The Ingredients of Beer
Water: Water comprises more than 90% of beer, so its origin and characteristics— ground, surface, treatment process—have an impact on a beer’s flavor.
Grains: A fermentable starch is one of the basic building blocks of beer and the primary determinant of its strength and flavor. Barley is the most common source, though some brewers use other malted and unmalted grains like wheat, rice, oats, corn and sorghum.
Hops: These are flowers of the hop vine used to balance the sweetness of the malt with a distinctive, slightly bitter taste; they also contribute to the floral and citrus flavor of the beer. Hops have an antibiotic effect that favors the activity of brewer’s yeast over other microorganisms, and their acidity acts as a preservative.
Yeast: This is a type of fungus that turns the sugars extracted from grains into alcohol. Brewers classify yeasts as top-fermenting and bottom-fermenting. Top-fermenting yeasts form a foam at the top of the wort tank, working their magic in warm temperatures. They can produce fruity, heavy, earthy ales. Bottom-fermenting yeasts settle at the bottom of the vat, working their magic in colder temperatures. These yeasts, typically used to produce lagers, ferment more sugars, leaving a crisp taste.