Abstract

Xinyi Zhang

Hand-picked or machine-harvested grapes are usually tipped right into a receival bin whilst they arrive on the winery and conveyed by means of a screw mechanism to the grapeprocessing equipment. On arrival at the winery there is mostly a mixture of character berries, complete bunches (mainly with hand-picked grapes), stems, and leaves. The presence of stems for the duration of fermentation can result in a bitter taste in the wine, and the motive of destemming is to separate grapes from the stems and leaves. Mechanical de-stemmers commonly encompass a rotating cage perforated with grape-sized holes. Within this cage is a concentric axle with fingers radiating in the direction of the internal surface of the cage. Grapes skip thru the holes within the cage, whilst stems and leaves are expelled via the open end of the cage.