I couldn't speak to WWII, but beer sales suffered badly during WWI. In 1917 America, beer was seen as German drink by the American public. Most brewers were German and most German immigrants and German-Americans drank beer. Beer was labelled in propaganda and political cartoons as a German vice (ignoring the fact that beer isn't exclusively German). Anti-German sentiment during the war was actually one the reasons Prohibition was passed in the immediate aftermath of WWI.