Coffee beans come in all shapes and sizes but do you know how that can affect your cup of coffee?
The size of a bean is down to a number of factors including plant variety, growing altitude and other growing conditions like temperature and soil type.
Many coffee producing countries sort their beans by size, known as grading. The terminology varies between countries, for example in Colombia the largest beans are graded as Supremo whereas in many African countries such as Kenya they would be classed as AA. Sorting the different sizes into separate batches can help to ensure consistency through out that particular lot.
It is often accepted that larger beans are a better quality, as they will have had more time developing and ripening on the plant. This isn't always the case as some of the smallest beans, known as peaberries, are often very high quality with plenty of sweetness and flavour.
It is useful to have beans with uniformity of size within a lot to help ensure consistency when roasting. Quite simply, larger beans will roast at a different rate to the smaller ones so mixed sizes can lead to inconsistent flavour.
In some cases (for instance, with our house roast) this inconsistency in size can work to the benefit of the coffee. Our wood roaster creates a complex but well-balanced flavour profile in our house coffee despite the varying size of the beans from the three origins that make up the blend.
When purchasing coffee to sell, roasters will often look at the size of a coffee as a marker of quality. We say, the best way to judge is to taste it!