Cool Beer Puzzle

Beer is the world's most widely consumed[1] and likely the oldest[2][3][4] alcoholic beverage; it is the third most popular drink overall, after water and tea.[5] The production of beer is called brewing, which involves the fermentation of starches, mainly derived from cereal grains—most commonly malted barley, although wheat, maize (corn), and rice are widely used.[6] Most beer is flavoured with hops, which add bitterness and act as a natural preservative, though other flavourings such as herbs or fruit may occasionally be included. The fermentation process causes a natural carbonation effect, although this is often removed during processing, and replaced with forced carbonation.[7] Some of humanity's earliest known writings refer to the production and distribution of beer: the Code of Hammurabi included laws regulating beer and beer parlours,[8] and "The Hymn to Ninkasi", a prayer to the Mesopotamian goddess of beer, served as both a prayer and as a method of remembering the recipe for beer in a culture with few literate people.[9][10]

Beer is sold in bottles and cans; it may also be available on draught, particularly in pubs and bars. The brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. The strength of beer is usually around 4% to 6% alcohol by volume (abv), although it may vary between 0.5% and 20%, with some breweries creating examples of 40% abv and above.[11] Beer forms part of the culture of beer-drinking nations and is associated with social traditions such as beer festivals, as well as a rich pub culture involving activities like pub crawling, and pub games such as bar billiards.