Roasting is just controlled cooking, but the difference of a minute or two on the roaster can completely change how a coffee tastes. Green, unroasted coffee beans barely taste like coffee at all. It is heat that unlocks the aromas and flavors we associate with the drink, and how far you push that heat determines everything from color to acidity to body.
Two audible milestones mark the major transitions. "First crack" happens around 196 to 202 degrees Celsius, a loud popping sound similar to popcorn, as trapped steam and carbon dioxide force their way out of the bean. This is where light roasts stop. "Second crack" happens later, around 224 to 232 degrees Celsius, a quieter, more rapid cracking as the bean's structure breaks down further. Dark roasts are pushed past this point.
Light roasts are pulled right around first crack, typically finishing in the 196 to 205 degree Celsius range. They preserve more of the bean's original character, meaning the specific flavors of where that coffee was grown come through more clearly, along with higher acidity. If you want to taste the actual origin of a coffee rather than the roast itself, light is usually the way to go.
Medium roasts push a bit further, finishing around 210 to 219 degrees Celsius, past first crack but well before second. This is the range most people default to because it balances the origin's natural character with some of the sweeter, more rounded flavors that development brings. It is a safe, crowd-pleasing middle ground.
Roasters often use more specific names within these three broad bands, terms like "City roast," "Full City," "Vienna," or "French roast" show up on bags and menus and can be confusing if you have only heard "light, medium, dark." Full City generally sits right at the edge of second crack, a touch darker than a standard medium. French roast and Italian roast sit deep into dark roast territory, well past second crack, aimed at cutting through milk in espresso drinks. These names are not perfectly standardized between roasters, so treat them as a rough guide rather than an exact science. Plain Sight Coffee Roasters publishes its own notes on Philippine-grown beans, which is a useful local reference for how these terms get applied in practice here.
Dark roasts go past second crack, finishing anywhere from 225 to 245 degrees Celsius. By this point, a lot of the bean's original origin character has been replaced by the flavor of the roasting process itself, bittersweet, sometimes smoky, with a heavier, oilier body and noticeably lower acidity. This is the profile a lot of traditional espresso blends are built around.
None of these are objectively correct. A dark roast is not "burnt coffee done wrong," and a light roast is not automatically "better coffee." They are different tools for different preferences. If you tend to find coffee too sour or too thin, you will probably lean dark. If you find most coffee tastes the same and a little flat, a light roast from a shop that actually discloses its origin might be the wake-up call you are looking for.
Roast level also nudges you toward certain brewing methods more naturally than others, even though none of the pairings are strict rules. Light roasts, with their higher acidity and more delicate flavors, tend to shine in pour-over and drip methods that let those subtler notes come through clearly. Dark roasts, bolder and less nuanced to begin with, hold up well to the pressure and concentration of espresso or the fuller body of a French press, methods that would otherwise mute a light roast's more delicate character. If you already know which brewing method you prefer, that is a reasonable starting point for choosing a roast level too.
One common myth worth clearing up, dark roast is not automatically higher in caffeine, and if anything the opposite is closer to true by weight. Longer roasting burns off a small amount of mass and makes beans less dense, so if you measure coffee by volume, say a standard scoop, a dark roast scoop will actually contain slightly fewer beans by weight than a light roast scoop of the same volume, and therefore slightly less caffeine. If you measure your coffee by weight instead of volume, which is the more accurate approach anyway, the difference largely disappears. Either way, roast level is a poor way to guess at caffeine strength, bean type and brew method matter far more.
It is also worth knowing that roast level affects how long beans stay fresh, not just how they taste. Darker roasts are more porous and oilier, which means they lose their aromatic compounds and can turn stale slightly faster than a light roast of the same age, even when both are stored identically. This is a small factor compared to overall storage practice, covered in our storage guide, but worth knowing if you are trying to figure out why one bag seems to fade faster than another.
Decaffeination, worth a brief mention here since it is often confused with roast level, happens before roasting entirely, using water, solvent, or carbon dioxide-based methods to remove most of the caffeine from green beans. A decaf coffee can be roasted light, medium, or dark just like any other bean, roast level and caffeine content are genuinely separate decisions, even though people sometimes assume decaf is automatically a dark roast.
The best way to learn your own preference is to taste roasts side by side rather than guess from a bag description. Franken Coffee Bar + Roastery roasts its own beans in San Roque, which makes it one of the more useful local spots to actually ask what roast level you are drinking and compare it against something else on the menu. If you would rather watch someone taste roasts side by side than read about it, Home Barista Corner does exactly that kind of comparison on camera. For the step before roasting, how the cherry itself is processed, read our processing guide, or head back to Coffee 101 for the full picture. To see roast level applied to one local bean, read our guide to Sagada dark roast versus medium roast.