Anthropologists believe the art and science of beer-brewing began before written history. The Beer Institute, a national organization that represents the beer industry before Congress, states on its Web site that beer was probably first created when some nomadic hunter-gatherers left grain out in the rain. Apparently the wet grains fermented, and then "some adventurous soul among these primitive people sampled the liquid, and found that it tasted good."

Today, homebrewers have access to precise brewing equipment and many ingredient options. These ingredients, combined in various combinations, can produce many distinct styles of beer. These styles were invented by brewers throughout the world at different times in history.

Writer, traveler and beer connoisseur, Michael Jackson not the pop star began his career in beer when he wrote the "World Guide to Beer" in 1977. On his Web site www.beerhunter.com he describes more than 70 styles of beer found around the world. Most of these styles can be produced by homebrewers. Some of the more popular varieties include:

Barley Wine: An extremely potent ale that can range from golden copper to dark brown in color. Heavy on caramel malt flavors balanced by copious amounts of bittering hops. More of a dessert beverage than other beer styles. High in alcohol content and usually aged for more than a year before consumption.

Bitter: Standard ale style originally produced in England, and now adopted by many U.S. craft brewers. Characterized by a fruitiness, light to medium body and an accent on hop aromas more than hop bitters. Colors range from golden to copper.

Pale Ale: Fuller-bodied version of a standard bitter with a more assertive character and an amber hue. Often hoppy in the U.S. using Pacific Northwest hop varieties. A standard style among most craft brewers, and a popular and simple to brew variety among homebrewers.

Pilsner: The Pilsner style originated in the Czech Republic and is medium to medium-full bodied and highly carbonated. Many of the Czech varieties of hops impart floral aromas, with a crisp, bitter finish. A refreshing variety with medium alcohol content.

Porter: Popular red-brown to black beer with medium to medium-full body. Wide variations exist among brewers from very subtle dark, malty flavors to fully roasted, smoky flavors. Hops are used primarily as balancing agents. Porters were the drink of the masses of the 1700s London. Today, most good examples of this variety are produced in the U.S.

Scotch Ale: Full-bodied and malty with low hop content with a slightly viscous and sweet caramel malt character. Originally exported from Scotland now adopted by U.S. brewers and brewed stronger.

Stout: Many varieties of this style exist from the sweet stout to what is known as a dry stout. The dry variety is closely associated with Ireland and the Guinness company. These beers tend to be rich and dark with a bitter note and a dry feel. Often nitrogen-flushed at bars to give it the tell-tale white creamy head. Lower in alcohol content than many people think, around 4.5 percent. A typical domestic beer, like Budweiser, is about 3-3.5 percent.

Hefe Weizen: German for wheat beer. Brewed with at least 50 percent wheat. Ideal for summer these beers are refreshing, highly carbonated with a spicy, clove-like flavor. Medium to medium-full body.