Unlike in traditional raisin-making, mechanically harvested raisins dry on the vine, not on the ground. Fruit-bearing vines are woven through a wire trellis on the side of the plant's trunk. Younger growing canes are positioned in an opposite direction. As grapes reach maturity, fruit-bearing canes are mechanically sliced with long blades, or can be severed by hand. Once cut, grapes dangle on the trellis as they are baked by the sun into raisins in about six to eight weeks.
Picking is done by a mechanical harvester, similar to one used in wine grapes.
Rumbling down the vineyard row, the harvester rakes the raisins off the plant, collecting them into a bin. Selma raisin grower Don Nielsen, no relation to Herman, says he has been harvesting mechanically since 1997 and has no plans to go back. I am not beholden to anybody.