The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in Parashat Balak, discusses the concept of "Yayin Mebushal" – wine that has been boiled. Although Halacha forbids using wine that has been touched by a non-Jew, this prohibition does not apply to Yayin Mebushal. Once wine has been boiled, it can no longer become prohibited through contact with a non-Jew.
At one point does wine become considered "boiled" and thus attain the status of Yayin Mebushal?
The Ben Ish Hai writes that wine is considered "Mebushal" once it is brought to a boil and some wine has evaporated. Once evaporation begins to occur, the wine has the status of Yayin Mebushal and cannot become forbidden through contact with a non-Jew. Hacham Ovadia Yosef, in his Halichot Olam (Balak, 6), clarifies that the wine must be boiled at a temperature of 80 degrees Centigrade (176 degrees Fahrenheit).
Accordingly, Hacham Ovadia adds, wine that has undergone pasteurization is, strictly speaking, considered Yayin Mebushal and cannot become forbidden through contact with a non-Jew. Other authorities – including Rav Yosef Shalom Elyashiv (contemporary) and Rav Shlomo Zalman Auerbach (Jerusalem, 1910-1995), disagree with this ruling, and maintain that the process of pasteurization does not render wine Yayin Mabushal. Hacham Ovadia therefore concludes that one should preferably ensure that pasteurized wine does not come in contact with a non-Jew if it had not been boiled in addition to pasteurization. If, however, a non-Jew did touch pasteurized wine, it is permissible "Be’di’abad" (after the fact). Hacham Ovadia makes reference in this context to the principle of "Ha’Torah Hasa Al Mamonam Shel Yisrael," which means that the Torah is sensitive to people’s financial constraints, and does not want to cause them unnecessary financial losses. Therefore, since Halacha does, strictly speaking, consider pasteurized wine "Mebushal," we may permit drinking pasteurized wine that came in contact with a gentile, even if ideally this situation should be avoided.
The Ben Ish Hai notes that boiling wine can only prevent wine from becoming forbidden; it cannot reverse the status of forbidden wine. Meaning, if non-Mebushal wine comes in contact with a gentile and thus becomes forbidden, it remains forbidden even if it is then boiled. Boiling only has the effect of preventing it from becoming forbidden if a gentile touches it.
Furthermore, if Yayin Mebushal is mixed together with ordinary, non-Mebushal wine, and a non-Jew touches the mixture, then it becomes forbidden. Even though the Yayin Mebushal constitutes the majority of the mixture, the mixture nevertheless becomes forbidden through contact with a non-Jew. As long as there is even a drop of non-Mebushal wine in the mixture, it can become forbidden.
Summary: Wine that has been boiled does not become forbidden if it is touched by a non-Jew. Some authorities maintain that pasteurized wine falls into this category, but it is preferable not to rely on this view, and to ensure that pasteurized wine does not come in contact with a non-Jew. Nevertheless, if a non-Jew does touch pasteurized wine, it may be used. If boiled wine is mixed with even a small amount of ordinary wine, and a non-Jew touches the mixture, it is forbidden.
