The practice of brewing beer goes back thousands of years. It was considered a safer beverage than milk or water, and intoxication at parties and banquets wasn't unusual. The four most important elements in beer are water, malt, hops, and yeast. Some breweries carefully guard their recipes and each ingredient affects the taste, color and carbonation of beer. Here is a more detailed breakdown of how beer is brewed. The process hasn't changed all that much since ancient times.
Malting
In some parts of the world, the type of cereal grain used to brew beer will depend on what's available in local markets. Some countries use maize, rice, or even sorghum. Barley is favored by most brewers because it gives the best results. Steeping is the first stage, where barley is submerged in water to initiate germination.
The diastase enzyme is mainly responsible for converting insoluble starch into maltose, the sugar that yeast converts into alcohol and carbon dioxide during fermentation. Kilning is the final step, in which germination is stopped by heating. This is done to prevent the barley grains from sprouting roots. The temperature of the kiln will determine the color and flavor of the beer.
Milling
At this stage of the brewing process, the grains are cracked to expose the sugars contained within. The husks are broken, but are still intact. The reason being is that if the malt is too fine, the beer will look cloudy and taste awful. Milling allows the grain to absorb the water it will be mixed with later on for the purpose of extracting sugar from the malt.
Mashing
A mash tun is a big copper tank in which the starches in cracked grains are converted into sugars for fermentation. At this stage, water is an important ingredient. The milled grains are put into water and left to sit for a time to allow the necessary enzymes to activate this process. The mash tun comes with a screen at the bottom to separate the spent grain husks from the sugary liquid, called wort. To make sure all of the sugars are removed, more heated water is sprayed over the grains. This step is called sparging.
Boiling
This step is critical in beer brewing, because hops are added to impart bitterness. This will help to balance the sweetness of the malt. Without hops, beer would be undrinkable. Another reason for boiling is to destroy any remaining bacteria that would ruin the taste of the beer. How long the boiling stage lasts is up to the brewer.
Cooling
The beer is taken from the brew kettle and cooled at a temperature that is suitable for fermentation. Yeast will not thrive in hot liquid, so a brewer must wait until the wort is sufficiently cooled. A device with copper tubing called a wort chiller is used for this purpose.
Fermentation
The yeast will use the available oxygen in the wort to reproduce, and once that's used up they will feast on the sugars created in the mashing stage. This process creates alcohol and carbon dioxide. Fermentation is important and it's controlled by temperature regulation, the pitch rate, i.e. the amount of yeast put into the tank, and oxygen content. Once this is completed, the beer is transferred to the lagering tanks.
Lagering (Storing)
The beer is almost finished, but before it's suitable for consumption it must be kept cold for long periods to allow the yeast to settle. It could take weeks or months, and during that time pressure is maintained on the tanks to stop the beer from going flat.
Packaging
There is one last phase of pasteurization to inactivate beer-spoiling microorganisms before the beer is put into cans, bottles, and kegs. After that, it leaves the brewery and it's ready to drink.
Scott Hayden - Since joining Suite101 in early 2007, I've contributed articles about travel, history and health. My speciality is writing about workplace ...
