St. Louis - Home of American Brewing

How Beer is Made

Courtesy Schlafly Beer

Beer is made from four basic ingredients: water, malt, hops and yeast.

Water makes up the largest percentage of beer, and because the minerals and chemicals in water affect the flavor and character of the beer, it’s important to have the proper chemical make-up in the brewing water.

Malt in beer brewing typically refers to barley malt, although smaller proportions of other malts like wheat or rye may be used in conjunction with barley malt. Malt gives beer its sweetness and body, or “mouthfeel.”

Malt is also the term for grain that has been steeped in water until it begins to sprout, allowing enzymes to form in the kernels. It’s then heated in order to dry the grain and to stop the sprouting. The length of time and the temperature at which the grain is roasted or “kilned” will determine its color and flavor, so creating a recipe with different malts will, in turn, determine the color and flavor of the beer. The malting process is done by professional “maltsters” and the malt is then sold to breweries.

The amount of malt used is proportionate to the alcohol strength of the beer. Color does not determine how strong or heavy a beer will be, although the majority of light-colored beers are lighter in body and alcohol than dark beers. Many dark-colored beers, for instance brown ales, are very mild and easy to drink.

Hops give beer its bitterness, which is necessary to balance the sweetness of the malt. Different hop varieties give different flavors and, if the brewer chooses, different aromas. The hops also act as a preservative in beer.

Yeast ferments the sugar from malt into alcohol and produces carbon dioxide, which can naturally carbonate the beer. There are many varieties of both ale and lager yeast strains, with some contributing little noticeable character to the beer, while others contribute a lot.

Beer can be classified into two categories – ales and lagers – and is determined by the type of yeast used.

Ale yeasts ferment at higher temperatures, which produce a fruity or “estery” character. Ales are typically referred to as “top fermented,” which means the yeast generally rises to the top during the fermentation process.

Lager yeasts ferment at cooler temperatures, producing a crisp, clean character with little or no fruitiness. Lagers are typically referred to as “bottom fermented,” which means that the yeast settles at the bottom of the tank during fermentation. Not all ale yeasts rise to the top, however, and not all lager yeasts settle to the bottom, so these descriptions don’t define all ale and lager yeast strains.

Before the brewing begins, the malt and grains for the recipe, known as “grist,” are milled in order to crack the husk of the kernel so that the starch is exposed. The grist is then mixed with hot water to form the “mash,” where the enzymes formed during malting convert the grain’s starches into sugars. The sweet liquid, called “wort,” is then drawn off the grain bed and hot water is sprayed over the mash in order to extract more sweet wort from the grains.

The wort is then collected into the kettle to boil, which clarifies it by coagulating protein solids that may have a negative effect on the finished product. It also concentrates the wort through evaporation. This is the process where hops are introduced. For more bitterness, hops are added early in the boil in order to extract more bitter resins. To get hop aroma, hops are added at the end of the boil to reduce the aromatics from boiling out with the steam.

The wort must be cooled to the proper fermentation temperature for the yeast being used. Sterile air is dissolved into the wort so the yeast will have the oxygen it requires to grow and ferment the sugars into alcohol. Ale fermentation typically occurs at temperatures between 60 and 70 degrees Fahrenheit, and the sugars are consumed by the yeast in around three to five days. The process could take longer, depending on the amount of sugar in the wort. The “green” beer is then chilled to near freezing temperature and allowed to “condition” for up to two weeks or more.

Lager fermentation typically occurs between 40 and 55 degrees Fahrenheit, with the sugars being consumed by the yeast in five to eight days. As with ales, the process can take longer, depending on the amount of sugar in the wort. The temperature is then dropped to near freezing and the beer is stored, or “lagered,” for anywhere from several weeks to several months.

Filtration removes yeast and other solids, such as proteins, that are suspended in the beer. This produces a “bright” rather than hazy beer, and it may strip the beer of color, body and flavor. Depending on the style of beer and the preferences of the brewers and their consumers, a beer may or may not be filtered before serving or packaging.

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