QUESTION: What is the grind size I should use in an Aeropress machine? I’m having trouble getting my Aeropress to brew coffee the way I like it. — Jason D.
ANSWER: Aeropress recommends you grind coffee on the fine drip or espresso settings. This puts the appropriate grind size for an Aeropress somewhere between what you’d put in a French press (coarse) and the fine grind of an espresso. The texture of your coffee should be similar to the grain size of table salt. Aeropress explains that espresso grind will take longer to press, and you might have trouble using more than one scoop at a time. However, the espresso setting will give you a better tasting brew more quickly than the fine drip setting.
You can even use a pre-ground drip coffee in your Aeropress machine, but for best results, you may need to either brew for a longer time or use more coffee to get the best flavor in your brew. Of course, since coffee begins to lose its flavor as soon as it is ground, we recommend you grind your own beans to use in the Aeropress.
Extraction and Grind Size With Your Aeropress
How finely or coarsely you grind your coffee will determine its level of extraction, which in turn determines the taste. A finer grind will allow water to move through the grinds more slowly, so your brew time should increase. More coarse grinds will require water to move through the Aeropress more quickly, so your brew time will be reduced.
As you adjust the extraction of the coffee into the water by calibrating the brew time and grind setting, you’ll need to know what over-extraction and under-extraction taste like. Coffee that is over-extracted (brewed for too long or grind setting too fine) tastes too strong, bitter, or burned. Coffee that is under-extracted (not brewed long enough or grind setting too coarse) tastes weak and watery or even sour.
If your coffee tastes over-extracted, you should adjust by reducing the brew time and/or grinding your beans more coarsely). If your coffee tastes under-extracted, you should adjust by increasing the brew time and/or grinding your beans more finely.