One of the most frequent coffee questions I get asked is “What is the difference between light, medium and dark roasts?" People are curious to know what the different roast descriptions mean? Why is it important? How does it affect flavour? Is one better than the other? How do you pick the right roast?
Well, here are a few high-level tidbits to help de-mystify roast types.
So, the roasting process is a careful science that changes the beans' flavour profiles. The longer the beans roast, the more acidity levels drop, and bitterness increases through caramelisation. The roaster will balance this process to find the optimal point when the fruit’s body and sweetness peak and then starts to plateau. Roast the beans for too little time or at a sub-optimal temperature and the flavour will be too fruity, too bright and will lack depth and versatility. Roast for too long, however, and the beans will become overly smokey, too astringent and, well, pretty undrinkable.
The origin of the bean, the soil they’ve grown from, and the drying and hulling process all contribute to the beans’ specific flavour profile - and this, in partnership with the roaster’s nose, palette and roasting times are what determines whether you love or hate their roast. And that’s the beauty of it, like wine - there really aren’t any rules. You either really enjoy the flavour and experience of the coffee, or you don’t… the fun part is trying different roasts and figuring out what your flavour profile and preferences are. This is where the art of coffee and skill of the roaster really comes into play;
"Roaster palette definitely influences the beans and flavours you produce, at least when you are a smaller more specialised roaster. Having grown up in NZ I love the darker and chocolatey flavours that I get from Guatemala and Mexican beans, without needing to roast them to a darker level - the medium roast produces these characteristics. This is the Art of coffee roasting!" - Damian Hamilton, Pirate Coffee
Although coffee enjoyment and taste really is mostly a subjective practice, there are some simple guides you can use to help make some decisions about which roast types may be best for you. For example, do you prefer bright, fruity, acidic flavours (light), or more bold, smokey, caramel notes? (dark) What is your preferred brew method? Do you use a french press / plunger? (Perfect for light/medium roast) Or do you have a moka pot or espresso machine? (Best for darker roasts).
One thing to note is caffeine levels actually decrease the longer the bean has roasted. So whilst a light coffee is generally more floral and acidic in taste, it will pack a punch on the caffeine front. The darker and glossier the roasted bean, the less caffeine will be present.
Want to expand your coffee-tasting lexicon? Check out this flavour wheel for the full gamete!
Feature image by Andrew Neel
Roasted bean images: