We are beginning siman 12. From siman 12 until the end of the Klal, the Chayei Adam will discuss the halachos of reciting hatov vehametiv on wine. The Chayei Adam begins with an introduction.
The Gemara learns from pesukim that mideoraysa, there are three ideas which must be mentioned. These are mazon, the land, and kedushas Eretz Yisrael (which affords us the Beis Hamikdash and so on). These ideas manifest themselves through the brachos of hazan es hakol, al haaretz, and boneh yerushalayim. Chazal added a bracha for the Harugei Beitar, the remnants of Bar Kochva’s army who were killed out by the Romans. After conquering Beitar, the Romans did not allow for the slain soldiers to be buried for many years, but Hashem made a miracle and their bodies remained preserved until they were allowed to be buried. In response, Chazal enacted the bracha of hatov vehametiv; hatov for preserving the bodies, and hametiv for allowing them to be buried. In addition to reciting this bracha in benching, we also recite it when additional wines are brought out at a meal
The Chayei Adam brings a somewhat negative reason for why we say this bracha on wine; the Mishnah Berurah also brings a second, more positive one. The Chayei Adam explains that when a person drinks a second type of wine, Chazal were concerned that a person was on their way to overindulging. Chazal wanted a person to associate wine with Harugei Beitar, so that they would remember that this world is not permanent. Additionally, the Romans used the Jews’ blood to fertilize their fields, so the violence surrounding their death should sober a person and help them maintain the proper perspective when drinking.
The Mishnah Berurah explains that wine is a vehicle of simcha, and we have tremendous appreciation to Hashem for giving us this vehicle of simcha with such an expanse of options.
The Chayei Adam writes that this bracha is only recited when two people are sharing wine together. Additionally, the second wine does not have to be better than the first, but cannot be inferior.