Do you prefer it light, dark or somewhere in between? Here's a guide to coffee roasts from light to dark.
How much the coffee beans are roasted is an important factor to determine the taste of the coffee you get in the cup. Before roasting, green coffee beans are soft, with a fresh “grassy” like smell with very little or no taste. The coffee roasting process transforms these raw beans into the distinctively aromatic, flavourful, crunchy beans that we fondly refer to as coffee.
Before we go into coffee roasting it is important to acknowledge that there are other factors that enter into the complex equation that determine your coffee’s taste. Two coffee varieties, from different countries of origin or grown in different environments, will most likely taste quite different even when roasted to the same level, this is distinct especially at light to medium roast levels.
Besides this there are other factors like the age of the coffee, the processing method, the grind, and the brewing method that also affects the taste. A baseline, a rough guide to the taste you can expect, is the roasting level.
The most common & widely used way to describe coffee roast levels is by the colour of the roasted beans, ranging from light to dark. As beans absorb heat in the roasting process, their colour becomes darker. Oil appears on the surface of the beans at higher temperatures. Colour is not very accurate way of judging a roast, as beans vary. However, combined with the typical roasting temperature that yields a particular shade of brown, colour is a convenient way to categorise roasting levels.
Light roasts as it's name suggests are light brown in colour, with a light body. It does not have oil on the surface of the beans. Light roasts have a toasted grain taste and pronounced acidity. The origin flavours of the bean are retained to a greater extent than in darker roasted coffees. Light roasts also retain most of the caffeine from the coffee bean.
Light roasted beans generally reach an internal temperature of 180°C – 205°C. At or around 205°C, the beans pop or crack and expand in size. This is known as the “first crack”. So a light roast generally means a coffee that has not been roasted beyond the first crack.
Medium roasted coffees are medium brown in colour with more body. Like the lighter roasts, they have no oil on the bean surfaces. Medium roasts lacks the grainy taste of the light roasts, exhibiting more balanced flavour, aroma, and acidity. Caffeine is somewhat decreased.
Medium roasts reach internal temperatures between 210°C and 220°C — between the end of the first crack and just before the beginning of the second crack.
Medium-dark roasts have a richer, darker colour with some oil beginning to show on the surface of the beans. A medium-dark roast has a heavy body in comparison with the lighter or medium roasts.
The beans are roasted to the beginning or middle of the second crack — about 225°C or 230°C. The flavours and aromas of the roasting process become noticeable, and the taste of the coffee may be somewhat spicy.
Dark roasted coffees are dark brown in colour, or sometimes almost black. They have a sheen of oil on the surface, which is usually evident in the cup when the coffee is brewed. The coffee will generally have a bitter and smoky or even burnt taste. The amount of caffeine is substantially decreased.
To reach the level of a dark roast, coffee beans are roasted to an internal temperature of 240°C — about the end of the second crack — or beyond. They are seldom roasted to a temperature exceeding 250°C, at which point the body of the beans is thin and the taste is characterised by flavours of tar and charcoal.
So that's basically it — a guide to the common coffee roasts from light to dark. In addition to the colour
As coffee roasts get darker, they lose the origin flavours and take on more flavour from the roasting process.
The body of the coffee gets heavier, until the second crack, where the body again thins.
Lighter roasts have more acidity than darker roasts.
Light roasted beans are dry, while darker roasts develop oil on the bean surface.
The caffeine level decreases as the roast gets darker.
Ultimately, it’s all about the taste, the flavour, the aroma. You may prefer a lighter roast at a different time of the day, say in the morning due to the higher caffeine content and a darker one later in the day. Coffee, including the optimal roast level, is a very individual preference. What’s yours? Take your pick!