Grape crushers are devices commonly used in winemaking today. The type of appliance and especially its calibration will have a significant impact on the quality of the must and wine that we will obtain.
As its name indicates, grape crushers have the simple mission of squeezing, that is, of squeezing and "exploding" the grapes to facilitate the extraction of the juice. And they must do so without altering or breaking the grape seed and without exerting excessive pressure on the ollejo. Most of the small (non-industrial) models consist of two cylinders with longitudinal grooves that rotate in parallel and between which we make the grapes pass by gravity. As it passes between the rollers, the grape is squeezed and breaks, releasing its pulp. The type and spacing of the rollers (which is adjustable) will have a noticeable influence on the final taste of our wine. Each producer or winery makes the crushing in the way they consider most appropriate for the type of grape and the type of wine they want to make.
It should be used with the clean grape, since elements that are on the skin are already mixed with the grape juice, among them, the yeasts that live naturally on the surface of the oliejo. The result is a pulp of grape pulp with its seed and seeds that will pass to the next step of winemaking, in some cases a pressing, in others a previous fermentation. It is possible to obtain must by directly pressing the whole grape, but if it has previously passed through a juice extractor, the pressing process becomes much easier and, above all, much higher yields are obtained.
For small productions (tens or a few hundred kilograms of grapes), manual crushers are often used. They have a side disc with a handle that we will turn with the hand to move the cylinders that crush the grapes. For larger productions, crushers with an electric motor are usually used, but they are obviously much more expensive. The simple juice extractors require the grape to be introduced already destemmed (without the stems) but there are many other models that can crush and de-stem at the same time.
We ended up saying that the juice extractors do not have to be used exclusively with grapes and that the many models allow to squeeze other fruits of pulp (and without bone) like pears, apples. To facilitate the crushing of these fruits, the juice extractor allows you to attach a blade that will split the fruit into medium pieces that can then pass through the rollers. The obtained pulp is then pressed to obtain excellent juice yields.