How do you brew coffee beans that you buy at home? Do I need to grind it?

When many friends drink coffee beans in a cafe, they will find that the barista grinds the coffee beans into powder and then cooks them. In fact, this is to increase the extraction area of coffee beans, a coffee bean has not been ground into powder, the extraction area is about 2 square centimeters, but after grinding, the surface area of coffee particles will increase. On a theoretical level, if a coffee bean is fully ground and unfolded, its area will be the size of a standard basketball court. A coffee bean begins the extraction process as long as it comes into contact with water, but in terms of extraction efficiency, a standard basketball court-sized coffee particle is extracted at the same time, which is much more efficient than an unground coffee bean. So on a theoretical level, coffee beans don't need to be ground to extract, but we grind them into powder in order to have a quick sip of coffee.

For Ethiopian coe22 beans that used to be street coffee, it takes only two minutes for 15 grams of ground beans to make a good cup of coffee, but 15 grams of unground beans may take an hour.