One of the reasons a burr grinder is a better tool for coffee drinkers than a blade grinder is that burrs provide a consistency and uniformity of grind that you just can’t get from whirring blades. There’s no denying how easy and repeatable it is to grind with burrs thanks to that uniformity.
Even though a grind might look consistent to the human eye, there’s actually still some variation in the size of coffee grounds if you’re able to look closely enough. With the right tools, you can see that even the best grinders like the Virtuoso+ produce a small amount of very small coffee grounds called “fines.”
Why does this tiny variation occur? It’s because of the nature of roasted coffee, and the way that burr grinders operate. Realistically speaking, it’s unavoidable to have these fines in a grind – but it might not actually be a bad thing after all.
Why do I Have Fines?
Roasted coffee is different levels of brittle. This is a good thing, because a brittle bean is easier to grind than a resilient, unroasted bean. To compare brittleness, picture two slices of bread toasted at different levels – lightly browned and slightly burnt. Break each in half and you’ll see that one of the toasts produces a lot more crumbs than the other and in different sizes. The same concept may apply to your favorite coffee beans. A burr grinder breaks a bean down into smaller pieces, and each time this happens we see fines produced. And yet, just like the complexity in bread and the almost infinite variations of circumstances that may affect our example, your coffee may be affected too.
Burr grinders control grind size not by the amount of time spent grinding – as it is the case with a blade grinder – but by the distance between the two burrs which do the grinding. Thanks to this design, most of the coffee ground this way will come out at the same size. Once a bean is ground to the desired size, it is released through the burrs and into the bin. That being said, a small percentage of coffee might shatter into a smaller piece than the size of the gap between the burrs. Fines, being very small particles of coffee, fall into this category.
What does this mean for me?
At any grind size, you can expect to have at least some fines present. While uniformity is important in coffee grinding, it’s important to remember that perfect uniformity is actually not entirely desirable! If you were to take a sift, for example, and remove everything under a certain size from a grind sample, you’d find that the resulting brew tastes flat and uninteresting. This is because of the way extraction works – basically those fines will extract more and create a more dynamic range of flavors in a given cup.
Of course, with too many fines a brew can taste over-extracted (which is generally not favorable). That’s why it’s still important to keep fines to a minimum, relatively speaking. Your burr grinder is a great tool to accomplish that!
Now, if you notice a few fines in your grind, remember that it’s totally normal and not necessarily a bad thing. Some fines can even help a shot or brew taste much more balanced than it would otherwise. If you’re worried, be sure to taste your coffee first and foremost – tasting is the most effective way to evaluate quality.
Chances are, you’ll like what you taste!