Q. Would it be OK to drink wine a friend is making from grapes imported from Italy?
A. The fact that the grapes are imported from Italy is not an issue in the kashruth of wine. The kashruth laws involving wine are concerned more with who handles the wine than of what they use to make it. To be considered kosher, a Sabbath-observant Jew has to be involved in the entire wine making process. From the moment that the dry grapes are brought to the winery, or from when they are placed at home in a vat or container to be pressed or crushed, we have to be vigilant to prevent an inadvertent irreparable Hamshacha, that would disqualify the total wine making process. Hamshacah is defined in Halacha as the separation of the juice of the grape from the grape skin. Whether the wine is produced commercially or at home, any movement of the grape juice during its production (sampling, pouring, touching, pumping) qualifies for Hamshacha. If this Hamshacha is done by a non Sabbath- observant Jew or a Gentile anywhere along the process or after it has been bottled and not yet sealed properly, it will render it non-kosher
Rabbi A. Bartfeld - Revised by Horav Shlomo Miller Shlit”a.