Beer has been around since ancient times, and today it's so popular that it has become the third most consumed drink after water and tea. Beer production is a multi billion dollar industry, and over 35 billion gallons of beer are sold each year.
Beer is most commonly made from four key ingredients: water, barley, hops, and yeast.
Different types waters are suited for various kinds of beer. For instance, the hard water in Dublin, Ireland is perfect for making Guinness stout, whereas the soft water in Plzen, Czech Republic is ideal for making Pilsner Urquell pale lager.
Barley is malted by soaking it in water, where it begins to sprout before being dried in a kiln. Variations in roasting temperatures and times result in different colored malts. Dark beers are made with darker malted barley.
Hops is the flower of the hop vine. It gives beer its characteristic herbal, citrus, and floral flavors and aromas. It also provides bitterness and acts as a preservative.
Yeast is a microorganism that is essential to beer brewing because it enables fermentation. Yeast metabolizes the sugars in grain, producing alcohol and carbon dioxide.