Mevushal grape juice

Hi,

[Due to a rabbinic prohibition intended to encourage intramarriage by limiting Jews' ability to socialize with non-Jews, wine which is handled by people who are not Jewish is not kosher. However, due to reasons beyond the scope of this email, wine which has been boiled does not lose its kosher status; this wine is called "yayin mevushal".]

The rules of wine apply to grape juice, despite its lack of alcohol. Therefore, grape juice becomes non-kosher if handled by non-Jews. However, grape juice is often produced by boiling the grapes before juicing them; in such a case, the grape juice is considered "mevushal".

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 1:50)

Have a great day,
Mordechai