Q. The Halacha states that, unlike Birchos HaMitzvos where I can be Motzi another with the Brocho even though I am not fulfilling the mitzvah presently, if I am not eating the food, I cannot be Motzi another with a Brocho on that food.
That said, how can a Rav, who is being M’sader Kiddushin, make the Brocho of Borei Pri HaGofen before Birkas Eirusin and then not, according to Minhag Ashkenaz, drink some wine? True, there are some fringe groups whose custom is to spill some wine while holding the Kos and then lick the wine off his hand after the Brocho. However, for one, this certainly was never the Minhag and secondly, it is certainly unmannerly to lick wine off one’s hand, certainly in public, and I cannot imagine that our Gedolei HaPoskim ever behaved in such.
A. Pnei Yehoshua (quoted by Pischei Teshuvo E.H. 34: 5) addresses this question and considers whether this is in principle a birchas hamitzvos, since the drinking of the wine is not for the pleasure of drinking but rather it is obligatory for the compliance of the mitzva.
Sdei Chemed (A. D. Brochos 3: 5) after mentioning that the Rambam (Peer Hador 1: 1) seems to maintain that the one who recited hagafen should drink, wonders on the minhag of the Ashkenazim why they don’t.
Afikei Yam (2: 2) questions why in our days, when many grooms and brides, either do not understand the concept of someone reciting a brocho for them, or they simply are not paying attention, and therefore if the mevorech does not drink, he would indeed be reciting a brocho in vain. He quotes a source that Rav Chaim Soloveitchik zt”l would spill some wine in his hand. However, Moznaim Lamishpot (1: 12), mentions that he consulted with with his son the Brisker Rov zt’l, and he responded he never saw his father do the above. However, Poskim do mention this tradition. Divrei Tzedek (58: 5), mentions that the Rabbis of Yerushalaim, R.Ch. Zonenfeld and R. S. Salant zt”l would also spill some wine on their hand and lick it. (See Yabia Omer 5: 10″ 7, and Otzar Haposkim 34: 13 that also quotes many Poskim that maintain the minhag Ashkenaz). Yeshuos Yaakov (62: 2) also maintains that the brocho is obligatory. and similar to all brochos of mitzvos, and the mesader kiddushin does not need to drink the wine.
On question 1246 in regards to a case where the mother of the kalah, after receiving the cup of wine given to her to pass it to her daughter, by mistake drank the whole cup herself, we answered: “Horav Shlomo Miller’s Shlit’a opinion is that it is of no consequence, since the brochos were recited over a kos yain and the chosson already drank from it.
The same would apply if the cup spilled after the end of the brochos and only a few drops were drank by the chosson. The brocho recited on the wine would not be considered in vain.
If the cup of wine spilled completely, before the brochos ended. The Rov advises to refill the cup again and have someone else, from the guest recite a new brocho at the end. He should spill a few drops on his fingers and thus have some of the wine, before the chosson and the kallah drink.”
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a