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Coffee Mills: Density Sorting Coffee Beans

Molecular density sorting is one of the best ways to separate broken, small, undeveloped, and otherwise defective coffee beans.  There are usually 2-3 stages of density sorting.  In the first stage, the very dense rocks and stones are removed from the coffee. In the second stage, the coffee is hulled and the debris is removed.  The third stage is most important and uses a densimetric table to separate the coffee into three or more densities.  The settings on the machine must be continuously monitored to ensure that proper density sorting is occurring.  The light and less dense coffee beans move to the right bottom side of the table, whereas the dense high-quality coffee beans move to the upper third of the table.  This table will also remove any remaining debris that have made it through the previous density sorting stages. If the coffee mill is concerned with attaining the highest quality coffee possible, it may run the upper third coffee again to further separate any small deviations in density.

Videos of Density Sorting: medium (1.95 Mb) or small (472 Kb)

For more information about coffee quality control, defective coffee beans, and sorting coffee by density, read "Sorting out the Beans: Optimize Your Roast" or visit

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