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MALTING:  Cereal, usually barley, is converted into malt form, from an extract is obtained for fermentation.  Untreated barley produces an inferior wort (extract).  Wort is grain steeped in water and germinated under controlled conditions develops a complex of enzymes, facilitating production of satisfactory wort.  The steeping stage usually takes from 40 to 80 hours, under controlled conditions of temperature (usually 55 to 59 degrees) and oxygenation.  Alkalinity is sometimes controlled by the use of limewater.  The grain, with water content ranging from 12 to 14 percent depending on storage conditions, is allowed to take up further moisture to a level of 35 – 45 percent, depending upon the procedure to be used for the later part of the malting process.


Grain is sometimes dormant, exhibiting some unwillingness to germinate.  Dormancy exhibits two phases.  The first, common is all barleys, is evident for a few weeks immediately after harvesting, disappearing spontaneously during storage.  Some barleys, especially those grown in maritime climates, retain a second type of dormancy, or “water sensitivity,” and benefit from steeping to a low moisture content level, with more water being added after an air rest period. 


In traditional malting, steeping grain is spread on the floors after draining.  It is piled in thick heaps, or “couches,” to initiate germination and, after about 24 hours, is spread more thinly, either by hand or mechanical raking, to moderate the temperature, which is maintained by the maltster at 59-77 degrees.  Temperature depends on the nature of the malt being produced.  In modern operations, the malting floors have been replaced by mechanical devices, such as; Saladin boxes and drums.  These devices allow the maltster to control the contents and the temperature by rotating the contents and steaming the contents.  Malted wheat, rye, and oats are used to improve the wort.  Malting takes advantage of the enzymes produced by the young plant.  Most malt contains about 45 percent water after germination.  They will be dried and given additional heat treatment, or “curing,” before use.  Kilns turn the malt so that the rootlets are rubbed off and also provide adequate hot air distribution.  Kilning consists of two parts; a phase of drying to about 10 percent of moisture at not more than 45 – 50 degrees and another phase, the curing phase where the malt is heated to well over 100 degrees.  Malted barley is first crushed in the mill and then conveyed to the mash tun.


MASHING:  When brewing, the malt is ground in roller mills to provide a suitable mixture of husks, flour, and grits, then mixed with hot water, depending on the procedure used.  The hot water contains large amounts of calcium and magnesium salts.  The temperature is controlled through simple operating steps.  The whole process is carried out either in a single vessel (infusion mashing) at 144 – 155 degrees as in ale brewing, or in an arrangement in decoction mashing for lager brewing.  This method a portion of the mash is withdrawn to the “mash kettle,” the portion is boiled and then poured back into the main mash.  By repeating this step over and over, the mash eventually gets to 144 degrees.  Some brewers wait till there mash gets up to 167 degrees.


Mashing is largely a chemical process in which the malt enzymes act to convert the starch to a mixture of soluble carbohydrates.  Ninety-seven percent of the starch is extracted.  The wort for an average type of beer consists of perhaps a 10 percent solution of carbohydrates, about three-fourths of the carbohydrate material being fermentable sugar.  It also contains about .08 percent of nitrogen, important in managing both the fermentation and the final beer quality.  The barley is mixed with hot water, creating a mash.  The sweet fermentable liquid from the mash is called wort.  Which is caught by using screen plates and filtered into the kettle.  While the wort is running off, more hot water is sprayed in a process called sparging. 


WORT BOILING:  The wort is next boiled with hops.  This process that about 2 to 3 hours in large “kettles.”  The amount of hops vary, depending on the beer being brewed, some brews use 200 grams while other beers take up to 700 grams.  Boiling regulates composition and sterilizes the final wort so that some protein coagulates, removing a proportion of tannin, and the wort acquires the desired bitterness from the uptake of hop resins.  This is a process similar to making coffee.  Once the mixture is in the kettle, it is boiled.  Ales use top-fermenting yeast, so during this process the yeast will raise to the top of the mixture.  Where as in lagers, bottom-fermenting yeast is used so the yeast settles at the bottom of the fermenter.  At the end of 3 – 4 days the yeast has utilized the sugars from the wort giving off CO2 and alcohol.


FERMENTATION:  Bittered wort, after any necessary storage at a high or a low temperature to inhibit infection, is brought to a selected temperature and transferred into a large open or closed vessel for fermentation.  The wort is “pitched” with selected yeast used in varying forms of moisture content from “liquid” to “pressed.”  After one hour the wort is cooled in the fermenter.  Once the mixture is in the fermenter, yeast is added.    At the end of the fermentation process, cooling begins and the yeast is settled out.  Beer flavors are determined at this stage, called secondary fermentation, during the 7 – 14 days of storage.  After aging the beer, it is cooled to 36 degrees F. for 24 hours.  Under pressure, the beer is transferred through cullulose sheets in the filter press.  This removes protein haze and yeast into a serving tank.  At this point, the beer is filled into the containers in which it will be sold in; kegs, bottles, or cans.

Beer Brewing Process



The Art of Beer

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