Almost any sugar or starch-containing food can naturally undergo fermentation, and so it is likely that beer-like beverages were independently invented in cultures throughout the world. In Mesopotamia, the oldest evidence of beer is on a 6000-year old Sumerian tablet which shows people drinking a beverage through reed straws from a communal bowl. Beer is also mentioned in the Epic of Gilgamesh, and a 3900-year old Sumerian poem honoring the brewing goddess Ninkasi contains the oldest surviving beer recipe, describing the production of beer from barley via bread. Beer became vital to all the grain-growing civilizations of classical antiquity, especially in Egypt and Mesopotamia.
Beer was important to early Romans, but during Republican times wine displaced beer as the preferred alcoholic beverage, and beer became considered a beverage fit only for barbarians. Tacitus wrote disparagingly of the beer brewed by the Germanic peoples of his day.
Most beers until relatively recent times were what we would now call ales. Lagers were discovered by accident in the sixteenth century when beer was stored in cool caverns for long periods; they have since largely outpaced ales in volume. (See below for the distinction.) The use of hops for bittering and preservation is a medieval addition. Hops were cultivated in France as early as the 800s. The oldest surviving written record of the use of hops in beer is in 1067 by Abbess Hildegard of Bingen: "If one intends to make beer from oats, it is prepared with hops." In 15th century England, an unhopped beer would have been known as an ale, while the use of hops would make it a beer. Hopped beer was imported to England (from the Netherlands) as early as 1400 in Winchester and hops were being planted on the island by 1428. The Brewers Company of London went so far as to state "no hops, herbs, or other like thing be put into any ale or liquore wherof ale shall be made — but only liquor (water), malt, and yeast." However, by the 16th century, "ale" had come to refer to any strong beer, and all ale and beer were hopped.
Methods of brewing changed very little from that time. In 1953, New Zealander Morton W Coutts developed the technique of continuous fermentation which was the first major change to brewing since the 16th century. Morton patented his process which revolutionized the industry by reducing a four-month long brewing process to less than 24 hours [1]. His process is still used by many of the world’s major breweries today, including Guinness.