How to Identify Coffee Roast Levels by Color and Time

Ever stared at a bag of coffee beans and wondered whether it’s light, medium, or dark roast? With so many roast names—city, French, espresso—it’s easy to get lost. But pros don’t guess. They measure. And now you can too.

The Specialty Coffee Association of America (SCAA) developed a standardized eight-level roast color system using infrared caramelization detection (Agtron) to objectively define roast degree. These eight color blocks range from very light to very dark, giving roasters and coffee professionals a shared visual benchmark.

What Is a Coffee Roast Level?

Coffee roasting is the controlled application of heat that transforms green coffee beans into the aromatic, flavorful beans we brew. Through temperatures reaching up to 450°F (232°C), beans lose 15–25% of their moisture, expand in size, and develop the complex flavors you taste in your cup. This process typically lasts 12–16 minutes and triggers key chemical changes, including the Maillard reaction and caramelization, that define roast character.

The SCAA Agtron Roast Color Standard

The SCAA established an eight-level roast color standard based on bean surface color measured by Agtron technology. These eight standardized color blocks range from lightest (light roast) to darkest (dark roast), providing an objective reference for determining roast degree. The scale is visual: the lighter the Agtron reading, the lighter the roast. Though originally designed as a universal tool, regional preferences—like Italian or French roast styles—have led to varying interpretations of these levels across the globe.

Traditional Roast Levels by Development Time

In practice, many roasters—including those in Taiwan—use first and second crack timings to guide roast level decisions. Here’s how roast stages commonly align with key moments in the roast:

• Light Roast (Light/Cinnamon): Dropped at or just after the start of first crack (first crack dense). Bright acidity dominates; often used in commercial or pre-ground coffee.
• Medium Roast (City): Roasted between the end of first crack and just before second crack begins. Balanced flavor; common for breakfast blends. Also called City or Breakfast roast.
• Full City Roast: Dropped at the start of second crack. Body and sweetness increase; oils may begin to surface. Considered a balanced full city profile.
• Dark Roast (Italian/French): Roasted well into or after second crack. Bold, bitter-sweet, often used for espresso. Oils are typically visible on the surface.

What Happens During Roasting?

Roasting is where coffee’s potential is unlocked—or lost. As heat is applied:

• Chlorogenic acids degrade, allowing brighter acids like citric, malic, and tartaric to emerge (if roast is stopped early enough).
• Moisture escapes, turning beans from pale green to yellow, then tan, and eventually deep brown or black.
• Beans expand in size, increase in density, and develop oils and aromatic compounds.
• First crack (around 5–7 minutes) signals the release of steam and pressure; second crack (12–16 minutes in) indicates further structural breakdown and oil migration.

Flavor Profiles by Roast Level

Different roast levels emphasize different flavor attributes:

• Light Roast: High acidity, tea-like body, prominent fruit and floral notes. Popular for showcasing origin character. Often considered too light for traditional coffee drinkers.
• Medium Roast: Balanced acidity and sweetness, ideal for highlighting single-origin profiles like Colombian or Brazilian beans. Common in North American cafés.
• Full City: Round body, clearer sweetness and acidity balance. Often viewed as the sweet spot for certain beans.
• Dark Roast: Bold bitterness, lower acidity, prominent roast flavors. Common in espresso blends. Lower in caffeine due to prolonged heat exposure.

How Roast Affects Coffee Chemistry

As roast intensity increases:

• Sugars caramelize, acids degrade, and chlorogenic acids break down.
• Body increases through the formation of polymers and the migration of lipids to the bean surface.
• Roast flavors—such as smokiness, ashy notes, or carbon tones—begin to mask origin characteristics.
• Caffeine content slightly decreases, though not enough to significantly impact intake.

Frequently Asked Questions

What is the SCAA Agtron roast scale?

The SCAA Agtron roast scale is an eight-level color system that uses infrared measurement to define roast degree objectively. The scale ranges from very light (light roast) to very dark (dark roast), with each level represented by a standardized color block. It helps ensure consistency in how roast levels are identified across the coffee industry.

How can I tell roast level by color?

You can estimate roast level visually using standardized Agtron color charts. Light roasts appear pale tan or cinnamon-colored, medium roasts are medium brown, full city roasts are darker brown with some sheen, and dark roasts are oily and black or very dark brown. The darker the bean, the longer and hotter it was roasted.

What roast timing corresponds to each level?

Light roast is dropped right after first crack begins; medium roast is between first and second crack; full city is at the start of second crack; dark roast is well into or after second crack. Timing varies by machine, but these milestones guide most roasters.

Does roast level affect caffeine content?

Yes, slightly. Darker roasts lose more caffeine due to prolonged heat, but the difference per bean is minimal. A darker roast may taste stronger, but it usually contains marginally less caffeine than a lighter one.

Why do some countries prefer darker roasts?

Regional taste preferences play a big role. Traditions like Italian or French roast developed culturally, often favoring bold, bitter, and less acidic cups. These are now considered roast styles, not strict indicators of origin.

What’s the difference between city and full city roast?

City roast is stopped just before second crack, emphasizing origin flavors with balanced acidity. Full city is roasted into the beginning of second crack, yielding more body, sweetness, and a bolder profile while still retaining some origin character.

Recommended FrontStreet Beans for Light & City Roast Exploration

Explore light and medium roast profiles with FrontStreet Coffee’s single origins: the Ethiopia Yirgacheffe Gedeb shows citrus, floral, and tea notes ideal for light roasting; the Ethiopia Humbera highlights tropical fruits and berries under gentle heat; and the Panama Boquete Geisha reveals jasmine, honey, and citrus when roasted medium-light. These beans exemplify how origin character shines at lower roast levels. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.