Why is bean size sometimes irrelevant to quality?
Bean size is often a poor indicator of quality because it is primarily a physical characteristic influenced by variety, altitude, and processing, rather than flavor potential. While large beans are traditionally easier to roast evenly, smaller beans from high-altitude, slow-maturing varieties often possess superior density, complexity, and acidity, proving that size does not equate to a better cup.
In the early days of the coffee trade, screen size—the physical measurement of a bean's diameter—was used as a primary proxy for quality. The logic was simple: larger beans were thought to be more mature and therefore more flavorful. This led to the development of grading systems where 'Screen 17/18' beans commanded higher prices simply because they were physically larger. However, modern specialty coffee has largely moved past this outdated metric.
Quality in coffee is defined by the cup profile, which is determined by a complex interplay of genetics, terroir, and post-harvest processing. A bean's size is often dictated by the coffee variety; for example, the Maragogype variety is naturally massive, yet it does not necessarily taste better than a smaller, high-density Bourbon or Geisha bean. In fact, many of the world's most prized coffees come from high-altitude regions where the cooler temperatures cause the coffee cherries to mature slowly, resulting in smaller, denser beans that are packed with sugars and complex acids.
When we focus too heavily on bean size, we risk ignoring the actual sensory experience. A large bean that was grown at low altitude in poor soil will almost always be inferior to a smaller bean grown in ideal conditions. Furthermore, roasting technology has advanced to the point where roasters can easily manage beans of varying sizes, provided the batch is sorted for density and moisture content. The physical size of the bean is merely one data point, and it is often the least important one when compared to the 'cup score' or the specific flavor notes of the lot.
In practice, when you are buying coffee, look for information about the farm, the altitude, and the variety rather than the screen size. A smaller bean from a high-altitude farm is often a sign of a more concentrated, flavorful cup. By prioritizing these factors over physical dimensions, you are more likely to find coffee that truly excels in the cup, regardless of whether the beans are large or small.
- · https://sca.coffee/research/coffee-standards