Raisin manufacturing process There are four primary methods for producing raisins including the natural, dehydration, continuous tray, and dried-on-the-vine methods. The most popular of these is the natural method which will be explained in some detail. Raisin manufacturing process The basic steps in natural raisin manufacturing include harvesting, processing, and packaging. While a small portion of raisins are made by mechanically dehydrating grapes, the majority of them are produced by...