What difference does the roast make?

Roasting is a crucial stage in speciality coffee as this is where the green bean is transformed into the delicious beans that we know and love. This process is intrumental in producing the flavours and aromas of each coffee bean, as the level of roast affects the overall flavour. And with three different roast levels, including light, medium and dark, there are a whole host of flavours to discover.

Coffee roasters will decide the roast degree dependant on the natural characteristics of the green bean. If a coffee bean is naturally fruity or floral in flavour, for example, they’ll roast this particular coffee bean lightly to make sure the natural flavour profiles are enhanced. Coffee beans with naturally rich, chocolatey or caramel attributes, for instance, will be roasted for longer to produce a much darker roast that compliments the natural qualities of that coffee.

Firstly, it’s important to note that roast levels are completely dependent on personal preference and choice, so there really is no set answer when it comes to which roast is best. But there are many differences between each roast which affects the overall taste of the coffee bean, including acidity and bitterness, oils and gases, and more.

Lightly Roasted Coffee

Light roast coffees are very easy to distinguish from other roasts as they differentiate in appearance to medium and dark roast beans. Unsurprisingly, light roast beans are much lighter in colour than a darker roast, and are usually less oily in appearance. They’re roasted between eight to ten minutes, which is normally when the ‘first crack’ is heard. This crack is similar to the pop of popcorn, and demonstrates to a coffee roaster that the beans have reached a light roast. Once this crack happens, the beans will enter the drum to cool down as quickly as possible to stop cooking any longer and alter the flavour even further.

Lightly roasting speciality coffee produces a delicate flavour as the low temperatures in the roaster and quick roasting process allows for most of the original characteristics of the coffee to be retained, resulting in fruity, floral, nutty or sweet flavour notes being very prominent. This also affects the acidity, as the natural acids of the bean aren’t cooked during the roasting process, causing a very high acidity level. As flavours in a light roast are much more delicate than those of a darker roast, brewing these types of coffee beans requires lots of knowledge and skill. This is because light roasts lend themselves more to a drip brew filter coffee or any brewing method that uses low pressure, which naturally rules out espresso. 

Medium Roast

Unsurprisingly, medium roast coffees have a blend of characteristics from both light and dark roasts, which result in them producing much more balanced coffee beans compared to their counterparts. This is because they can be roasted beyond when the first ‘crack’ is heard, but not long enough for the second ‘crack’, allowing them to develop light-medium roasts or medium-dark roasts. This type of roasting produces flavour profiles that aren’t as delicate as a light roast, nor as rich as a dark roast, but instead is a great balance between the two. Bright and floral flavour notes are transformed by flavours picked up during the roasting process, resulting in those flavours becoming not as distinctive as they once were. But the beans pick up more developed notes from the roaster which adds to their flavour profile and helps to create a deeper flavour that isn’t too acidic, but has a much more balanced aroma, flavour and body.

Darker Roast

In terms of appearance, dark roast coffee is exactly what it says. It’s a dark brown colour and usually has an oily coating which is produced during the roasting process. This is due to the Maillard reaction, which is a series of chemical reactions that happen during the coffee roasting process, involving sugars and proteins. It’s very similar to caramelisation, which is why some dark roast coffees often has caramel undertones. For this reason, it’s one of the most influential aspects of roasting speciality coffee, as it determines the characteristics of a dark roast coffee. The result of the Maillard reaction leaves the beans dark in colour and very oily on the surface, as the longer the beans are roasted for, the more oils and gases are produced in the coffee beans.

When roasting a dark roast, the process usually lasts just before or just after the second 'crack', to get that perfectly deep and delicious flavour. Dark roasts produce very distinctive flavours, as roasting the coffee beans for longer creates much smokier and chocolatey flavour notes than a lighter roast. And the longer the coffee beans are roasted for, the more forgiving those beans become, as the process produces more consistency within the flavour, acidity and body of beans than that of a lighter roast. For any barista, this works to their advantage as the beans don’t require as much skill and knowledge to make a consistently great cup of coffee than a lighter roast. 

As a speciality coffee roaster, it’s important to analyse each coffee bean that we source through a cupping session to determine the degree of roast needed. Through our knowledge and skill, we’re able to allow the natural qualities of our beans to shine through by roasting them to perfection in our state-of-the-art roaster. And whilst we understand that people have different preferences on their preferred roast level, we know anyone will be able to find their favourite roast whilst exploring our variety of speciality coffees.

If you’d like to understand how we roast our coffee beans, you can watch our video here.