Question: Our custom is that on Shabbat, after the head of the household slices the bread, in order to distribute the bread among the many guests, he throws a piece to everyone around the table. Is this custom halachically correct?
Answer: The Gemara (Berachot 46a) states that regarding the blessing on the bread made on Shabbat, the head of the household should not honor anyone else with reciting this blessing; rather, he should do so himself, break the bread, and give it out to everyone seated at the table. The reason for this is in order for him to give out generous pieces, about the size of an olive’s volume, to all those seated. (The holy Zohar, Parashat Ekev, discusses another reason for this based on Kabbalah). Thus, the custom that the head of the household slices the bread and gives out to everyone is indeed a fine custom. This is the prevalent custom throughout the Jewish nation.
We must now discuss the fact that the head of the household throws a piece to everyone seated at the table. Indeed, Tosafot (Berachot 50b) state that throwing bread is forbidden, even when the bread will not get ruined as a result, for bread retains a unique stringency and must be treated with respect; throwing it is certainly disrespectful. Several other Rishonim rule accordingly.
On the other hand, the Rashba quotes Rav Hai Gaon who rules leniently regarding throwing bread if does not get ruined as a result, just as it is permissible to throw other foods that do not get ruined (like throwing wrapped candies at a joyous event). This is not considered disrespecting the bread.
Halachically speaking, Maran Ha’Shulchan Aruch (Chapter 171) rules that bread may not be thrown from one place to another, even if it will not get ruined as a result, since throwing is considered extremely disrespectful, even more so that other usages of bread. It goes without saying that we follow the ruling of the Shulchan Aruch.
Nevertheless, there were great Chassidic Rebbes who would customarily throw pieces of bread to those assembled, especially when the table was very long. The are several Acharonim who have supported this custom. Indeed, Hagaon Harav Chaim of Sanz (in his notes) writes that since this is permissible according to the majority of Rishonim and this is the prevalent custom, there is room for leniency. However, even he writes that one should abstain from throwing the bread wherever possible.
This is especially true regarding the bread upon which the blessing is recited on Shabbat about which the Peri Megadim (quoted by Mishnah Berura, Chapter 197, Subsection 88) states that according to all opinions, it may not be thrown, for this is considered degrading to the Mitzvah. It is therefore appropriate that every G-d-fearing person abstain from throwing the bread at the Shabbat table, for this stands in contrast with the simple understanding of the words of the Poskim (especially since degrading bread can cause poverty, G-d-forbid).
Summary: The head of the household should recite the blessing, break the bread, and give out a generous piece to each person sitting at the table. One should not throw the bread; rather, it should be passed around in a plate or any other manner.