1. One may recite Havdalah on "Chamar Medinah," a beverage that is formally served in that country.
2. Rav generally advised against using beer for Kidush or Havdalah.
3. The Gemara's law concerning beer includes many types of beer.
4. Rav himself eventually recited Kidush on beer.
5. Rava drank a lot of wine on Erev Pesach.
A BIT MORE
1. When Ameimar was a guest in a certain country, he recited Havdalah on beer when wine was not available, because he realized that beer was considered "Chamar Medinah" in that country.
2. Rav Huna: Perhaps beer may be used for Havdalah even if it may not be used for Kidush. Rav Chisda: Beer may not be used even for Havdalah.
3. This refers to barley, fig, and date beer, with date beer being considered the least formal drink of the three.
4. It seems that later in his life, Rav appreciated beer, and therefore he used it even for Kidush, and even when he had wine.
5. This is because drinking a lot of wine increases one's appetite for Matzah. One is not permitted to drink a small amount of wine on Erev Pesach.