What factors determine the grade classification in clove?

The specifications given by the Sri Lanka Slandered Institute is as follows:

- Cloves Handpicked

This clove grade is a minimum of 99% free from impurity, well-sorted manually with less than 10% headless, free from coco-cloves/white cloves, and almost no baby cloves.

- Cloves Grade 1

This grade is always to be allowed at least 1% of admixture, very few baby cloves, bright in color, and the percentage of headless is less than 25%.

- Cloves FAQ

This quality of cloves is of average quality with 3 to 4% admixture, tolerable, and slightly dark/bright. 

Source:

World Wide Commodity