Water

The most prevalent ingredient in beer, and perhaps the most overlooked by consumers in terms of its impact on a beer’s flavor, water plays a significant role in the shaping of a great beer. In general, great tasting water can produce great tasting beer, but a conscientious brewer must carefully consider the pH and mineral content of their water source as it pertains to the style of beer (s)he is trying to create. For example, soft water is most notably used in traditional Bohemian Pilsner, while mineral rich (hard) water is more commonly used to brew English-style IPA

Malted Barley

A primary source of color, flavor, and body, malted barley is commonly considered the heart of a finished beer. Before it can be used for brewing, barley must first be malted, whereby it is steeped in water to induce germination, then rapidly kiln dried. Malted barley can be roasted to varying degrees to influence beer flavor and color. Pale malts offer delicate bread-like flavor to beer, lightly caramelized malts contribute subtle toffee notes and amber coloring to beer, while deeply roasted malts offer a chocolate or coffee characteristic and coloring to beer

Hops

The spice of beer, hop flowers provide aroma, bitterness, and preservative properties to beer. Dozens of varieties of hops available to brewers offer aroma characteristics that range from floral to citrus to earth to pine. Hops added at the start of the boil during brewing contribute primarily to the bitter flavor of beer, while hops added at the conclusion of the boil contribute aroma to a beer. Hop 'bines' thrive in cooler climates and grow up to 25 feet tall in a single season. Brewers use hop oil, pelletized hops, whole leaf dried hops, and even freshly harvested hop flowers.

Yeast

Although not visible to the naked eye, microscopic yeast cells are responsible for converting fermentable sugars into alcohol and carbon dioxide, thereby creating beer. Dramatic advancements in technology and yeast management over the past decade enable breweries of all sizes to procure a huge variety of style-specific yeast strains. Yeast is often thought of as the soul of a beer, as it dramatically shapes the finished product. Different ale yeast strains are noted for providing fruity esters and spicy phenols to beer, while wild yeast strains provide a tart quality.