REACTIONS INVOLVED IN BREWING BEERBeer brewing has been known since the very beginning of human civilization. Continuing to this day, the widely used process has remained largely unchanged. Beer typically contains around 450 chemical compounds. The flavors and aromas of different types of beer result from changes in these compounds. The main ingredients in beer brewing are malted barley, hops, yeast and water. The brewing process begins with malted barley, which is the main ingredient. This, once ground and heated, produces a sweet liquid rich in proteins called must. Wort is an ideal medium for yeast growth. The yeast then converts the sugars in the malt into alcohol, called fermentation. In relatively recent times, hops began to be added to boiling wort. Hops are responsible for the bitter flavor and characteristic aroma of beer. The brewing process includes several important steps:1. MaltingBrewing can use barley, corn or wheat as the main ingredient. However, barley is the most commonly used grain. As we said before, the major ingredient in beer is malted barley. So brewing begins with the malting of the barley. Barley cannot be used as is to produce the solution called mash. In fact, the starch contained in the flour contained in barley is insoluble. This requires malting the barley. Malting also involves several stages. The first of these is soaking. In this step, the barley seeds are left to soak in water for around 40 days. The second stage is germination. The barley plant took 3 or 4 days to germinate. In this process, enzymes are produced that break down starch (large molecules) into molecules of shorter length. If continued, the natural germination process will have a conversion...... middle of paper ...... polyvinylpolypyrrolidone stabilizer that prevents polyphenols from combining with proteins. The result of flavor instability is that the beer will usually end up tasting like cardboard. This is attributed to trans-2-nonenal. This is the result of an oxidation reaction whose exact process is unknown. It is important to minimize the oxygen content of the beer as much as possible during brewing to avoid a stale taste. Many opt for bisulfate because it is a natural antioxidant and can counteract the compounds responsible for flavor instability. However, bisulfate is ultimately converted to sulfate and therefore is not a permanent solution to the problem.8. FinishingFinally, the beer is filtered and carbonated. After this step, it is stored until bottled or canned.References1. http://www.esu.edu/~scady/mueller/home.htm2. http://www.alabev.com/brew.htm