bitter brews than ones that are too sour, which has given bitterness in coffee an undeservedly bad reputation. Yet, it’s a vital component in creating a well-rounded cup.
That said, excessive bitterness in coffee is undesirable, so let’s dive into what causes it and how to prevent it from overpowering your brew.
Bitterness in Coffee: What Exactly Is It?
We’ve all experienced something bitter before. But the sensation of bitterness in coffee can vary from person to person, as it’s a subjective taste perception. What tastes bitter to one person might not seem the same to another.
It’s also crucial to understand that bitterness in coffee isn’t just about taste. Flavor is influenced by multiple factors, including aroma, environment, emotions, and even music or altitude. While these elements contribute to the overall flavor experience, we’ll focus on the science behind taste for now.
So, let’s dive into the science behind what causes bitterness in coffee. You might want to grab a cup of coffee and settle in!
The Science Behind Bitterness in Coffee
It was once believed that the tongue was divided into distinct taste zones, each responsible for detecting sweetness, saltiness, sourness, and bitterness. However, we now understand that flavor, including bitterness in coffee, is perceived across the entire tongue.
This is due to the sensory cells in our tongues, which contain numerous proteins. According to the US Institute for Quality and Efficiency in Health Care, around 35 of these proteins interact with compounds in food to create the sensation of bitterness.
In coffee, the primary contributors to bitterness are phenolic compounds, particularly chlorogenic acids. These compounds make up as much as 8% of the dry mass of green Arabica beans and play a significant role in the flavor profile of bitterness in coffee.
Of the many types of chlorogenic acids, two are especially important: 5-caffeoylquinic acid, the most common in green coffee, and di-CGA, which is largely responsible for bitterness in coffee.
While chlorogenic acids are the primary source of bitterness in coffee, Verônica Belchior, a Q-grader and PhD student studying the connection between chemical compounds and flavor, notes that caffeine also contributes to bitterness, though it plays a secondary role.
Bitter Green Beans: Exploring the Role of Bitterness in Coffee
When discussing bitterness in coffee, roasting often comes to mind (more on that later!), but certain coffees naturally lean towards more bitterness in coffee due to their composition.
For instance, Robusta coffee is significantly more bitter than Arabica. This increased bitterness in coffee stems from higher levels of chlorogenic acids and caffeine in Robusta. Chlorogenic acids in Robusta can make up as much as 10% of its dry mass, which is 2% more than in Arabica. Additionally, Robusta contains almost double the caffeine content of Arabica, further amplifying the bitterness.
But it’s not just the species or variety that influences bitterness in coffee. A study published by Adriana Farah and Carmen Marino Donangelo in The Brazilian Journal of Plant Physiology in 2006 concluded that factors like species, variety, degree of ripeness, environmental conditions, and agricultural practices all impact the chlorogenic acid content in green coffee beans, thus affecting the overall bitterness in coffee.
The study also highlighted how certain processing methods, such as the Indian monsoon method, reduce both chlorogenic acid levels and the bitterness in coffee. Moreover, Verônica Belchior points out that unripe coffee cherries contain higher levels of chlorogenic acids, contributing to astringency and bitterness in coffee when unripe beans are included in the lot.
Does Roasting Increase Bitterness in Coffee?
Now, let’s dive into the final bit of science behind bitterness in coffee!
During the roasting process, chlorogenic acids begin to break down. While these acids are responsible for the bitterness in coffee, they aren’t inherently bitter themselves. It’s only when roasting converts them into chlorogenic acid lactones and phenylindanes that bitterness in coffee becomes perceptible.
In 2007, Dr. Thomas Hofmann, a prominent researcher, discovered that phenylindanes are the key compounds responsible for creating the bitter taste in coffee. The amount of these compounds varies depending on the roast profile.
Light to medium roasts contain more chlorogenic acid lactones, which Hofmann describes as producing a “pleasant, coffee-like bitter taste.” In contrast, darker roasts generate more phenylindanes, leading to a “lingering, harsher bitter sensation.”
Thus, light to medium roasts tend to have less bitterness in coffee while still maintaining the familiar flavors and aromas we associate with a great cup. However, as we’ve noted, bitterness in coffee is highly subjective. If you find dark roasts too bitter, others might enjoy the richness and depth they offer!
How to Avoid Overly Bitter Brews: Managing Bitterness in Coffee
So, does choosing lightly roasted, high-quality Arabica guarantee that you’ll avoid bitterness in coffee? Not necessarily. The brewing process itself, whether done by you or your barista, plays a significant role in determining the final bitterness in coffee.
To reduce bitterness in coffee, it’s important to avoid over-extracting it. Bitterness tends to intensify later in the brewing process. Several factors affect extraction, such as brewing method, grind size, water temperature, and brew time. Fortunately, there are general tips to follow to help prevent excessive bitterness in coffee.
First, ensure you’re using the right grind size for your brewing method. A finer grind increases the surface area, potentially over-extracting flavors and causing bitterness in coffee. With methods like drip or pour-over, a finer grind also prolongs brew time, leading to more extraction.
Next, consider your water temperature. Hotter water extracts flavors and aromas more efficiently. If your coffee is too bitter, try lowering the water temperature by a couple of degrees to reduce bitterness in coffee.
Lastly, pay attention to brew time. If your coffee has a bitter edge, it may be brewing too long.
Keep in mind that brewing is a balancing act. Adjusting one factor, such as grind size, can influence another, like brew time, so experiment carefully to minimize bitterness in coffee.
Bitterness in coffee isn’t inherently negative, but when it overshadows all other flavors, it becomes an issue. Thankfully, as we deepen our understanding of the chemical compounds responsible for bitterness, we’re gaining better insights into how to manage and control its development and extraction.