Beer Making Technique – Step by Step Guide on How to Make Beer

Posted by Darren on February 16, 2011 · Leave a Comment

MALTING

Balley Conversion

In order to be fermented by yeast, the food reserve of barley, starch must be converted by enzymes into simple sugars. Two enzymes, a- and b- amylases, carry out the conversion. The latter is present in barley – but the former is made only during germination of the grain.

Steeping

Malting begins by immersing barley harvested at less than 12 percent moisture in water at 120 to 150C (550 + 600) for 40 to 50 hours. During this steeping period, the barley may be drained and given air rests, or the steep may be forcibly aerated. As the grain imbibes water, its volume increases by about 25 percent, and its moisture content reaches about 45 percents. A white roots heath, called a chit, breaks through the husk, and the chitted barley is then removed from the steep for germination.

Germination

Activated by water and oxygen, the root embryo of the barley corn secretes a plant hormone called gibberellic acid, which initiates the synthesis of a- amylase. The a- and b- amylases then convert the starch molecules of the corn into sugars that the embryo can use as food. Other enzymes, such as the proteases and b- glucanases, attack the cell wall around the starch grains, converting insoluble proteins and complex sugars (called glucans) into soluble amino acids and glucose.
Kilning

Green malt is dried to remove most of the moisture, leaving 5 percent in lager and 2 percent in traditional ale malts. This process arrests enzyme activity but leaves 40 to 60 percent in an active state. Curing at higher temperatures promotes a reaction between amino acids and sugars to form melanoidins, which give both colour and flavour to malt.

In the first stage of kilning, a high flow of dry air at 500C (120F) for lager malt and 650C (1500F) for ale malt is maintained through a bed of green malt. This lowers the moisture content from 45 to 25 percent. A second stage of drying removes more firmly bound water, the temperature rising to 700 – 750 (1600 – 1700F) and the moisture content falling to 12 percent. In the final curing stage the temperature is raised to 750 – 900C (1700 – 1950F) for lager and 900 to 1050C for ale. The finished malt is then cooled and screened to remove root lets.

MASHING

Milling

For efficient extraction with water, malt must be milled. Early milling processes used stones driven manually or by water or animal power, but modern brewing uses mechanically driven roller mills. The design of the mill and the gap between the rolls are important in obtaining the correct reduction in size of the malt. The object is to retain the husk relatively intact while breaking up the brittle modified starch into particles.

Mixing the Mash

The milled malt, called grist, is mixed with water, providing conditions in which starch, other molecules, and enzymes are dissolved and rapid enzyme action takes place. The solute-rich liquid produced in mashing is called the work. Traditionally, mashing may be of one of two distinct types. The simplest process, in fusion mashing, uses a well-modified malt, two to three volumes of water per volume of grist, a single vessel (called mashtun), and a single temperature in the range of 620 to 670C (1450 to 1500F). With well-modified malt, breakdown of proteins and glucans has already occurred at the malting stage, and at 650C the starch readily gelatinizes and the amylases become very active. Less well-modified malt, however, benefits from a period of mashing at lower temperatures to permit the breakdown of proteins and glucans. This requires some form of temperature programming, which is achieved by decoction mashing. After grist is mashed in at 350 to 400C (950 to 1050F), a proportion is removed, boiled and added back. Mashing with two or three of these decoctions raises the temperature in stages to 650C. The decoction process, traditional in lager brewing, uses four to six volumes of water per volume of grist and requires a second vessel called the mash cooker.

Other sources of starch that gelatinize at 550 to 650C can be mashed along with malt. Wheat flour and corn (maize) flakes may be added directly to the mash, whereas corn grits and rice grits must first be boiled in order to gelatinize. Their use requires a third vessel, the cereal cooker.

Modern mashing system use mixed grists and mash mixers, which are efficiently stirred and temperature-programmed mashing vessels. Enzymes of bacterial and fungal origin may be added as aids. Ale and lagers are mashed in the same equipment, but they require different temperature programs and grist composition. Modern breweries often practice high-gravity brewing, in which highly concentrated worts are made, fermented, and then diluted, allowing more beer to be brewed on the same equipment.

Separating the Wort

The mashtun used in infusion mashing is fitted with a false base containing precisely machined slots through which the husk, preserved during milling, cannot pass the trapped husk thus forms a filterbed that removes solids from the wort as it is drained, leaving a residue of spent grains. Wort separation takes four to sixteen hours. For through extraction, the solids are sprayed, or sparged, with water at 700C.

The decoction brewer transfers the mash into separation vessel called the lautertun, where a shallow fitter bed is formed, allowing a more rapid runoff time of about 2

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