If you regularly buy coffee beans, you will have seen that there are various levels of roast available. From light Cinnamon and Half-City roasts to medium Full-City and dark Italian or Vienna, roasting is an incredibly important part of the farm to cup process.
Coffee beans start out green, and are usually stored and transported in this form to keep them fresh before roasting.
Roasting coffee beans doesn’t only give them the brown colouring which we see on the supermarket shelves. The overall aim is to release each bean’s distinctive flavour. To be slightly more technical, it changes the chemical and physical properties of the bean, releasing sugars.
A green bean has the same amount of caffeine and acids as a brown one, but it is the roasting process which makes the taste.
You may have heard that grinding your beans at home just before using them means a fresher taste because once the beans are ground the freshness immediately starts to be lost. Well, roasting them at home increases this freshness even further.
A lot of independent coffee shops are starting to roast on-site, especially when they are using single-origin blends where the flavour is incredibly important, and freshness is key.
If you fancy yourself as a bit of a budding coffee expert, then grinding at home may not be enough for you. Roasting is a bit of a craft and will improve your drinking experience by a mile.
You will need to buy green, unroasted beans that fit the flavour you’re after and are also suitable for the roasting level you like.
You’ll also need a roasting device. This can either be a small mesh tool which you pop over a flame or a hob and roast them manually, a large drum which you put over a flame and either turn manually or with electricity, or a machine which will do the roasting and turning for you.
Some people also use woks or popcorn makers, which aren’t dedicated to the job but can be just as good if you get the technique right.
No matter your machine or device, the process is very similar:
Once cooled, store your beans in an airtight container to keep them fresh, but try to let them vent and release any remaining carbon dioxide before doing this.
Keep them cool and dry, and they should last for about six weeks this way. Green beans should be stored in the same way, but these can be kept for up to six months in their pure form.
The optimum time to use and brew roasted beans differs. Filter coffee will be best if the beans are used the next morning, but espresso tasted better if the beans are left to de-gas further for a few days.