Next comes the vintage, a critical and difficult period because each variety should be harvested at its optimum maturity, based upon the sugar and acid ration. Upon nearing maturity, the grapes must be tested repeatedly until they reach the desired ratios. The deficiency of one or the other greatly affects the final wines.
Once harvested, the grapes are delivered to the winery either in grape picking boxes or in bulk, such as in steel gondola trailers, which hold anywhere from 1 to 5 tons of grapes. Upon delivery, a gondola is raised from one side by means of a mechanical hoist, thus causing the grapes to slide and role out onto a conveyor, which, in turn, carries the grapes to the crusher.
The grapes are then crushed by means of two rollers set close together or by the more poular crusher unit, which consists of revolving paddles which "slap" the berries free of the stems, cracking them open. Regardless of type, both crush the berries and remove the stems, which are automatically expelled at the far end of the crusher. The must (crushed grapes) are pumped from the bottom of the crusher into the fermenter.
Both red grapes and white grapes are treated alike at the crusher. However, once the must leaves the crusher and is in its respective tank, they receive quite different treatment.