Coffee Roasting: The Difference Between Dark and Light Roast & Characteristics of Japanese-Style Dark Roast Coffee

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Understanding Coffee Roasting: The Key to Flavor Balance

The flavor of coffee is primarily composed of bitterness and acidity. But where do these flavors originate? Moreover, why does the balance between bitterness and acidity change with different roasting levels? FrontStreet Coffee believes that coffee roasting degree plays a crucial role in this process. Let's explore the knowledge of coffee roasting.

What is Coffee Roasting?

Coffee roasting refers to the process of roasting coffee beans. When coffee beans are heated and roasted, their components undergo chemical changes, developing the familiar colors, aromas, and flavors we recognize in coffee.

Roast Level Names and Classifications

The indicator of heating degree becomes the roast level. Roast levels can be broadly divided into three stages: light roast, medium roast, and dark roast. To further细分风味差异, in Japan, roasting degrees are classified into eight levels from extremely light roast to Italian roast.

Light Roast

When generally discussing light roasts, it refers to extremely light roast and light roast.

Medium Roast

Medium roast refers to medium roast, medium-dark roast, and city roast.

Dark Roast

Dark roast refers to dark roast, French roast, and Italian roast.

Generally, light roast coffee beans have a cinnamon-colored surface with strong acidity and slight aroma; medium roast coffee beans have a chestnut-colored surface with light taste,偏向酸带苦, moderate aroma, preserving the original flavor of coffee beans, often used for American coffee or blended coffee; medium-dark roast beans have light brown surface with bright and lively taste, balanced acidity and bitterness with lighter acidity, releasing the quality flavors in coffee, serving as the standard roast level and the most popular among the public; extremely dark roast beans have black surface with oily sheen, before the coffee bean fibers carbonize, with strong and complex taste, powerful bitterness, with rich roasting and burnt aroma, mainly popular in Italy, often used for Espresso.

Dark roasted coffee beans have a heavier color, meaning the brewed coffee will be darker. In terms of taste, because of the heavy roasting degree, the acidity will decrease but the flavor will be more bitter. Medium roast will have moderate taste with medium acidity and bitterness. Similarly, if it's light roast, the taste will definitely be more acidic with strong acidity but less intense bitterness. This means the degree of coffee bean roasting affects its acidity and bitterness - the heavier the roast, the more bitter; the lighter the roast, the more acidic.

FrontStreet Coffee believes that no roast degree is better than another - it completely depends on personal preference. Cafes like Starbucks and other representatives of the second coffee wave tend to choose flavors brought by dark roasting. Generally, light roast beans have more lively and bright acidity, while dark roast beans have richer body and stronger nutty flavors.

Different roasting degrees also affect the changes in chemical elements within coffee. Renowned coffee master Mamoru Taguchi discussed in his book that the roasting process causes chlorogenic acid in coffee to produce bitter substances, and these substances vary with different roasting degrees. This is why most light roast coffee beans present bright and refreshing flavors while dark roasts present richer bitter flavors.

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