Does the type of bean affect grind consistency?

When you change the type of coffee you are brewing, you are essentially changing the physical material your grinder has to process. A light-roast, high-altitude Ethiopian coffee is very dense and hard, meaning it requires more force to break down. If your grinder is not powerful enough, it may struggle to maintain a consistent speed, leading to an uneven grind. Conversely, a dark-roast coffee is porous and brittle, shattering easily under the burrs.

These physical differences mean that you cannot use the same grind setting for every coffee. A light roast might require a slightly finer setting to extract enough flavor, while a dark roast might need a coarser setting to avoid over-extraction. If you don't adjust your grinder when switching beans, you will likely find that your brew times and flavor profiles change unexpectedly. This is why 'dialing in' is a continuous process, not a one-time setup.

Bean density is also influenced by the processing method. Natural-process coffees, which are dried with the fruit intact, can have different structural characteristics than washed-process coffees. These differences can affect how the beans feed into the burrs. If you are using a single-dose grinder, you might notice that some beans 'popcorn' or jump around more than others, which can lead to inconsistent feeding and, consequently, an inconsistent grind.

In practice, the best approach is to treat every new bag of coffee as a new challenge. When you open a new bag, start with your baseline setting, but be prepared to adjust. If the coffee tastes thin or sour, try a finer grind. If it tastes bitter or harsh, try a coarser grind. By understanding that the bean itself is a variable in your brewing equation, you can better control the outcome and ensure that you are getting the best possible flavor from every origin.