"Hoi," by the way, is not pronounced "hoy" as one might expect, but "huh-ee" (except you say it as one syllable). "Hoy," in fact, means "smelly." So for the first month or so after our arrival, I would sit down at my favorite bia hoi and order up a glass of smelly beer.
Bia hoi is stored in non-pressurized, insulated kegs. They have to sell all the beer by the end of the day because it goes flat, and there is a noticeable difference between a glass tapped from the bottom of a keg and a glass tapped from a new keg.
Note that these kegs are from the local bia hoi producer in Hai Phong. There are a couple of other brands in town, including one from Hanoi that is slightly more expensive. I prefer the local brew though.
In the late afternoon the bia hois begin to fill up and are packed around 8pm (although it is pretty common to see a few beer enthusiasts knocking back some brews as early as 7 in the morning).
Chilling out at a bia hoi involves (continuously) toasting the good health of your drinking companions and enjoying the fact that the heat has broken for the time being (that is if, in fact, the heat has broken; if not then it is a time for simply toasting the good health of your drinking companions--continuously).