Why do I need a different grind for Aeropress?

The AeroPress is unique because it doesn't fit neatly into the categories of 'drip' or 'espresso.' It uses immersion—where the coffee sits in water—and then applies manual air pressure to push the liquid through a paper filter. Because of this, your grind size needs to be calibrated to the specific contact time and pressure you plan to use.

If your grind is too coarse, the water will pass through the coffee too quickly during the press, leading to an under-extracted, sour, or thin cup. If your grind is too fine, you will encounter significant resistance when pressing, which can lead to over-extraction and bitterness, or even cause the coffee to bypass the filter entirely. The goal is to find a 'medium-fine' setting that provides enough resistance to create a rich, full-bodied cup without making the physical act of pressing a struggle.

Because the AeroPress is so flexible, your grind size should also change based on your recipe. If you are using a shorter brew time, you will need a finer grind to compensate for the reduced contact time. If you are using a longer steep time, you should move toward a coarser grind to prevent over-extraction. This is the beauty of the device: it allows you to experiment with different variables to find the flavor profile that suits your taste.

In practice, start with a grind similar to table salt. If the press feels too easy and the coffee tastes sour, move your grind finer. If the press feels difficult and the coffee tastes bitter, move your grind coarser. By adjusting your grind size in small increments, you can master the AeroPress and unlock a wide range of flavors from your favorite beans, from bright, fruity notes to deep, chocolatey undertones.