Brewing is the production of alcoholic beverages through fermentation. This is the method used in beer production, although the term can be used for other drinks such as sake. The term is also sometimes used to refer to any chemical mixing process.
Brewing has a very long history, and archeological evidence tells us that this technique was used in ancient Egypt. Descriptions of various beer recipes can be found in Sumerian writings, some of the oldest known writing of any sort.
The brewing industry is part of most western economies.
The malt is ground into a coarse powder, known as grist, which is mixed with heated water in a vat called a "mash tun" for a process known as "mashing". During this process, natural enzymes within the malt break down much of the starch into sugars which play a vital part in the fermentation process. Mashing usually takes 1 to 2 hours, and during this time various temperature rests activate different enzymes depending upon the type of malt being used, it's modification level, and the desires of the brewmaster. The Mash Tun generally contains a slotted "false bottom" or other form of manifold which acts as a strainer allowing for the separation of the liquid from the grain.
A mash rest at 104 °F or 40 °C activates glucanase, which breaks down gummy beta-glucans in the mash, making the sugars flow out more freely later in the process. A mash rest from 120°F to 130 °F (49°C to 55°C) activates various proteinases, which break down proteins that might otherwise cause the beer to be hazy. But care is of the essence since the head on beer is also composed primarily of proteins, so too agressive a protein rest can result in a beer that cannot hold a head. This rest is generally used only with undermodified (i.e. undermalted) malts which are decreasingly popular in Germany and the Czech Republic, or non-malted grains such as corn and rice, which are widely used in North American beers. Finally, a mash rest temperature of 149 to 160 °F (65 to 71 °C) is used to convert the starches in the malt to sugar, which is then usable by the yeast later in the brewing process. Doing the latter rest at the lower end of the range produces more low-order sugars which are more fermentable by the yeast. This in turn creates a beer lower in body and higher in alcohol. While a rest closer to the higher end of the range creates more higher-order sugars, which are less fermentable by the yeast so a fuller-bodied beer is the result, with less alcohol.
After mashing the resulting liquid is strained from the grains in a process known as lautering. At this point it is known as wort. The Wort is moved into a large tank known as a "copper" or kettle where it is boiled with hops and sometimes other ingredients such as herbs or sugars. The boiling process serves to terminate enzymatic processes, precipitate proteins, isomerize hop resins and sterilize the wort. Hops add flavour, aroma and bitterness to the beer. At the end of the boil, the hopped wort settles to clarify it in a vessel called a "whirl-pool" and the clarified wort is then cooled.
The wort is then moved into a "fermentation vessel" where yeast is added or "pitched" with it. The yeast converts the sugars from the malt into alcohol, carbon dioxide and other components through a process called ""Glycolysis"". After a week or so, the fresh (or "green") beer is run off into conditioning tanks. After conditioning for a week or longer, the beer is often filtered to remove yeast and particulates. The "bright beer" is then ready for serving or packaging.
There are two main families of beer styles determined by the variety of yeast used in their brewing.
Today lagers represent the vast majority of beers produced, the most famous being a light lager called Pilsner which originated in Pilsn Czech Republic. It is a common misconception that all Lagers are light in color but lagers range from very light to black opaque just like Ales.
