Coffee snobs insist on an electric or manual burr grinder, to achieve the better-than-excellent perfection leading to a perfect cup. That doesn't mean you can't pulverize coffee beans in a blade grinder, or its even coarser cousin, the food processor. You're most likely to be satisfied with the results and the ease of cleanup with a mini-processor rather than a full-size appliance, unless you have a large volume of beans to grind. Warning: Check your processor's instruction manual before starting, as some are not designed to grind coffee.
Matching Your Brewing Method
It's best if you are going to use a food processor to grind the beans for a French press. The results are going to be coarse compared to a proper coffee grinder. This fact works to your advantage, as the French press works best with coarse grinds.
Amount and Timing
Measure 2 tablespoons of beans into the processor's work bowl for every 6 to 8-ounce cups of coffee you plan to make. Grind the beans just before brewing, so they are as fresh as possible.
Look for "Pulse" and "Chop" buttons on your food processor, or the roughly equivalent "Low" and "High" speed buttons. Pulse or press the "Low" button on the food processor five times, for 2 seconds each time.
Rock the processor gently so that the particles at the top of the bowl fall down near the blades, or tap the feet of the appliance gently on your work surface. Press the chop or "High" button for 30 to 45 seconds, keeping a close eye on the texture of the beans in the bowl by peering through its sides. When they look like large granules about 1/8 inch across, with some finer particles, but not quite powdery, you are done. Avoid additional pulsing that would lead to a fine powder.
Removing the Ground Coffee
Tap the processor cover to dislodge some of the flyaway grounds. Lift off the cover and set it aside. Twist and lift the work bowl off the motor base. Shake the bulk of the ground beans out of the work bowl and into your French press carafe. With a pastry brush, or even a designated 1-inch paintbrush, sweep out the remaining grounds from the food processor lid and bowl. Wash the food processor and store for the next morning.