Bitterness in coffee – A characteristic that helps round out the flavor

Bitterness in coffee is one of the basic taste sensations we experience, mostly perceived in the mouth and as an aftertaste. It comes from phenolic compounds, primarily chlorogenic acid, which is a significant contributor to bitterness and makes up about 8% of the dry weight of green Arabica beans. According to Verônica Belchior, a Q-grader and researcher, while chlorogenic acid is the main source of bitterness, caffeine also plays a secondary role.

Bitterness exists depending on phenolic compounds

Several factors contribute to bitterness in coffee, including the bean’s natural composition, the roasting process, and growing conditions.

• Natural Composition: The natural compounds in coffee beans, like caffeine and chlorogenic acid, are the primary sources of bitterness. For instance, Robusta beans have significantly higher levels of both chlorogenic acid and caffeine compared to Arabica, making Robusta more bitter. Robusta can contain up to 10% chlorogenic acid, while Arabica contains around 8%, and Robusta has nearly double the caffeine content of Arabica.

• Roasting Process: During roasting, chlorogenic acid breaks down into lactones and phenylindanes. Dr. Thomas Hofmann found that phenylindanes are the main compounds responsible for the sensation of bitterness. Lighter to medium roasts have more lactones, leading to a mild and pleasant bitterness, while darker roasts produce more phenylindanes, creating a harsher, longer-lasting bitterness.

• Growing Conditions: Factors such as altitude, environmental conditions, and production methods can also influence the bitterness in coffee. For example, coffee grown in India tends to have lower levels of chlorogenic acid due to its unique processing methods, such as drying the beans in monsoon winds. Additionally, harvesting beans before they are fully ripe can result in a more bitter taste because unripe beans have higher chlorogenic acid levels.

Natural compounds like caffeine and chlorogenic acid in coffee beans are the primary causes of bitterness

A well-balanced bitterness can elevate the flavor of coffee, creating a fuller and more satisfying mouthfeel. Achieving this balance involves several factors:

• Controlling the Extraction Process: Over-extraction can lead to increased bitterness as more bitter compounds are drawn out. To avoid this, it’s essential to use the recommended grind size for your brewing method. If the grind is too fine, it increases the surface area and prolongs the extraction time, leading to more bitterness. Adjusting the grind size can help control extraction and reduce bitterness.

• Adjusting Water Temperature: Water temperature plays a key role in extraction. Hotter water extracts flavors more quickly, including bitter compounds. If your coffee tastes too bitter, try lowering the water temperature by a few degrees to preserve the delicate flavors while minimizing bitterness.

• Optimizing Brew Time: If coffee is brewed for too long, more bitter compounds are extracted. Be mindful of brew time to prevent over-extraction and excessive bitterness.

• Choosing High-Quality Specialty Coffee: Selecting premium specialty coffee can help reduce bitterness. Specialty coffee generally contains lower levels of caffeine and chlorogenic acid while offering a more diverse flavor profile with a balance of acidity, sweetness, and bitterness. For example, XLIII Coffee offers high-quality specialty coffee that delivers a refined taste, minimizing harsh bitterness and elevating the overall coffee experience.

One of the main causes of bitterness is the coffee extraction process

Conclusion

When you learn to manage and appreciate the factors behind bitterness, you’ll discover that it’s not something to avoid but rather a flavor to be embraced. Like the contrast in a piece of art, bitterness adds depth to coffee, creating a journey that engages the full spectrum of taste sensations.

1. Where does bitterness in coffee come from?

Bitterness in coffee primarily comes from natural compounds like caffeine and chlorogenic acid. The roasting and extraction processes also contribute to varying levels of bitterness as phenylindanes and lactones are formed.

2. Why is Robusta more bitter than Arabica?

Robusta contains higher levels of chlorogenic acid and caffeine compared to Arabica, leading to a more pronounced bitterness. Robusta can have up to 10% chlorogenic acid, whereas Arabica typically contains about 8%, and Robusta’s caffeine content is nearly double.

3. How can I reduce bitterness when brewing coffee?

Controlling the extraction process is key to reducing bitterness. Proper grind size, water temperature, and brewing time help prevent over-extraction and limit bitter compounds.

4. How does roasting affect coffee bitterness?

Light to medium roasts produce more lactones, resulting in a mild and pleasant bitterness. In contrast, dark roasts produce more phenylindanes, which lead to a stronger, more lingering bitterness.

5. Can choosing specialty coffee help reduce bitterness?

Yes, high-quality specialty coffee typically has lower levels of caffeine and chlorogenic acid, offering a balanced and nuanced flavor profile that minimizes unpleasant bitterness while enhancing the overall coffee experience.