When reading about speciality coffee, you will often read that beans are graded. But what does this all mean? And who decided on the rules?
The SCA Coffee Beans Classification is a standardised method to compare coffee beans. It judges the relationship between the amount of defective coffee beans and the overall cup quality.
Coffee is graded by sorting the hulled green beans over screens with different sized holes. The beans remaining in each screen are then weighed, and the percentage of the total is recorded. Following this the coffee is roasted and cupped in order to evaluate the characteristics.
The coffee screening method was developed from a theory that coffees grown at high altitudes are more dense and larger, while also generally holding the best flavour profile. From this it can be deducted that there is a correlation between bean size, density and quality. While there are of course exceptions to this theory, the main objective is to produce beans of uniform size, so that an even roast can be achieved.
Grade 1: Speciality Grade Coffee Beans.
This is the highest grade of beans, and to be classified as Grade 1 Coffee, the beans need to have no primary defects and 0-3 full defects, with a maximum of 5% above and below the specified screen size. When cupping, these beans need to have a distinct attribute in one of the ares of taste, acidity, body or aroma, and be free of cup faults and taints. These beans also need to have zero of what is referred to as “Quakers” which are unripe or poorly roasted beans.
Grade 2: Premium Grade Coffee Beans
The second highest grade, and the one you most often would be drinking, these beans are the same as Grade 1 coffee beans, but are allowed a maximum of 3 Quakers and 0-8 defects.
Grade 3: Exchange Grade Coffee Beans
These beans will have 50% above screen 15 and 5% below it, with a maximum of 5 quakers, free from faults, but between 9-23 full defects are permissible. Supermarket brands are using these beans.
Grade 4: Standard Grade Coffee Beans
These will have 24 to 86 full defects per 300g. These are getting into dodgy territory.
Grade 5: Off Grade Coffee Beans
You really don’t want these beans, they have more than 86 full defects per 300g.