Brewing+Process

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**Malting**
Malting is the process of preparing barley for brewing. It is comprised of three steps, with each step unlocking the starch within the barley. The steps are:

**1) Steeping** The barley is sprayed with water and soaked for about 40 hours.

**2) Germination** The soaked barley grows rootlets in the germination room. A large number of enzymes, such as α- and β- amylase, are used to convert the grain into sugar. The goal of germination is to break the starches into shorter length molecules.

**3) Kilning** After the germination, the barley is dried up in a kiln to preserve the enzymes in the grain. It is important to note that the flavour of beer is related to the temperature at which it is kilned. A higher temperature results in a heavier flavour.

Milling is the cracking of the grain from malting. This is done so that the starch has a greater surface area, allowing it to contact enzymes in the mashing processing.

**Mashing**
This step serves to convert the starch, from the malting process, into sugar. There are two types of mashing.
 * Infusion Mashing: the starch is mixed with hot water and delivered to a cooking vessel called a mash tun. The mash is directly heated by water to achieve temperature changes. Grist, the grain separated from the shell, is coarsely ground, making a high proportion of well modified malt.
 * Decoction Mashing: is carried out with more finely ground grist. A portion of the grains is passed to a series of vessels and returned to decoction mashing vessel, where the grains are heated to boiling.

At the end of the mashing, the sugar-rich water that is strained through the bottom of the mashing tun is called wort.

Brewing
The wort is sent to a brew kettle called COPPER, where it is boiled. During the wort boiling process, hops, which are the female cones of hop plants, are added to create the bitterness, flavour and aroma of beer. A number of changes occur in the wort, such as coagulation of protein, evaporation of the wort, and flavour and colour changes. In this process, it consumes about half of the energy in the brewing process.

<span style="font-family: Arial,Helvetica,sans-serif;">Cooling
<span style="font-family: Arial,Helvetica,sans-serif;">After the brewing, the wort is filtered and quickly cooled to a point that yeast can be safely added. This is the preparation of fermentation. The yeast does not grow in a high temperature condition.

<span style="font-family: Arial,Helvetica,sans-serif;">**Fermenting**
<span style="font-family: Arial,Helvetica,sans-serif;">During this step, the yeast metabolizes substances that can be dissolved in the wort. The major products of carbohydrate metabolism are ethanol, carbon dioxide and heat. The yeast multiplies around 3 to 5 times during this process. The following is the diagram of the fermentation metabolism of glucose.

<span style="font-family: Arial,Helvetica,sans-serif;">The overall chemical reaction: [5] <span style="font-family: Arial,Helvetica,sans-serif;">C <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">6 <span style="font-family: Arial,Helvetica,sans-serif;">H <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">12 <span style="font-family: Arial,Helvetica,sans-serif;">O <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">6 <span style="font-family: Arial,Helvetica,sans-serif;">--> 2C <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif;">H <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">5 <span style="font-family: Arial,Helvetica,sans-serif;">OH + 2CO <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> + E

<span style="font-family: Arial,Helvetica,sans-serif;">Where: <span style="font-family: Arial,Helvetica,sans-serif;">C <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">6 <span style="font-family: Arial,Helvetica,sans-serif;">H <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">12 <span style="font-family: Arial,Helvetica,sans-serif;">O <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">6 <span style="font-family: Arial,Helvetica,sans-serif;"> is the glucose. <span style="font-family: Arial,Helvetica,sans-serif;">C <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif;">H <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">5 <span style="font-family: Arial,Helvetica,sans-serif;">OH is the alcohol. <span style="font-family: Arial,Helvetica,sans-serif;">CO <span style="font-family: Arial,Helvetica,sans-serif; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> is the carbon dioxide <span style="font-family: Arial,Helvetica,sans-serif;">E is the chemical energy.

<span style="font-family: Arial,Helvetica,sans-serif;">This reaction is exothermic, and the chemical energy is utilized in the enzymes growth process.

<span style="font-family: Arial,Helvetica,sans-serif;">Conditioning
<span style="font-family: Arial,Helvetica,sans-serif;">At this stage, the beer is referred to as “green beer,” or immature beer, because the flavour of the beer is not of acceptable quality. The immature beer has to be held for a period of time to refine the flavour of beer. Sometimes, sugar or a small amount of wort is added to boost the yeast metabolism. In this process, the acidic gas hydrogen sulfide is released from beer.

<span style="font-family: Arial,Helvetica,sans-serif;">The following figure schematically illustrates the entire brewing process.



<span style="font-family: Arial,Helvetica,sans-serif;">The brewing process involves many biochemical reactions. It is very complex. The products from the brewing are not only carbon dioxide and alcohol, but they also include the following by-products:


 * <span style="font-family: Arial,Helvetica,sans-serif;">acetaldehyde (green apple aroma)
 * <span style="font-family: Arial,Helvetica,sans-serif;">phenolic (flavour and aroma of medicine, plastic, Band-Aids, smoke, or cloves)
 * <span style="font-family: Arial,Helvetica,sans-serif;">solvent (reminiscent of acetone or lacquer thinner)
 * <span style="font-family: Arial,Helvetica,sans-serif;">hydrogen sulfide (reminiscent of rotten eggs or burnt matches)