If you eat mayonnaise with everything, or you attended Breuers, or you wash your hands before Kiddush, you are probably of German Jewish descent. The first two inferences are understandable. Where does the third one come from?
The Talmud quotes the following passage of Rav Bruna in the name of Rav: “One who washes his hands for bread before reciting Kiddush on Friday night should not recite Kiddush himself, but should rather fulfill his Kiddush obligation by having someone else recite Kiddush for him.” The reason for Rav Bruna’s ruling, as explained by the Rashbam, is that there should be no interruption between washing one’s hands – netilat yadayim – and eating bread.
Reciting Kiddush between the two acts would, according to Rav Bruna, constitute an interruption. Accordingly, if one did wash one’s hands and then recite Kiddush, according to Rav Bruna as explained by Rashbam, one would have to wash one’s hands again before eating bread.
This passage in the Talmud is the source on which the poskim of the “Kiddush before netilat yadayim” camp rely. These poskim include the Rambam (Spain, Morocco and Egypt), the Shulchan Aruch (Spain and Turkey), and the Vilna Gaon (Lithuania). According to both the Rambam and the Shulchan Aruch, the consequence of inadvertently performing netilat yadayim before Kiddush on Friday night is that one would have to recite Kiddush over bread instead of wine. That way, Kiddush would not be considered an interruption.
Leading the “wash before Kiddush” camp are Rabbeinu Tam and the Ri (both of France), the Rosh (German origin) and the Rema. Based on a remark of Rabbi Yitzchak, who observed Rav washing his hands before reciting Kiddush over bread, they point out that the recital of Kiddush after netilat yadayim and before eating bread does not constitute an interruption. This is because the halacha rules in favor of Shmuel, who maintains that Kiddush must be recited over food – ein Kiddush ela bemakom seudah – and against Rav, who maintains that Kiddush can be recited in the absence of food.
Accordingly, Shmuel considers both the bread and the wine an integral part of the Kiddush, and the recital of Kiddush between netilat yadayim and eating bread is not considered an interruption. Even the “wash before Kiddush” camp agrees, however, that the wine should be poured prior to netilat yadayim, since the mental concentration required for measuring out the correct quantity of wine for Kiddush would be considered an interruption.
It appears that customs can differ even in the same family. Indeed, the Tur expresses reservations about the Rosh, his father, whose minhag seemed to ignore the position of Rav as described above.
There is also an in-between position taken by the Chofetz Chaim. He suggests that all those hearing Kiddush may perform netilat yadayim before Kiddush, whereas the person reciting Kiddush should wash after Kiddush.
My father, Dayan Grunfeld, zt”l, seemed to follow an inconsistent approach. He would recite Kiddush before netilat yadayim on Friday night, and perform netilat yadayim before reciting Kiddush on Shabbat morning. I always attributed that to dual loyalties. Though born in Germany, he learned with Polish and Sephardi Rabbis. Only much later did I discover there was more to it. He was in fact following the opinion of the Tur.
According to the Tur, the longer Kiddush of Friday night constitutes an interruption between netilat yadayim and eating bread. The shorter Kiddush of Shabbat morning, however, which requires only the recital of Boreh Pri Hagafen, does not.