Light, medium, dark: what roast level actually means

Roasting is controlled burning. Yes, really. You are applying heat to green coffee beans until they change colour, expand and develop flavour. The longer and hotter you roast, the darker the bean gets and the more the original coffee flavour gets replaced by roast flavour.

That is why a light roast Ethiopian tastes like blueberries and jasmine, while a dark roast Italian blend tastes like chocolate and smoke. Same plant, completely different cup.

What happens during roasting

Green coffee beans start out like little stones: hard, grassy and flavourless. Heat triggers a chemical reaction called the Maillard reaction, the same thing that browns bread and sears meat. Sugars caramelise, acids break down and hundreds of new flavour compounds form.

The first crack, around 196°C, is when the bean pops like popcorn and doubles in size. Most roasters pull the bean somewhere between first crack and just after second crack, depending on the style they want.

The three main roast levels

Light roasts stop shortly after first crack. The bean is still dense, the surface is matte and the cup is bright, acidic and complex. These are the roasts that show off origin character best.

Medium roasts go a bit further, developing more body and sweetness while keeping some origin character. This is where most espresso blends live, because it balances acidity with the richness milk drinks need.

Roast level is not a quality ranking. A great dark roast beats a bad light roast every time. It is about matching the roast to the coffee and the brew method.

Priya Nair, head barista

Which roast for which brew method

Espresso generally wants medium to medium-dark. The pressure and short extraction time need a roast that is soluble enough to give you body without choking on acidity. Our house blend sits right in that sweet spot.

Filter methods like pour-over and batch brew prefer light to medium roasts. The longer contact time extracts more, so you want a coffee with acidity and clarity rather than roast bitterness. French press can go either way but usually likes something in the middle.

Why we roast what we roast

Every coffee we buy gets tasted as green, then we decide the roast profile that makes it taste best. A delicate Gesha gets a very light touch. A heavy Brazil gets pushed darker to bring out its chocolate notes.

We do not force coffees into categories. If a coffee shines at a light roast, that is how we sell it. If it needs more development, we give it more. The bag tells you what roast it is and why we chose it.

Beyond the labels

Light, medium and dark are useful shorthand but they are not precise. Two 'medium' roasts can taste completely different depending on the bean, the roaster and the brew method. That is why we include tasting notes on every bag.

The best way to understand roast levels is to taste them side by side. Our Saturday cuppings are free and we often do roast-level comparisons. Or buy three bags of the same coffee at different roasts and do it at home.