Translation:Shulchan Aruch/Orach Chaim/269

It is the custom to recite Kiddush in the synagogue, however, the one who recites does not taste the wine of Kiddush but gives it to a minor to taste because Kiddush is recited at the place where the meal is eaten. From the outset this custom was established for the sake of [communal] guests who eat and drink in the synagogue, so that they may fulfill their obligation. And today, even though [communal] guests do not eat and drink in the synagogue, the custom remains.