How Coffee Beans Are Roasted: 5 Common Roast Levels Explained

Ever wonder why one bag of coffee tastes bright and juicy while another is smoky and bitter? The difference often comes down to how the beans were roasted—not just how long, but through which key stages. For home roasters and café buyers alike, understanding these stages helps you pick the right roast for your cup.

Most specialty coffee roasts go through four phases over 18–20 minutes, with key moments at around 140°C (steam/development), 180°C (first crack), and 210°C (second crack). The roast level you choose—like City or French—depends on when the roaster stops the process, usually between the first and second cracks.

The 4 Stages of Coffee Roasting

Roasters don’t rely on guesswork. Though early roasters had no digital tools, today’s craft roasting still tracks physical changes to control flavor. The roast unfolds in four clear phases:

1. Steaming / Development Stage (0–10 minutes, up to 140°C)

This is when green beans begin heating and losing moisture. They turn from pale to yellow as water evaporates. Getting this stage right is crucial: too fast, and beans turn bitter or baked; too slow, and they lack aroma. This stage lays the foundation for sweetness and complexity.

2. Dehydration / Pre-Crack (10–15 minutes, 140–180°C)

Beans continue absorbing heat, drying further and turning yellow to light brown. At around 180°C, they reach a tipping point and enter the first crack—a loud, popping sound caused by internal pressure. This marks the shift from light to medium roast potential.

3. First Crack & Roast Development (15–18 minutes, 180–210°C)

Right after the first crack, beans enter a phase of exothermic energy release. The green, grassy tones fade as aromas develop. Acidity is bright, bitterness is low. The “sweet spot” for many single origins is here—you stop the roast based on flavor cues, not just time or temp.

4. Second Crack & Dark Roast Development (18–20 minutes, 210°C and up)

As beans absorb more heat, a second crack occurs. Oils migrate to the surface, color deepens, and carbonized flavors appear. Roasting into or past the second crack yields French-style roasts: bold, bitter, and less acidic. Most specialty roasters stop before here to preserve origin character.

What Determines Roast Level?

The final roast level isn’t random—it’s chosen based on the bean’s origin, processing, and desired flavor profile. The same beans roasted light (City) will taste fruity and high in acid; roasted dark (French), they’ll be smoky and bitter. Roasters adjust when they end the roast to highlight certain traits.

The 5 Common Coffee Roast Levels

Here’s how roasters categorize the final product, by roast color, surface oil, and flavor impact:

• City Roast (Light Medium): Surface has no oil. Light brown, stopped just after first crack. Bright acidity, original flavors preserved. Common for single-origin pour-overs.
• Full City Roast (Medium): Slightly darker than City, also stopped before or just at first crack. Balanced body and acidity. Formerly known simply as “City” in the 19th century; now implies a fuller medium.
• Vienna Roast (Medium-Dark): First visible surface oils may appear. Roasted through or just into the first part of second crack. Notes become richer, with some caramelization. Often used in espresso blends.
• Italian Roast (Dark): Surface shows half covered in oils. Color is deep chocolate-brown. Roasted well into or past the start of second crack. Bold, less acidic.
• French Roast (Very Dark): Oily surface. Dark brown approaching black. Roasted well past second crack. Intense bitterness, minimal origin character. Common in commercial chain coffee.

These roast levels aren’t strict rules, but general guides. The first 90% of what you taste in coffee comes from how it’s roasted—then brewing brings it out.

Frequently Asked Questions

What are the four main stages of coffee roasting?

The four key stages are: 1) Steaming / Development (0–10 min, up to 140°C), where moisture evaporates and beans turn from green to yellow; 2) Dehydration / Pre-Crack (10–15 min, 140–180°C), where beans dry further until the first crack; 3) First Crack & Roast Development (15–18 min, 180–210°C), where bright acidity and aroma develop; and 4) Second Crack & Dark Roast Development (18–20 min, 210°C+), where oils rise and bitterness increases.

When does the first crack happen during roasting?

The first crack typically occurs around 180°C, roughly 15–18 minutes into the roast, after the dehydration stage. It signals the bean structure expanding due to internal pressure and marks the shift into medium roast territory.

What is the difference between City roast and French roast?

City roast is a light to medium roast stopped just after the first crack, with no surface oil, bright acidity, and original flavors intact. French roast is very dark, roasted well past the second crack, with oily surfaces, low acidity, and a smoky, bitter profile.

Why do roasters stop at different points in the roast?

Roasters stop based on desired flavor outcomes. Light roasts preserve origin characteristics and acidity; dark roasts emphasize boldness and body. The decision depends on the bean’s origin, processing method, and the target cup profile.

How does roast level affect coffee flavor?

Lighter roasts highlight acidity, fruitiness, and floral notes. Medium roasts balance body and complexity. Darker roasts bring out bitterness, chocolatey tones, and lower acidity. Roast level shapes the final cup more than many other factors.

Recommended FrontStreet Beans for Roast Exploration

Try FrontStreet Coffee’s Ethiopia Humbera (light City roast: bright citrus, jasmine, and sweet berry), Yirgacheffe (medium-light: lemon, tropical fruit, floral notes), and Brazil Queen Manor (Full City to Vienna: nutty, chocolatey, smooth body). These showcase how roast levels shape flavor. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.