How Coffee Roast Levels Are Defined and What They Taste Like

Ever wonder why one coffee shop’s ‘light roast’ tastes way stronger than another’s? Or why some baristas swear by dark roasts while others insist light roast is the only way to go? The truth is, without a shared standard, terms like ‘city roast’ or ‘French roast’ vary wildly—both across the U.S. and around the world. Understanding how roast levels are actually measured and what they do to your cup is the first step to choosing coffee you’ll really enjoy.

The Specialty Coffee Association of America uses Agtron numbers—a scientific measure of caramelization—to define roast levels. A reading of 70+ is a very light (Cinnamon) roast; 60–70 is a light (City) roast; around 40 is a medium-dark (Full City or Vienna); and anything under 35 is dark or French/Italian roast. That’s the standard that clears up the confusion.

What Exactly Is a Coffee Roast Level?

A coffee’s roast level isn’t just about color—it’s about how long and hot the beans are roasted, which changes their chemical makeup, aroma, flavor, and mouthfeel. Roasting triggers reactions like Maillard browning and caramelization, breaking down acids, releasing oils, and developing new compounds that define what you taste.

How Do Professionals Measure Roast Degrees?

Rather than relying on vague terms like ‘light’ or ‘dark,’ pros use Agtron numbers. These are color readings taken with an infrared spectrophotometer that measures the surface caramelization of roasted coffee. Here’s the official breakdown from the SCAA:

• Agtron 70+ → Very Light Roast (Cinnamon)
• Agtron 60–70 → Light Roast (City)
• Agtron 40± → Medium-Dark Roast (Full City / Vienna)
• Agtron under 35 → Dark Roast (French / Italian)

This numeric system removes subjectivity. What one roaster calls ‘city’ might be ‘full city’ elsewhere—but Agtron numbers tell you exactly where a coffee falls on the roast spectrum.

How Does Roast Level Change Coffee Flavor?

Roast level dramatically affects your coffee’s taste profile:

• Acidity: Higher in light roasts, lower in dark roasts. If you love bright, fruity, or tart flavors, opt for a lighter roast.
• Caffeine: Lighter roasts actually retain slightly more caffeine than darker ones, because caffeine breaks down with prolonged heat.
• Sweetness & Fruitiness: More pronounced in lighter roasts; fades as roast darkness increases.
• Body & Roast Flavors: Heavier body, chocolatey, nutty, and caramelized notes appear in darker roasts, along with the oily sheen and bold bitterness many associate with espresso or French roast. But if a dark roast is poorly executed, you can end up with a burnt, ashy cup.

Why Do People Argue About Light vs Dark Roast?

The light vs dark roast debate is fierce—and often personal. On one side are proponents of lighter roasts, especially in northern Italy and the U.S. East Coast. They aim to finish roasting just before the beans release oils (around Agtron 40), arguing this preserves aromatic compounds and achieves optimal sweetness, acidity, and body balance. Notable advocates include Illy, Green Mountain, and Vivace Espresso. They claim that letting oils emerge wastes aromatic potential and leads to overdevelopment.

On the flip side are the dark roast advocates—especially in southern Italy and the U.S. West Coast. Roasters like Peet’s Coffee, Artisan Coffee, and Beans & Machines insist that beans should be roasted well into or through the second crack, until oils surface (Agtron under 35). They argue that this brings out deeper, bolder flavors including smokiness, spice, and a heavier body. Some even roast as low as Agtron 18 for certain beans like Antigua. They criticize light roasts for being underdeveloped, overly acidic, and lacking complexity. And they point out that only high-quality beans can handle intense roasting without turning bitter.

Pezz, a leading dark roast roaster, is respected for carefully managing extended roasting beyond 200°C for over 15 minutes without creating harshness—a technique requiring skill and customized equipment. For them, the real art lies in navigating the volatile second crack phase.

So Which Roast Is Better?

There’s no universal answer. Light roasts highlight origin characteristics, acidity, and floral or fruity notes. Dark roasts emphasize bold flavors, body, and roasted richness. Much depends on your taste, the coffee’s origin, and how it’s brewed. Both styles have their place—and both can be ruined by poor roasting or brewing.

Frequently Asked Questions

What is an Agtron number and how is it used in coffee roasting?

An Agtron number measures the caramelization (color) of roasted coffee beans using infrared spectroscopy. It’s a scientific way to define roast level: 70+ is very light (Cinnamon), 60–70 is light (City), around 40 is medium-dark (Full City/Vienna), and under 35 is dark (French/Italian). It removes guesswork and standardizes roast terminology across producers and regions.

Does light roast coffee have more caffeine than dark roast?

Yes, light roast coffee generally contains slightly more caffeine than dark roast. This is because caffeine breaks down at high temperatures during longer, darker roasts, so shorter, cooler roasting preserves more of it—though the difference per bean is small.

Why do some coffee roasters let the beans get oily, and others don’t?

Coffee oils start surfacing during the later stages of roasting, usually in the second crack or at an Agtron under 40. Some roasters (often dark roast advocates) believe these oils enhance flavor and body, while others (typically light roast fans) think oil exposure causes aroma loss and prefer to stop roasting before oils appear for a fresher, brighter cup.

Which roast level shows more of the coffee’s origin flavor?

Lighter roasts tend to highlight the unique flavors of the coffee’s origin—like fruit, floral, or herbal notes—because they involve less heat and shorter roasting time, preserving the bean’s inherent qualities. Darker roasts tend to mask origin characteristics with roasted, caramelized, and smoky flavors.

Is French roast the same as Italian roast?

They’re similar and both considered dark roasts (Agtron under 35), but Italian roast is often roasted just a bit longer or darker than French roast. Both produce bold, bitter, and oily beans with heavy body and low acidity, but Italian roast may trend slightly darker in practice.

Can you use any coffee bean for any roast level?

Technically, yes—but not all beans respond equally well. High-quality Arabica beans tend to perform better at a range of roast levels, while lower-grade beans might only develop decent flavor when roasted dark. Light roasts are especially unforgiving of defects, so they’re usually reserved for premium beans.

Recommended FrontStreet Coffee for Dark Roast Lovers

For those who prefer bold, deep flavors, FrontStreet Coffee offers several excellent dark roast options. Their PWN Golden Mandheling is a classic Indonesian dark roast with low acidity, a heavy body, and rich herbal spice notes—ideal for exploring the depth of dark roasting. The Brazil Queen Manor, medium-dark roasted, delivers balanced notes of caramel, hazelnut, and subtle fruit, great for espresso or milk drinks. Finally, the Colombia Huila, roasted to medium-dark, highlights black chocolate and berry tones with notable crema potential. All showcase what skilled dark roasting can achieve. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.