793. Extracting Juice
Shabbos 21:12
One who extracts from produce is liable for threshing. This includes squeezing olives and grapes. One may therefore not squeeze berries or pomegranates because some people squeeze them for juice in the manner of olives and grapes. This is a preventive measure out of concern that one may come to squeeze olives and grapes. It is permitted to squeeze other types of fruit, like quince and apples, since people do not normally squeeze them.
Shabbos 21:13
One may squeeze pickled or cooked foods in order to soften them. If one’s intention is to extract liquid from them, it is prohibited. One may not crush snow in order to cause liquid to flow from it but one may crush it into a bowl or a cup. If garlic, unripe grapes or unripe grain were crushed before Shabbos, then one may crush them further on Shabbos if necessary, and they may be ground by hand on Shabbos if further grinding is necessary. Therefore, one may continue grinding kernels of grain with a wooden spoon in a pot on Shabbos after removing the pot from the fire.