From grain to kettle to bottle to glass let's take a trip through the brewing process.
Ingredients: Water
Of the 4 main ingredients, water is largest contributor and may account for up to 97% of the total beer. The mineral content of water may greatly affect the final beer's flavor and perception.
Ingredients: Malt
Malted grains provide fermentable sugars in addition to body, aroma, color, and flavor to the finished beer.
Ingredients: Hops
Hops are green, cone-shaped flowers of the hop plant. They provide aroma and flavor to beer in addition to acting as a stabilizing agent and balance to sweet malt flavors.
Ingredients: Yeast
Brewers pick from many different yeast strains, each of which will produce a slightly different character in the finished beer.
Barley, a grain similar to wheat, serves as the basis for most beers. Cereals, such as corn or rice, may also be used as 'adjunct' ingredients in addition to grain. Before barley, or other grains, may be used it must first be 'malted'.
The malting process begins with the maltster soaking barley in water to awaken the tiny proto-plant inside each barleycorn, allowing it to sprout, or germinate. Upon the first sign of germination, the maltster will immediately kiln the malt to stop the germination process. The process of germination activates enzymes that start the conversion of starches inside the kernel into simple sugars, primarily maltose. Maltsters may roast malted grains to varying degrees producing darker colors and flavors that may vary from biscuitlike to burnt.
Mashing & Brewing
Brewers may combine water, hops and malt in many different combinations to produce many different types and flavors of beer.
First the brewer combines the malt, and other cereals and grains, with hot water to produce a mash. This step occurs in the mash tun. Mashing allows natural enzymes in the malt to break down starch in the grain into simple sugars. Mashing yields an amber, sugar-filled liquid known as wort.
Then, the brewer will separate grain husks from the sugar-filled wort. This process is called lautering and occurs in the lauter tun. A process called sparging will also occur during this step. Sparging is the process of spraying the grain bed with water to extract as much of the fermentable sugars as possible.
Next, the brewer boils the wort for 60 to 90 minutes. Hops are added at various times during the boil producing different characteristics such as bitterness, flavor and aroma. Sterilization of the wort, stopping of the enzymatic process, and concentration of the wort also occur during the boil.
Fermenting & Conditioning
At the end of the boil the solid hop debris, known as trub, is removed from the liquid wort. Many modern breweries complete this step in a vessel known as a whirlpool.
The hot wort must be cooled as quickly as possible after the boil to fermentation temperatures. Many breweries complete this step through a plate heat exchanger that runs hot wort next to cold water running next to each other in alternating plates.
The cooled wort is then transferred to a fermenter. Here yeast is added. The yeast strain will dictate the exact time and temperature of fermentation, but most do best under one of two general programs. Lagers ferment at 50 to 55 F for 10 to 14 days, and then cold-condition, or lager, for 2 to 8 weeks at 35 to 40 F. By contrast, ales usually ferment at 65 to 70 F and are generally ready for consumption within 2 weeks.
Prior to bottling, a typical commercial ale or lager will undergo some form of stabilization to extend its shelf life. The two primary forms of stabilization are sterile filtration, in which the beer is passed through a microporous filter that will not let through any solids larger than 0.5 microns; and pasteurization, whereby the beer is heated briefly to kill any microbial bacteria.
Both approaches are widely used, though a number of brewers have noted that sterile filtration strips some hop flavors from their ales. A third, traditional option for preparing a beer for its journey in a bottle to your glass is "bottle conditioning". An unpasteurized beer bottled with its yeast will not age in the manner of a conventionally processed beer. With age, bottle-conditioned beers develop a rounded, smoother mouthfeel, and over the course of years, often take on winey, vinous flavors.
Bottle conditioning is an economical means for small-scale craft brewers to bottle ales without the need for costly pasteurization or filtration equipment. How long one cellars bottle-conditioned beers is a matter of personal taste and will also depend on the specific character of the beer in question.