Walk into any specialty coffee roaster and you'll encounter terms like "light roast," "medium roast," "city roast," "full city," and "French roast." The terminology can be confusing, and the implications for flavour are significant. Understanding roast levels helps you choose beans that match your taste preferences and brewing method. In this guide, we'll demystify coffee roasting and help you navigate the spectrum from light to dark.
What Happens During Roasting
Green coffee beans are the seeds of the coffee cherry, dried but otherwise unprocessed. They smell grassy and vegetal, nothing like the aromatic coffee we know. Roasting transforms these seeds through a complex series of chemical reactions triggered by heat.
As beans heat up, moisture evaporates, and the Maillard reaction—the same process that browns bread and sears steaks—creates hundreds of aromatic compounds. Sugars caramelise, acids transform, and cellular structures break down. The longer and hotter the roast, the more pronounced these changes become.
Roasters listen for two key events called "cracks." First crack occurs around 196°C (385°F) when steam pressure causes beans to expand and pop audibly. Second crack, around 224°C (435°F), signals the breakdown of the bean's cellular matrix. The roaster's decisions about when to end the roast relative to these cracks determine the final roast level.
Light roasts end shortly after first crack. Medium roasts develop further between first and second crack. Dark roasts push into or beyond second crack. The window between cracks—typically just one to two minutes—represents the critical decision zone for roasters.
Light Roast Characteristics
Light roast coffee, sometimes called "cinnamon roast" or "blonde roast," is pulled from the roaster shortly after first crack. The beans appear light brown with a matte, dry surface—the oils remain locked inside the bean's structure.
Flavour Profile
Light roasts preserve the bean's origin characteristics most clearly. You'll taste the terroir—the specific flavours imparted by the coffee's growing region, altitude, processing method, and variety. Ethiopian naturals might present blueberry and wine notes. Kenyan coffees often show bright citrus and black currant. Colombian beans might offer caramel and stone fruit.
Acidity is pronounced in light roasts. This isn't the harsh, stomach-churning acidity of over-extraction but rather a pleasant brightness similar to citrus fruits or wine. Light roasts also tend toward floral and tea-like qualities, with complex, layered flavours that reward attention.
Best Brewing Methods
Light roasts shine in brewing methods that highlight clarity and complexity: pour over, AeroPress, and drip coffee. The extended contact time and paper filtration of these methods showcase the nuanced flavours light roasting preserves. Some specialty cafes use light roasts for espresso, though they require adjusted parameters and produce a very different character than traditional espresso.
Medium Roast Characteristics
Medium roast—also called "city roast" or "American roast"—represents the middle ground, stopped between first and second crack. The beans are a warm, medium brown with a mostly dry surface, though you might see slight oil at the edges.
Flavour Profile
Medium roasts balance origin character with roast-developed flavours. You'll still taste some regional characteristics, but they're complemented by sweetness from caramelised sugars and a more rounded body. Chocolate and nut notes often emerge, alongside fruit flavours that have softened from bright and acidic to jammy and sweet.
Acidity is present but mellowed. The cup has more body than light roasts, with a satisfying weight on the palate. This balance makes medium roasts widely appealing—they're flavourful and complex without being challenging.
Best Brewing Methods
Medium roasts are incredibly versatile. They work beautifully for drip coffee and pour over, perform well in espresso, and can even handle French press without becoming overpoweringly bitter. If you're uncertain about preferences or buying for a group, medium roast is the safest choice.
Many specialty roasters offer "espresso roasts" that are actually medium roasts optimised for espresso extraction. These produce balanced shots with enough body for milk drinks but sufficient complexity to enjoy straight. They represent the modern approach to espresso, distinct from the very dark roasts traditionally associated with Italian espresso.
Dark Roast Characteristics
Dark roast coffee is roasted into or beyond second crack. Names like "French roast," "Italian roast," "Vienna roast," and "espresso roast" (traditional usage) indicate dark roasting. The beans appear dark brown to nearly black, with an oily, shiny surface as the internal oils migrate outward.
Flavour Profile
Dark roasting fundamentally transforms the bean. Origin characteristics largely disappear, replaced by flavours created through the roasting process itself. Expect smoky, bitter, and burnt sugar notes. Some people describe dark roasts as having chocolate or caramel flavours, though these are different in character from the sweetness of medium roasts—more bittersweet and intense.
Acidity is minimal to absent. The mouthfeel is full and sometimes described as "syrupy." Dark roasts taste most prominently of "coffee" in the traditional, robust sense. They're bold, uncomplicated, and assertive.
Best Brewing Methods
Dark roasts work well for espresso (particularly traditional Italian-style), moka pot, and French press—methods that emphasise body over clarity. They're also the go-to for milk-based drinks where you want the coffee flavour to punch through dairy. Avoid using dark roasts for pour over or other filter methods, where their lack of complexity becomes apparent and bitter notes can dominate.
The Caffeine Myth
A persistent myth claims that dark roast coffee has more caffeine because it tastes stronger. In reality, the opposite is marginally true—roasting does degrade caffeine slightly, so light roasts retain fractionally more. However, the difference is negligible in practical terms.
What matters more is how you measure your coffee. Dark roasted beans weigh less than light roasted beans (they've lost more moisture), so if you measure by weight, you'll use more dark roast beans for the same weight, potentially getting more caffeine. If you measure by volume, the larger, puffier dark roast beans might give you less caffeine per scoop. These differences are minor—don't choose roast level based on caffeine content.
If caffeine sensitivity is your concern, consider the coffee species instead. Robusta beans contain roughly twice the caffeine of Arabica beans. A light roast Robusta will have significantly more caffeine than a dark roast Arabica.
Specialty Coffee and Roast Trends
The specialty coffee movement has shifted preferences toward lighter roasts over the past two decades. This reflects both changing tastes and advances in sourcing. When coffee is exceptional—carefully grown, processed, and transported—roasters want to preserve its unique characteristics rather than mask them with roast flavour.
However, this doesn't mean dark roasts are inferior. For certain applications and preferences, they're ideal. Traditional espresso culture, particularly in Italy and southern Europe, favours darker roasts. Many people genuinely prefer the bold, straightforward flavour of dark roasted coffee. There's no objectively "correct" roast level—only the one that matches your palate.
Matching Roast to Your Machine
Your equipment influences ideal roast selection. Here are some guidelines:
- Automatic espresso machines: Medium to medium-dark roasts work best. These machines often can't match the extraction quality of commercial or prosumer equipment, and darker roasts compensate with bolder flavour.
- Semi-automatic espresso: Any roast level works if you dial in appropriately. Lighter roasts require finer grinding and sometimes higher temperatures.
- Pod machines: You're limited to what the manufacturer offers, but Nespresso and others now include lighter roast options alongside traditional dark pods.
- Drip coffee makers: Medium roasts are classic and reliable. Light roasts work well if your machine brews at proper temperatures (92-96°C).
- French press: Medium to dark roasts handle the long immersion without over-extracting. Very light roasts may taste underdeveloped.
Experimenting with Roast Levels
The best way to understand roast levels is to taste them side by side. Many specialty roasters offer sample packs with the same origin bean roasted to different levels, making the comparison direct and educational. Pay attention to how acidity, body, and flavour complexity change across the spectrum.
Don't feel pressured to conform to specialty coffee trends or traditional preferences. If you love the bold simplicity of dark roast, embrace it. If you discover the complex fruitiness of light roasts, explore that world. Coffee is ultimately about enjoyment, and the best roast is the one that makes you happiest when you take that first morning sip.