An earlier Halacha discussed the possibility of a person reciting Kiddush – or, for that matter, Havdalah – and giving the wine to somebody else to drink. The basic principle is that when one recites the Beracha over a certain food or drink as part of a Mitzvah, such as Kiddush and Havdalah, then he may have somebody else eat or drink the given food or drink. When, however, the Beracha is recited solely for the sake of partaking of the given food or drink, and not as a Mitzvah obligation, a person may not recite a Beracha if he will not be eating or drinking. If a group of people assemble to eat together, one person may not recite the Beracha on behalf of the others if he will not himself be eating.
In light of this principle, the Poskim (authorities on Halacha) discussed the question of whether the Rabbi who recites the Beracha of "Borei Peri Ha'gefen" under the Chupa at a wedding must drink some of the wine. The Beracha of "Borei Peri Ha'gefen" is recited twice under the Chupa, once in each of the two stages of the marriage ceremony – the Kiddushin and the Nisu'in. During the Kiddushin, the Rabbi recites a Beracha over wine in conjunction with the Beracha, "Asher Kideshanu Be'mitzvotav Ve'tzivanu Al Ha'arayot…" In the Nisu'in, the Beracha over wine is the first of the seven blessings recited in honor of the bride and groom. The question thus arises whether the Rabbi who recites the Beracha over wine in either instance must drink some wine, or if it suffices to have the Chatan and Kalla (bride and groom) drink.
According to Halacha, the Kiddushin does not require a cup of wine, and thus the Beracha recited over wine during this stage of the wedding is purely a Birkat Ha'nehenin – a Beracha recited before partaking of food and drink. Therefore, the Rabbi must drink some wine himself, before giving the cup to the Chatan and Kalla. Since he does not recite the Beracha over wine as an obligation, he cannot give the cup to somebody else to drink. Indeed, common practice is for the Rabbi to sip some of the wine after reciting the Berachot during the Kiddushin.
The cup of wine at the Nisu'in, by contrast, is, according to many authorities, obligatory. The Zohar writes very clearly that seven Berachot must be recited at the Chupa, and without the Beracha over wine we are left with only six Berachot. This is the position of the Rosh (Rabbi Asher Ben Yechiel, Germany-Spain, 1250-1327), the Penei Yehoshua (Rabbi Yaakov Yehoshua Falk, Germany, 1680-1756), and others. Therefore, strictly speaking, the Rabbi who recites the Beracha over wine as part of the Sheva Berachot ("seven blessings") under the Chupa does not have to drink any wine. As is the practice of most Rabbis, they may simply recite the Beracha and then hand the cup over to the Rabbi who will recite the subsequent Beracha.
Nevertheless, some Rabbis have the practice of either dipping a finger into the wine or spilling some drops of wine on a finger, and then sipping the wine off the finger. This reason for this practice is the implication of the Rambam (Rabbi Moshe ben Maimon, Spain-North Africa, 1135-1204) that even during the Nisu'in the cup of wine is not strictly obligatory. According to this view, the Rabbi must drink some wine once he recites the Beracha of "Borei Peri Ha'gefen." Some Rabbis therefore make a point of sipping some of the wine after reciting this Beracha, before handing the cup to the next Rabbi. The reason why the Rabbi cannot sip directly from the cup is the law of Pagum – namely, one may not recite a Beracha over a cup of wine from which a person has directly drunk. If the Rabbi reciting the Beracha of "Borei Peri Ha'gefen" would sip directly from the cup, the cup would be unfit for the recitation of the subsequent Berachot. For this reason, Rabbis who want to satisfy the Rambam's position spill some wine on their finger and then sip from their finger.
Chacham Ovadia Yosef disapproves of this practice, arguing that onlookers who are unaware of the Halachic reasons for spilling the wine may look askance at a Rabbi who conducts himself in this manner, possibly resulting in a Chilul Hashem (desecration of God's Name). Therefore, some Rabbis try to sip the wine in an inconspicuous manner. In any event, this is but an additional measure of stringency; strictly speaking, Halacha follows the position that the Rabbi who recites the Beracha over wine during the Nisu'in does not have to drink any of the wine.
Summary: The Rabbi who recites the first Beracha over wine under the Chupa – during the Kiddushin – must drink some of the wine before giving the cup to the Chatan and Kalla for them to drink. The Rabbi who recites the Beracha over wine as part of the "Sheva Berachot" does not, strictly speaking, have to drink any wine. Nevertheless, some Rabbis have the practice of spilling some wine on their finger or dipping their finger into the wine, and then sipping the wine from their finger.
