If it has a pair (or more) of blades, it will cup up the coffee beans, and not offer a very coherent kind of grind. Some bits will be smaller, some will be larger. You have to keep twisting and shaking the coffee grinder, until all the bits a cup up. Unfortunately this often results in bits too fine, and bits too large.
How does the grind affect the amount of caffeine in coffee?
Why is a coarse coffee grind better?
This is because a coarse grind offers a more ‘complete’ flavor, as the steeping time is just right for that. Let me explain a bit about the surface area first. If you want to make the best coffee at home, you absolutely need to check my article on the best coffee gear.
How does grinding coffee beans affect the extraction?
Answer Wiki. In theory, grinding affects coffee beans in the same way as grinding any other substance: increasing surface area, which speeds up the extraction process.