2 words: Classical Conditioning
Classical conditioning was made famous by Pavlov when he experimented with dogs. He would measure their salivary response by presenting dogs with food. Initially, the dogs did not begin salivating until the food was presented, but eventually, the dogs began to salivate at the mere sound of the bell: creating an association between the sound of the bell with the presentation of food.
Which is similar to how people acquire the 'taste' for beer. Initially, beer itself doesn't cause a rewarding response, it is the following 'buzz' or events that happens during the buzz (ie, party or sex). But eventually, the beer itself comes to be associated as the reward, and it becomes more appealing. Ever have a beer or cigarette after a long period of not having them (like years)... what goes through your mind when you sit down and have that smoke or beer after such a long period? Floods of memories of 'goodtimes' comes back to you.
It's also why beer ads of scantily clad women are so effective. You'll hear ignorant people saying 'do they really expect that kind of advertisement to be effective... do you really think people think they're at a pool of scantily clad women when they drink Bud'. No, they don't... but when you watch enough of those commercials, you'll come to associate Budweiser as something arousing (consciously or unconsciously). It's also why you see advertisement banners around hockey rings and a big Budweiser ad right in the middle of a boxing ring. It has nothing to do with exposure, but it has everything to do with associating an arousal with a stimulant (excitement of a game with the subliminal message of beer).
Do i like the taste of beer? Not normally, but on a hot summer day and having a grilled steak, i'm dying for one. Why? because all the good times i've had beers were on those type of days. Same thing with cigarettes, i've quit them... but when i'm having a coffee, i'm dying for one because that's how i use to spend my teen years (in coffee shops smoking).