Beer is composed mostly of <answer>water</answer>. Regions have <answer>water</answer> with different mineral components; as a result, different regions were originally better suited to making certain types of beer, thus giving them a regional character. For example, Dublin has hard <answer>water</answer> well-suited to making stout, such as Guinness; while the Plzeň Region has soft <answer>water</answer> well-suited to making Pilsner (pale lager), such as Pilsner Urquell. The <answer>water</answer>s of Burton in England contain gypsum, which benefits making pale ale to such a degree that brewers of pale ales will add gypsum to the local <answer>water</answer> in a process known as Burtonisation.
What is the main ingredient in beer?
water