How are coffee beans graded?

Below are the grades under the SCAA Green Coffee Classification:

• Grade 1: Specialty Grade Coffee Beans - no primary defects, 0-3 full defects, sorted with a maximum of 5% above and 5% below specified screen size or range of screen size, and exhibiting a distinct attribute in one or more of the following areas: taste, acidity, body, or aroma. Also must be free of cup faults and taints. Zero quakers allowed. Moisture content between 9-13%.
• Grade 2: Premium Grade Coffee Beans - Same as Grade 1 except a maximum of 3 quakers. 0-8 full defects.
• Grade 3: Exchange Grade Coffee Beans - 50% above screen 15 and less than 5% below screen 15. Max of 5 quakers. Must be free from faults. 9-23 full defects.
• Grade 4: Standard Grade Coffee Beans - 24-86 full defects
• Grade 5: Off-Grade Coffee Beans - More than 86 full defects