Coffee Grading factors
There is no universally used method for grading and classifying green coffee beans. But many countries have adopted protocols specified by the Specialty Coffee Association of America Green Arabic Coffee Classification System (SCAA GACCS) for grading coffee.
The International Coffee Organization claims there are many different aspects in classifying a coffee bean, and here are a few of them:
- Botanical variety
- Preparation method: (wet or dry)
- Bean (screen) size
- Number of defects
- Permissible defects
- Bean density
- Cup quality
Before export, green coffee beans are classified by the number of defects, cup quality, and size of the bean.
Size is important and helps determine the grade due to the simple fact that the bigger the bean, the better the quality.
Although other factors such as elevation, varietal, and definitely the number of defects also influence quality.
Common defects include: malformed beans, sticks and insect damage, to name a few.
Coffee grading screens
Beans are graded by size and sifted through screens before export. These screens are basically sheets with specific sized holes for the beans to fit through.
The grade is determined by an indicator hole that’s expressed in 1/64 of an inch. So beans given a grade 18 will pass through screen 18 (18/64 inch diameter holes), but won’t pass through screen 16/17.
Different grade terms differ globally
As mentioned, each country uses its own terminology to grade their coffee. So it might be useful to take a look at the following table to see how they differ, as it can get pretty confusing.
|Screen size||Inches||Industry classification||Central & South America||Colombia||Africa & Indian|
Only Africa and India use the term ‘elephant’ and even though the beans are very large, bigger is not better in this case as these coffee beans tend to break up during processing and roasting.
Why do we need coffee grading?
Generally green coffee is graded and classified for the export industry with the sole purpose of obtaining the highest price possible by producing the best quality cup.
More information can be found at: www.ico.org
Coffee bean grading chart source: www.driftaway.coffee/coffee-grades/