What is density sorting in green coffee?

Density sorting separates beans by weight-to-volume ratio using a mechanical vibrating table. Dense beans - typically better developed, more uniform, and higher quality - migrate to one side; lighter, less dense ones (often defective, underdeveloped, or quaker-prone) drift to the other.

The physics is simple: air blows up through a vibrating inclined surface, causing beans to stratify by density. Operators designate cut-off points to separate the lot into density grades.

Density correlates with quality because high-density beans are usually the product of slow maturation at altitude - the bean developing fully before harvest. They also roast more predictably: a consistent-density lot heats more evenly in the drum, with fewer light beans racing ahead of the rest. If you're speccing green coffee for roasting consistency, density sorting is one of the variables worth asking about when comparing otherwise similar lots.