Do beans from different origins need different grind sizes?

When you switch from a dense, high-grown Kenyan coffee to a softer, lower-altitude Brazilian bean, you are working with two physically different materials. Coffee bean density is primarily determined by the altitude at which the coffee was grown; the slower maturation process at higher elevations creates a harder, more compact cellular structure. This density directly impacts how the bean interacts with water during the brewing process.

Because dense beans are harder, they are more resistant to water penetration. If you use the exact same grind size for a very dense bean as you would for a softer one, you might find that the dense bean under-extracts, leading to a sour or thin cup. Conversely, a softer bean might extract too quickly, potentially becoming bitter or astringent if the grind is too fine. Adjusting your grind size is one of the most effective ways to compensate for these structural differences.

Beyond density, moisture content also plays a role. Beans that have been processed or stored differently will have varying levels of water activity, which affects how they shatter during grinding. A bean with higher moisture content might produce more 'fines'—the tiny, dust-like particles that can clog your filter and slow down draw-down time—compared to a drier, more brittle bean. This is why even within the same origin, you might find that a fresh crop requires a slightly different setting than an older, 'past-crop' bean.

In practice, treat your grind size as a dynamic variable rather than a fixed setting. When you open a new bag of coffee, start with your baseline setting, but be prepared to dial it in. If your brew is tasting weak or sour, try a slightly finer grind to increase surface area and extraction. If it tastes bitter or the brew time is dragging, coarsen your grind. By paying attention to the physical characteristics of the bean, you can unlock the full potential of every origin you brew.