What is Brewing?
Brewing is the process used to produce beer or any other alcoholic beverage. Essentially, it involves soaking barley (the source of starch) in water and allowing the mixture to ferment. Yeast is added to expedite fermentation and convert sugar into alcohol. In some cases, millet and sorghum are used as alternative sources of starch. The brewer must carefully adjust the process to achieve the desired results in the final stages of brewing. Below is a detailed overview of the entire process, which will help beer enthusiasts understand how brewing works.
1. Milling
Milling prepares the source of starch for brewing. At this stage, the brewer crushes the malted barley or other brewing grains to expose the starchy part of the grain that can be converted into fermentable sugars.
The brewer must avoid crushing the grain too much, as it can damage the husk, which serves as a natural filter bed for the brew. On the other hand, if the crush is too coarse, the brewer may not extract enough starch from the grain.
2. Mashing
After crushing the grain, it is placed into a mash tun, an insulated vessel that facilitates the mashing process. The crushed brew grain is mixed with hot water at a specific temperature to activate enzymes in the barley, which convert starch into sugar. The key enzymes in malted barley are alpha-amylase and beta-amylase.
Each enzyme operates within a specific temperature range. Therefore, the brewer carefully regulates the temperature to ensure optimal enzyme activity. High temperatures can denature the enzymes, while low temperatures can deactivate them.
Regulating the temperature in the mash tun also determines the type of sugar produced. For example, raising the temperature to a range of 149 to 153 degrees Fahrenheit activates the alpha enzymes, resulting in a sweet-tasting brew. Lowering the temperature to 126 to 144 degrees Fahrenheit activates the beta enzymes, producing highly fermented sugar and a dry beer. The mashing process typically lasts one hour, after which the brewer stops it by raising the temperature above 200 degrees Fahrenheit.
3. Lautering
Lautering is the process of separating the solid mash from the sweet liquid paste known as wort. The mash is drained into a Lauter tun with a false bottom, allowing the fermentable liquid to be separated from the solid mash. Hot water may be added to extract any remaining sugars in the grain mash. Care must be taken not to add too much water, as it may spoil the bitter tannins in the sweet and sticky fermentable liquid.
4. The Boiling Process
Once the sweet and sticky fermentable liquid is separated from the solid mass, it is transferred to a large brew kettle for boiling, typically lasting one to two hours. The brewing kettle has double walls with a gap for steam circulation, providing even and vigorous heating. The liquid is held in this tank for about 90 minutes.
During the boiling process, the brewer adds hops to the wort, giving it a bitter taste. Hops are typically added near the end of the boil but can also be added 15 minutes before the end. In addition to flavor and aroma, the boiling process sterilizes the mixture.
After boiling, the brew is transferred to a whirlpool chamber, where remaining hop matter, coagulated matter, and other liquids are filtered out. The brew is then rapidly cooled down.
5. Fermentation
The cooled and filtered brew is transferred to a fermentation chamber, also known as a fermenter, where yeast is added. Usually made of steel, this large chamber allows yeast to convert fermentable sugars into ethyl alcohol and carbon dioxide gas. The brew is left to ferment at a constant temperature of 68°F for about two weeks.
If the brewer intends to make a lager, the temperature is maintained at 48°F, prolonging the fermentation process to over six weeks. At this stage, the brewer decides whether to make ales or lagers. Ale yeast is used for ale production, while lager yeast is used for lager production.
Temperature control is crucial during fermentation, as it generates a significant amount of heat. When fermentation is complete, the yeast settles at the bottom of the tank and can be removed. The brew is then cooled to 32°F to eliminate any remaining yeast and protein residues.
6. Conditioning and Packaging
In this step, the brew is pumped into a bright beer tank. As it is the final stage of brewing, the brewer ensures that the product meets commercial standards. This may involve mechanical filtration and the addition of carbon dioxide to achieve the desired level of carbonation. Once the brew is confirmed to have the correct flavor, free from residue, and meets commercial standards, it is packaged in sealed bottles, cans, or kegs. The brew is now ready for the market.
