Brewing Theory 101

Most beer drinkers know that quality beer is made from four ingredients: malt, hops, yeast and water. Here's a look at what each contributes to beer.

Malt

Malt contributes flavor, color and body to beer. Malt flavor is generally sweet, and, depending upon the type of malt used, may be toasty, caramelly, nutty, chocolate-like and even acrid-ash-like. Virtually all of the color of beer comes from malt.

"Malt" is short for malted barley, the most fundamental ingredient of beer. Barley is a cereal grain, similar to wheat, rice or oats. Beer has been made from each of these grains at one time, but barley is the grain best suited to beer making.

To make malt from raw barley, the grain is allowed to germinate. A small barley plant begins to grow inside the grain and rootlets sprout on the outside. But before this process gets very far, the grain is dried and toasted. Depending upon the extent of toasting, different colors of malt can be made for use by the brewer.

Malting makes the contents of barley much easier to use in making beer. During the phase of brewing known as mashing, the starch inside the malt is naturally converted to sugar and dissolved in hot water. This process extracts 50 to 80 percent of the weight of the malt into the beer. The resulting sugar-infused hot water -- known as wort -- forms the base for every beer.

The malt extracts used in homebrew recipes are simply a concentrated form of wort. Most of the water has been evaporated so that the sugars are present in very high levels. When the extract is dissolved in hot water, it gives you a wort that is very similar to that produced in a brewery.

Hops

Hops contribute bitterness, flavor and aroma to beer. They also reduce the potential for bacterial infection and contribute other positive chemical properties.

Technically hops are flowers, but they look more like small green pine cones. There are dozens of different hop varieties and each contributes a slightly different character to beer. The flavors and aromas associated with hops include flowery, perfumy, spicy, herbal, resinous, citrusy and grassy characteristics.

The use of hops in beer is a bit like making tea. We soak (or boil) hops in hot wort at various times, but only a small portion of the hop weight is extracted. Only five to 15 percent of the hop actually gets used in beer.

Hop bitterness is used to balance the sweetness of malt. Hops produce the most bitter character when boiled for longer periods, generally 45 to 90 minutes.

Hop flavors are produced when the hops are boiled for shorter periods of time, generally 10 to 30 minutes. Hop aromas come from even shorter exposures -- 1 to 5 minutes of boiling or steeping in the hot wort after the boil. Sometimes hops are added to fermented beer to provide a unique aroma character. This practice is known as "dry hopping."

Basic homebrew kits such as those featured in Your First Batch and Your Second Batch, already include hop bitterness. Unhopped extracts are also made and they form the base of our Third Recipe.

Yeast

Although brewers take the credit, it is yeast that actually makes the beer. These small, single celled organisms eat sugar and excrete alcohol, carbon dioxide and important beer flavor compounds.

The world of brewerâs yeast is generally divided into two groups: one for ales and one for lagers.

Ale yeast ferment best close to room temperature (65-70 deg F). They work quickly, and generally finish the main fermentation in three to five days. These yeasts characteristically contribute fruity flavors to the finished beer: subtle apple, banana, pear and even peach notes may be found.

Lager yeast ferment best at cooler temperatures, generally 50-55 deg F. They work more slowly and may take up to three weeks to finish primary fermentation. After this, the yeast is kept in contact with the beer for a substantial period of cold fermentation known as "lagering." During this phase, the beer acquires a very smooth and pure character. Lagers typically lack the fruity features found in ales.

Among these two types of beer yeast, many different strains may be found. Each produces slightly different effects in beer. As a result, brewers view yeast selection as an important step in recipe formulation.

The yeast included in most homebrew kits is a general-purpose ale yeast. These are packaged in a dry form for easy transportation and use. More advanced homebrewers use "liquid yeast" pouches which offer a greater selection of flavor effects.

Water

Despite the amount of advertising devoted to the subject, "pure" water is not ideal for making most styles of beer. Water naturally contains various minerals such as calcium, magnesium, choride, sulfate and carbonate. Each of these contributes a subtle, and often postive, flavor effect to beer.

Most famous brewing centers, including Munich, Dortmund, Burton and Dublin, have relatively hard water supplies. Their beer styles have been formulated to capitalize on the character of the water to make a tasty beer.

As a homebrewer, it will be a good while before you need to worry much about water chemistry. One thing you donât want to do is to start using distilled water in your beers. (Distilled water lacks many trace elements needed for proper yeast growth.) If you want to do something that will improve the flavor of all your beers, install a carbon filter as discussed in Basic Equipment.