To make beer, brewers use water and barley to create a sweetened liquid (called the wort), which they flavor with hops, then ferment with yeast. The basic process may be simple but the execution is highly sophisticated. The stages are malting, milling, mashing, brewing, cooling and fermentation – followed by maturation (racking), filtering (finishing) and packaging.
*Information courtesy of http://www.alabev.com
1. Malting is the process of readying barley to be used in brewing. Barley is a tall grass with seeds on the top of the stalk. Barley is not good for baking but is good for brewing beer. Barley comes in many strains and varieties that ultimately influence the flavor of the beer. Barley cannot be used to create the wort in its normal state, because the starch in its floury kernel is insoluble. Each step of the malting process unlocks the starches hidden in the barley. Steeping is the first step in malting. Here the grain is steeped (soaked) in a vat of water for about 40 hours. The next step is germination of the barley grain. To germinate the barley, the grain is spread out on the floor of the germination room for about three to five days where rootlets begin to form. Inside the barley is a substance called starch. If left alone, the barley seed develops enzymes (chemicals) to break down the starch into sugars. The barley plant would use that sugar as energy to grow leaves and once the sugar supply is used up, the sun would take over growing a new barley plant. The germination process produces the enzymes which break down the starches within the grain into shorter lengths. At the end of the germination process, about three days, the starch has become soft and the enzymes have not started converting the starch into sugar yet. The barley grain is called green malt.
The next process is drying or kilning. Once the plumule or rootlets below the husk grow to three quarters the length of the grain, germination is halted by drying the green malt on metal racks in the kiln house at 50° C. The temperature is then raised to 85°C for a light malt, or higher for a dark malt. It is important that temperature increases are gradual so that the enzymes in the grain are not damaged. The malt shoots are removed for cattle feed, and the dried malt is stored in silos. Although malted barley is the primary ingredient, unmalted corn, rice or wheat are sometimes added, to produce different beer flavors.
After kilning, the result is finished malt. The differences in the way the barley is malted will affect the flavor, color and aroma of the beer. There are different types of malts: pale malts are dried at a low temperature and can produce a malt that can give the beer a pale golden color and a slightly bready flavor such as a pilsner. Mild ale malts are kilned to a slightly higher temperature and produce a pale malt that gives the beer a deeper color and slightly toasted biscuit flavors in the final beer. Many English ales go for this malt profile. Vienna and Munich malts are stewed and lightly kilned which converts some of the starch into more sugar which give the beer an orangey amber color and the classic toffeeish, nutty flavors of Oktoberfest beer and other Bavarian, German specialties. The highest temperatures are used to produce very flavorful and aromatic malts. Caramel and Crystal malts are stewed until all of their starches are converted into sugars then they are kilned until the sugar caramelizes like little Sugar Daddy candies. This longer roasted, sweet, caramel-flavored malt gives the beer a reddish-amber color, rich flavors and a fuller body. Kiln the barley longer and at higher temperatures and the darker and “roastier” the beer will be. (Just like higher roasted coffee beans.) This will give the beer darker color and chocolate, coffee and espresso-like flavors.
2. Milling is the next step. Milling is the cracking of the grain which the brewer chooses for the particular batch of beer. Milling the grain allows it to absorb the water it will eventually be mixed with in order for the water to extract sugars from the malt.
3. Mashing is the next step. Mashing is the process of turning the finely-ground malt, the grist, into a sweetened liquid. Mashing converts the starches, which were released during the malting stage, to sugars that can be fermented. The milled grain is dropped into warm water then gradually heated to around 75° C in a large cooking vessel called the mash tun. In this mash tun, the grain and heated water mix creating a cereal mash to dissolve the starch into the water, transforming it into sugar – mainly maltose. Because water is such a vital part of the brewing process, the water itself is a key ingredient. This sugar rich water is then strained through the bottom of the mash and is now called wort. (Pronounced wert.)
4. Brewing is the next step. The spent grains are filtered out and the wort is ready for boiling which involves many technical and chemical reactions. During this stage, important decisions will be made affecting the flavor, color and aroma of the beer. Certain types of hops are added at different times during the boil for either bitterness or aroma and to help preserve it. The wort is boiled for one to two hours to sterilize and concentrate it, and extract the necessary essence from the hops.
5. Cooling is the next step. The wort is transferred quickly from the brew kettle through a device to filter out the hops, and then onto a heat exchanger to be cooled. The heat exchanger basically consists of tubing inside of a tub of cold water. It is important to quickly cool the wort to a point where yeast can safely be added, because yeast does not grow in high heat. The hopped wort is saturated with air, essential for the growth of the yeast in the next stage.
6. Fermentation is the next step. After passing through the heat exchanger, the cooled wort goes to the fermentation tank. The brewer now selects a type of yeast and adds it to the fermentation tank. This is where the “real magic” of brewing happens – when the yeast, which is a micro-organism, eats the sugar in the wort and turns it into alcohol and carbon dioxide. This process of fermentation takes ten days. The wort finally becomes beer. Each brewery has its own strains of yeast, and it is these that largely determine the character of the beer. In some yeast varieties, the cells rise to the top at the end of fermentation, and are then skimmed off. This is called top fermentation, and ales are brewed in this way. When at the end of fermentation the yeast cells sink to the bottom, the process is known as bottom fermentation, used for lager or pils. Some special Belgian beers, called lambic or gueuze, use a third method where fermentation relies on spontaneous action by airborne yeasts typical of the Zenne valley near Brussels.
7. Maturation (also called racking) is the next step. The beer has now been brewed, but it can still be improved through maturation. During this phase, the brewer moves, or racks, the beer into a new tank called the conditioning tank. The brewer then waits for the beer to complete its aging process. The taste ripens. The liquid clarifies as yeast and other particles settle. Secondary fermentation saturates the beer with carbon dioxide.
8. Finishing is the last step in the brewing process. Here the beer is filtered and carbonated. Further filtering gives the beer a sparkling clarity. The beer is moved to a holding tank where it stays until it is bottled, canned or put into kegs. Filling techniques ensure air does not come into contact with the beer, and cannot be trapped within the container.
The final excellence of the beer you drink depends on you. Drink the beer as fresh as possible, serving it at the right temperature, in clean glasses, and properly poured. Good health!