An Introduction to Coffee Roasting

Coffee's charm lies in our continuous quest to discover the ideal roasting method that best accentuates its unique characteristics. Among coffee processing methods, roasting is arguably one of the most influential steps, where raw green beans are transformed into flavorful beans ready for brewing. The primary objective of roasting is to develop aroma and flavor by triggering a series of chemical reactions—such as heat degradation, the Maillard reaction, and caramelization—which produce various combinations of sugars and acids. Similar reactions occur in bread and cookie baking, creating complex and delightful flavors we enjoy.

Understanding the roast level and its corresponding color helps us choose coffee beans that match our personal tastes. Nowadays, coffee roast levels are commonly classified into light, medium, and dark roasts. Before the third-wave coffee revolution, terms like "City roast," "French roast," "Italian roast," or "Viennese roast" were more prevalent. However, these terms are rather broad and lack precise standardized definitions.

Choosing the roast level remains largely a matter of personal preference. Just as some people prefer their steak medium-rare while others favor well-done, coffee enthusiasts have their individual tastes. If dining at a five-star restaurant, one might trust the chef's expertise to present the meat in its optimal form. Similarly, specialty coffee roasters possess the skill and judgment to determine the roast degree that best highlights the beans' intrinsic characteristics. Each roaster develops distinct roasting profiles to achieve this goal, often describing their coffees by the overall flavor they create through roasting.

Roast Levels

Light Roast

Light roasting is commonly used for single-origin coffees and was historically known as "Cinnamon Roast" due to its cinnamon-like color. Lightly roasted coffee typically features high acidity, lighter body, and sometimes fruit-like sweetness. Because of its lower saturation, adding milk can sometimes mask the coffee's flavors. However, if floral, fruity, or distinctly acidic notes are prominent, these flavors can persist even after adding milk. For example, a coffee with prominent apple notes, when combined with milk, might resemble the taste of apple-flavored milk. Thus, certain lightly roasted coffees do pair exceptionally well with milk.

Medium Roast

Medium roast beans generally do not display oil on their surface. They offer a harmonious balance between chocolate-like bitterness and full-bodied richness. Medium-roasted coffee, particularly in espresso preparations, can yield bittersweet chocolate flavors, and when combined with milk, the resulting beverage often tastes reminiscent of milk chocolate. Medium roasts are thus frequently chosen for espresso and cappuccino. Slightly darker than medium roast is termed "City Roast," falling into the medium-dark roast category.

Medium-Dark Roast

Commonly referred to as "Viennese Roast" in American terminology, medium-dark roasts are slightly darker than medium roasts, exhibiting dark brown beans with visible oil spots. Another common term for this roast is "Light French Roast."

Dark Roast

Dark-roasted beans appear very dark brown to nearly black and have an oily surface. These beans exhibit pronounced bitterness. French Roast beans typically show a dark chocolate color, while Italian Roast beans are almost entirely black and have an exceptionally oily surface. Dark roasts are commonly found in chain coffee stores and are particularly suited for milk-heavy beverages like lattes.

Coffee Roast Trends and Preferences

While there's global agreement on the broad definitions above, there's no consensus on the universally ideal roast degree—it is partly influenced by fashion trends. During the second wave coffee movement, roast levels grew progressively darker, possibly due to the rising popularity of espresso-based drinks. Another explanation suggests darker roasts can yield a more consistent and bold coffee flavor, favored in chains or affordable coffee shops.

Historically, dark roasting was initially intended to mask defects and off-flavors in coffee beans when storage conditions and resources were limited. Today, dark roasting provides an opportunity to emphasize certain desirable characteristics of high-quality beans.

With the advent of the third-wave coffee movement, cafes have become less confined to dark roasting methods and are embracing lighter roasting profiles. Contemporary coffee enthusiasts enjoy unprecedented accessibility to diverse coffee styles and approach each variety with openness, ultimately selecting beans that best match their individual palate preferences.