Coffee bean grinders can be classified into two. The first type is the blade grinder. Devices that fall under this category make use of a small metal blade to finely cut up the coffee beans. These are cheap compared to burr grinders.However, they do come with a number of disadvantages. First, if you are particular about the quality of the grinding, you will be disappointed with the output of blade grinders. This is because most of the time, the resulting grounds are unequal. Also, the blade can heat up considerably, so if coffee grounds are left in a grinder for a time, they can acquire a bitter taste as a result of being burned.