It is prohibited to drink wine (or grape juice) which was handled by a non-Jew. This wine is known as stam yenam. However, non-Jews may touch and handle grapes, even if a bit of juice is extracted during contact.
At what point in the process of wine-making is the liquid squeezed from the grapes considered to be wine, and subject to the laws of stam yenam?
The Shulchan Arukh (Yoreh De’ah 123:17) explains that the liquid is considered to be wine, for these halakhot, when one presses the grapes with the intention of extracting the liquid, and the juice is separated from the pits, peels and sediments. This process, known as hamshacha, is performed on a board, positioned on an incline, which would allow the juice to trickle down while the solid matter stayed behind. At this point, one must be concerned with the prohibition of stam yenam.
This may be relevant for those who buy drinks at fruit/smoothie bars. Often, fruits and vegetables, such as apples, oranges, melons and berries, are blended together and made into shakes and "smoothies." At times, grapes are added to the mixture. In this case if a non-Jew puts the grapes into the blender, is the entire shake prohibited?
It appears that this case of making shakes and smoothies, when included, grapes are completely crushed, and the juice is not separated from the peels and pits, and therefore the liquid extracted from the grapes would not be considered wine, and not susceptible to the prohibition of stam yenam.
