Tasting Non-Kosher Wine

Question:I will be touring France, and our group will be doing wine tasting with wine that has no hashgacha. It is permitted to taste the wine if I spit it out thereafter?

Answer:We must deal with a few issues.
Some of the main kashrut concerns in Israel, Land-based mitzvot (e.g., teruma and ma’aser, Shemitta, orla) are of little concern outside of Israel, but stam yeinam is a major remaining issue. Stam yeinam is wine that was handled by non-Jews from the time the grapes are squeezed, and even after it is produced (until it has been mevushal (literally cooked) – the parameters are beyond our scope). Unsupervised wine made by non-Jews is therefore certainly forbidden as stam yeinam, a rabbinic prohibition of a complex nature, which we will briefly highlight.
One part of the prohibition of stam yeinam is that it is forbidden to drink the wine, out of concern that such behavior could lead (down the line) to intermarriage (Avoda Zara 36b). (This concern finds expression in similar prohibitions, e.g., bishul akum). If the wine was actually involved in idol worship, it could become yayin nesech, which is forbidden on the level of Torah law even in benefit other than drinking. Because these two prohibitions can be confused with each other, the Rabbis added a rabbinic prohibition on benefit from stam yeinam (Avoda Zara 29b; see Beit Yosef, Yoreh Deah 123).
There are sources that show leniency regarding the rabbinic prohibition on benefit from stam yeinam. The Shulchan Aruch (YD 124:7) rules that the wine of a non-Jew who is not involved in idol worship is forbidden only to drink, not in benefit, but it is not clear what category members of various religions fall under. The Rama (YD 123:1) says that since it is not common for non-Jews to use wine for libations, not all agree that there is a prohibition in benefit and that one can receive benefit if needed to avoid a loss of money (e.g., when it is the main available asset of a non-Jewish debtor). Wine tasting, even if one spits the wine out, is benefit due to the taste, and therefore it is forbidden if there is no loss. Not taking part in wine tasting is not a loss of money, and the loss of a pleasant opportunity does not count in this context. (Even being precluded from doing commerce in non-kosher wine is just a lost opportunity and forbidden- ibid.).
If stam yeinam were only forbidden to be drunk, we would have to check the status of putting food in the mouth and spitting it out. [For those who are unaware, it is cultured to spit out wine into a spittoon at wine-tasting events, allowing one to sample many wines and drive home.] According to the great majority of sources, it is forbidden to taste foods one is forbidden to eat (see Pitchei Teshuva, YD 98:1). One of the main sources for this concept is the gemara’s halachic advice for someone who is unsure if a mixture of kosher and non-kosher foods is permissible (discernable taste of the non-kosher minority element makes it forbidden). The gemara (Chulin 97a) says that one should give it to a non-Jew to taste, implying that a Jew may not taste it even if he plans to spit it out. On the other hand, Rishonim (see Beit Yosef, YD 42) allow a Jew to taste a piece of liver to see if the animal had a hidden gallbladder (important for the laws of tereifot), even though if they discover it is missing, the meat is forbidden.
Several possible distinctions are raised: 1. Tasting without swallowing is permitted when it is not clear that there is forbidden food, but one needs to swallow to rule out the presence of non-kosher taste (Taz, YD 98:2). 2. One may only stick out his tongue to taste but may not put the liver in his mouth (see Pitchei Teshuva ibid.). 3. If it is almost always kosher, it is permitted to taste to make sure (Shach, YD 42:4). However, the consensus is that it is forbidden to taste even a rabbinically prohibited, fully edible food by putting it into the mouth. This is even clearer if one is tasting it in order to enjoy the taste.
Therefore, for two reasons, you may not taste the non-kosher wine.