Malt
Brewing begins with barley, wheat, oats or rye sprouted in the malt house. The grain is then dried in a dryer and sometimes roasted, a process usually carried out in a separate room from the brewery. In the brewery building, the malt is passed through a crusher to open up the shell of the grains. This helps to extract more starch during the mashing process. Large breweries also use soaking before crushing.
Mashing
The first step in the brewing process is mashing, in which crushed malt (grits) is placed in a mash pot. Mashing is the process of mixing mash with water and heating the mixture to between 40 and 80ºC. During mashing the natural enzymes in the malt break down the starches into sugars which then become alcohol. This process takes on average one to two hours.
Infusion and decoction mashing method
Water is mixed with the grits in one of two ways: infusion or decoction. The infusion mash method involves heating the grain in a single vessel (mash vat); the broth mash method involves removing some of the mash from the mash pot and boiling it in a separate vessel and then returning it to the original mixture. Some brewers repeat this process twice (two-barrel mashing) and even three times (three-barrel mashing).
Decanting
Decanting or wort filtration is the process of separating the wort from the beer grit as efficiently as possible. It is usually carried out in a separate decanting vat, although the mash filtration process is now available to both large and small breweries.
The bottom of the decanting vat has round or longitudinal holes, as well as drain holes. The solids from the mash remain at the bottom and form a filter for the wort.
The decanting process consists of three steps: mash-out, recirculation, and rinsing. Mash-outs consist of heating the mash to 76ºC which stops the fermentative reactions and retains the digestible sugars in the wort and makes the wort less viscous, making further work easier.
Boiling
Once the wort has been made, it is sterilized by boiling in a cauldron. This suspends the activity of the enzymes and evaporates the liquid. During the boiling process, which usually lasts between 60 and 120 minutes, hops are added.
Hops may also be added after brewing during vortexing (flavor/aroma), fermentation (dry hop for aroma), or maturation (dry hop for aroma).
At the end of the brewing process, there is vortex stirring to make the wort even more transparent by removing proteins and hop particles that have settled to the bottom. These particles are called sediment. A digester can be used for whirling, but many breweries have a special vessel for this.
Fermentation
The wort is pumped into a fermentation vat and yeast is added (added) to it. This stage is called basic fermentation – the sugars are converted into alcohol and carbonic acid. The result is an ale or lager, depending on the yeast used. (Hybrid beers also use one of these two types of yeast.)
After the yeast is added at the correct temperature, the beer is usually kept at 15 to 20ºC (ale) or 10ºC (lager). The transformation of sugar into alcohol by yeast generates heat, and this process must be kept under strict control. A higher temperature with yeast for ale leads to a more active formation of aromatic organic compounds – esters.
Maturation
During the aging process, ales and lagers mature and acquire their final flavor, and the amount of fermentation byproducts decreases. Dry hops may also be carried out at this stage to achieve a more pronounced aroma. Greater complexity of flavor can be imparted through other methods, including barrel aging.
The cold storage of the beer for 30 days, known as lagering, determines the main difference between lager and ale: greater transparency and a different taste.
Bottling and carbonation
After the fermentation process is complete, the beer must be poured into kegs or bottles and carbonated, either naturally or by force. With forced carbonation the CO2 is pumped into the container at high pressure to saturate the drink with carbon dioxide. Forced carbonation is used more often because it speeds up the process and makes the beer even more transparent.
During the fermentation stage, “kreuzening” can also be used for carbonation. In addition, bottling or the addition of small quantities of sugar and yeast during bottling is also used for this purpose.