Beer

Beer is one of the oldest human-produced beverages, dating back to at least the 7th millennium BC, and recorded in the written history of Ancient Egypt and Mesopotamia. Earliest known chemical evidence of beer dates to circa 3500-3100 BC. Since almost any substance containing carbohydrates, namely sugar or starch, can naturally undergo fermentation, it is likely that beer-like beverages were independently invented among various cultures throughout the world.

A common method of categorizing beer is by the behavior of the yeast used in the fermentation process. In this method of categorizing, beers that use fast-acting yeast and leave behind residual sugars are termed ales, and beers that use slower-acting yeast and remove most of the sugars—leaving a clean and dry beer—are termed lagers.

Ale - Modern ale is commonly defined by the strain of yeast used and the fermenting temperature.

Lager - Lager is the English name for bottom-fermenting beers of Central European origin. They are the most commonly-consumed beer in the world.

Lambic beers - Lambic beers use wild yeasts, rather than cultivated ones. Many of these are not related to brewer's yeast (Saccharomyces), and may have significant differences in aroma and sourness.