Beer Brewing
Essay title: Beer Brewing
Beer Brewing
Beer is a common alcoholic beverage that is sold around the world. Although there are many different companies that brew beer, they all follow the same chief steps. The four main ingredients of barley, water, hops and yeast are combined in a fairly long process involving biochemical reactions to produce the drink. There are four basic steps: grain processing, boiling, fermentation, and finally filtering and bottling. Unfortunately, due to the alcoholic content of beer, there are also many ethical, moral and cultural concerns to do with the retail of beer. In addition, there are environmental issues about the disposal of the packaging.
The brewing of beer begins with grain processing of the first ingredient: barley. The grain is soaked in water for several days and then allowed to sprout. When the seed sprouts, enzymes are released which help convert the complex carbohydrates (nutrients/starches within the plant) into simple fermentable sugars. This is a natural process that occurs so that that plant has something to feed on before it can depend on photosynthesis. The trick to the malting is that the germination must be stopped, as the enzymes are present, but before most of the starches have been converted. The next step is kilning, where the grain is dried and roasted. The sprout is killed and the grain is given flavor and color. The intensity of the malt flavor and color is determined by how high the temperature is raised. The malt is then taken to the mill, where steamrollers crush the malted barley and separate the husks from the grain itself. This crushing allows the grain to be better exposed to the boiling water and also helps convert more sugars and kill any bacteria. The last step of grain processing is mashing. A mixture of malts and warm water is placed in the mash tun. This mixture is called the mash and is heated with temperatures that provide favorable conditions for the carbohydrates (long chains of glucose molecules) to be broken down into fermentable sugars. The enzymes in the barley, can convert these starches. Next, the mash is moved to the lauter tun. Here the liquid is separated from the grains, called the wort, and is very sweet and sticky.
The next stage in brewing is called boiling and involves the second ingredient: hops. Hops, are the dried cone like flowers from a plant of the Cannabeae family, and are used as a mild sterilant and to give a bitter flavor to beer. The wort produced in the step before is put into a huge brew kettle and hops are added. The hops add the bitter flavor and aroma to the beer. After the boiling is finished, all the solids must be separated from the liquid. The wort is pumped from the kettle and then forced back into it through a jet nozzle. This flow of liquid then causes a whirlpool to form and all of the solids move to the center and sink. The kettle is then drained leaving solids inside. Next, the wort must be cooled down to an appropriate temperature for the yeast. It is important that this is done quickly to reduce the chance of contamination by stray yeasts in the air.
At this point, the mixture is ready for fermentation and is transferred to the fermenter tank. In this process, the yeast (a single celled micro-organism) is added to the wort. The sugars produced in the earlier steps are consumed by the yeast and are converted to ethyl alcohol and carbon dioxide gas.
Yeast
C6H12O6 ? 2C2H5CH + 2CO2
Enzymes
The sugars are consumed by the yeast, and the reaction is sped up by enzymes. This produces ethanol and carbon dioxide, and the beer has been made.
Some of the CO2 stays in the beer giving the bubbles, otherwise known as carbonation, and some is allowed to escape. The fermenter tank is sealed off from the air, apart from one long narrow vent pipe through which the gas can escape. When the fermentation is complete, most of the yeast will settle at the bottom of the cone shaped tank. It will then be removed and reused for the next batch of beer. Yeast can be reused until it mutates and begins to produce a different taste.
Finally, before retail, the beer must be filtered and pasteurized. The beer is poured over a filter made of pre-historic diatoms that filters half a micron of solids. It is then heated to over 72 degrees Celsius and rapidly cooled to below 10 degrees Celsius. This is important to kill any remaining bacteria in the beer. Finally, the beer is ready to be bottled.
Over time, beer has become an extremely popular drink in society, and in result numerous moral and ethical issues have arisen concerning