The largest festival in the world is not just about the food and drinks, as a large part of the grounds are occupied by amusement rides. Another thing to keep in mind is that beer can only be purchased if you are seated at one of the beer-tent tables and cannot be removed from that tent.
While the large grounds are crowded in the evening, the people will not be spilling beer on you as you walk around. Only the six München brauerei may serve beer on the festival grounds. The grounds are easily accessible by numerous means.
Beer is served until 10:30 and closing is at 11pm.