One of the pompous college boys' beer-happy pontifications: "Evil... good. These are moral absolutes that predate the fermentation of malt and fine hops." Technically, in beer-brewing, the hops aren't fermented but added later, as a spice.
In the long pan across all the sinister chemical lab equipment, the final Dimroth condenser out of which the witches' brew drips into the beer barrel is hooked up the wrong way. More to the point, it is not hooked up at all to a cooling water supply, but if it were, then it would need to be connected to the spiral in the center while the product would condense on the outside of the spiral.
Buffy is seen drinking in a bar and served alcohol the legal age in America to be served and to drink Alcohol is restricted to persons of 21 and over Buffy is 18 meaning she's underage and the bar manager would be prosecuted and lose his license.
Xander, Buffy, and Willow get up from the table. The personal microphone equipment clipped to the waistband at the back of Nicholas Brendon's pants is visible; he adjusts his shirt to cover it as they turn to walk.