In the Spirit: Beer 101

Beer is a fermented beverage made essentially from four ingredients - water, cereal grains, hops and yeast. It is one of the oldest beverages produced by humans and some suggest that communal, agrarian societies were established, in part, to cultivate cereal grains for beer production.

Historically, many agree that it was likely an accidental discovery. It is, however, no accident that beer (and other fermented beverages) have played an important role in the development of modern societies, due to the very nature of it being "nutritious" and safe to consume. Though it might not have always tasted good, it wouldn't kill you. It has evolved from a rudimentary staple, produced with little understanding of the science behind it, into an intricate, refined beverage that has come to identify individuals, as well as geographical regions.

Let's look at the four main ingredients:

WATER

The chemical and physical properties of water are truly impressive. It is so ubiquitous, though, that we rarely give it much thought. As it applies to beer, water is the largest ingredient (90 plus percent) and is both a physical transport system and a supplier for the chemistry that allows beer production to occur. Water provides hydration, conveys heat and provides ions necessary for chemical reactions to take place. Most beer styles today were established in regions with a specific water chemistry that greatly influenced its development.

CEREAL GRAINS

Cereal grains are seeds that contain, among other things, the embryo, an initial food source to germinate the embryo and enzymes to regulate the chemistry that allows the seed to grow into a plant. Barley is the most widely used cereal grain in brewing and when harvested. It must undergo a malting process to make it usable in the modern brewing.

Growing plants is not the brewer's focus, so the embryo is unimportant. The embryos' initial food source, however, is vital because it is comprised of the enzymes necessary to break down the accompanying carbohydrates into simple sugars. Malting employs the addition of water, at specific temperatures, to initiate germination and to break down those carbohydrates. It is at this point dried and then packaged and ready to be used in the brew process.

HOPS

The flower of a perennial vine harvested and processed in the fall, hops are the "spice" of beer. The science involving hops is vast, but their general items of importance for brewing are alpha acids and essential oils. Alpha acids provide bitterness to beer. Heat is used to convert alpha acids in to a water-soluble form, which allows it to be carried throughout the brewing process and be a factor in the finished beer. Frequently known as bittering hops, they are added during the boil to the brew kettle to allow the conversion. Essential oils are a volatile hop component that will not survive the high heat conditions in the brew kettle. These compounds are also water-soluble and provide flavor and aroma to beer.

YEAST

Yeast is a single-cell organism capable of metabolizing sugars into carbon dioxide and alcohol. Considered one of the earliest domesticated organisms, yeasts that produced good beer were reused from batch to batch over time. While there are hundreds of types of yeasts, only a select few are used in brewing, generally. Different yeasts will produce various flavors and aromas - in conjunction with carbon dioxide and alcohol - unique to each beer style.

BASIC BEER STYLES

ALES

Ales are historically the oldest type of beers pro-duced. Ale yeasts are often called "top fermenting" strains, referring to a characteristic in yeasts that allows a portion to migrate to the top of the fermentation vessel, creating a frothy layer of yeast and beer by-products. Ale fermentations are generally conducted at temperatures that are warmer than lagers and produce by comparison, more elevated levels of esters, phenols and organic compounds, which produce fruity, mineral and medicinal characteristics.

Brewing is a European tradition, with virtually all historic continental brewing centers known for their individual ale styles. Germany is known for Weizens, Alts and Kolsch beers. Great Britain is famous for IPAs, along with Stout and Bitters. Belgium is widely regarded as possessing the most eclectic beers styles, ranging from sour Lambics and earthy Saisons to Trappist Monastic Ales.

LAGERS

Widespread lager production was born out of the Industrial Revolution's advances in electric power and, more specifically, refrigeration technologies. Continental Europe, most notably Germany, brew these types of clean-flavored beers, with lower levels of esters, phenols and organic compounds. Lagers are fermented with yeast strains at lower temperatures than ales and typically undergo an extended cold conditioning period known as lagering. As in ales, yeast can impact the flavor and aroma profiles of lagers, its malt, hop and water chemistry characteristics are showcased instead. There are a great variety of lager styles, ranging from light to dark, malty to hoppy and low to high alcohol content, with wonderful examples of their styles.

THE BREWING PROCESS

Brewing of beer can be broken down into two main components: The "hot side" and the "cold side." The "hot side" occurs in the brewhouse and involves the addition of heat to move the brewing process along. The "cold side"involves the removal of heat and takes place in the "cellar" to complete the process.

The brewing process is initiated by using three of the four main ingredients: Water, cereal grains/malt and hops. Malted barley and cereal grains must be cracked open using a rotary mill to expose the carbohydrates and enzymes inside the whole grain. This milled grain (grist) is added, along with hot water, to a mash tun vessel, to form a porridge-like consistency mash.

The malting process serves to modify the cereal grains from their harvested raw state, and is completed during this mashing stage to reduce the remainder of carbohydrates in the malt to simple sugars. Simple sugars that will be metabolized by the yeast later in the brewing process. Over a two-hour period, the grist is rinsed with additional hot water and the entire contents from this process are deposited into a brew kettle.

When the transfer is complete and the brew kettle is full, the wort is boiled for 60 to 90 minutes. Important chemical reactions occur during this process; the sterilization of the wort and the conversion of hop alpha acids from non-water soluble to a water soluble state, which will create bitterness in the final product.

It is important to note, that, just as we separated the liquid wort from the solid grain residue in the mash tun, almost every step in brewing involves a clarification component and the activities in the brew kettle are no different. At the end of the boil, there is a short rest period to allow coagulated proteins and unusable hop matter to come out of suspension from the boiled wort and left behind in the brew kettle, as the boiled wort is removed and transferred to a fermentation vessel.

FERMENTATION/MATURATION

When the boiled wort is ready to leave the brew kettle, it is transferred to a fermentation vessel, to which yeast is added. During this transfer, the wort is passed through a heat exchanger, which cools it to a temperature that allows the yeast to live and complete the fermentation process, producing carbon dioxide, alcohol flavors and aromas associated with specific beer styles. After fermentation, the maturation process takes place, the dry-hopping phase (if relevant for the beer style), during which the temperature is dropped to help clarify and stabilize the beer. So, it can then be further processed to become a consumable product.

As the temperature drops, yeast, additional proteins and solids drop out of the liquids' suspension and the beer becomes clearer. Finally, many beers are then mechanically filtered at cold temperatures for further clarification. At this point, they are transferred to a final tank before being dispensed or packaged into a keg. Maturation can last up to a week or more, depending on the beer style.

FINAL PROCESSING/DISPENSING

As mentioned above, as beer is again transferred from a fermenter to a serving/packaging tank, it may be filtered to remove any remaining yeast and undesirable proteins and solids that can inhibit clarity and long-term stability. At this point, the process is nearly finished and all that remains is to insure carbonation and temperatures are at the desirable levels. Additional carbonation in the form of carbon dioxide or mixed gas (a blend of carbon dioxide and nitrogen) can be introduced to the beer, making the beer ready to serve or package.