1.- What is the way that today they make “yayin mevushal”?
2.- Is there many poskim that say that today’s “yayin mevushal (mefustar)”its not mevushal, and its can be “yayin nesech”?
Wine is made mevushal by actually boiling it.
Rav Shmuel Wosner maintains that pasteurizing does not render the wine mevushal, because it doesn’t adversely affect the wine. See Mibeis Levi Vol. 14, p. 55, and Shevet Halevi Vol. 2, no. 51. This is also the opinion of Rav Shlomo Zalman Auerbach (Minchas Shlomo 1:25), and yibadel lechayim tovim Rav Elyashiv (see Shevus Yitzchak, Pesach, siman 16).
