Peroni Nastro Azzurro, the widely recognized Italian pale lager, is built upon a foundation of carefully selected plant-based ingredients. These botanical inputs contribute specific chemical components and structural properties that define the beer’s flavor and clarity. The primary plant materials—barley, maize, and hops—undergo precise transformations during the brewing process. Understanding the role of each ingredient provides insight into the beer’s distinctive, crisp profile.
The Primary Plant Base: Malted Barley
The structural backbone of the beer is malted barley, derived from the grain of the Hordeum vulgare plant. Barley is chosen because its endosperm contains high concentrations of starch, which is a complex carbohydrate stored in granules. This starch must be converted into simple sugars for the yeast to consume later in the process.
To prepare the grain, it undergoes malting, a controlled process of germination that activates dormant plant enzymes. The grain is steeped in water and allowed to sprout slightly, during which time it produces enzymes like amylase. The malting process is halted through drying before the starches are fully consumed, preserving the enzymatic power for the brewer to use. This preparation is paramount. Malted barley provides the majority of the fermentable material and the initial building blocks for the beer’s body and color.
Distinctive Grain Addition: Maize and Flavor Profile
Peroni Nastro Azzurro incorporates a substantial portion of an adjunct grain: a specific variety of Italian maize, known as “Nostrano dell’Isola.” This maize is added to the mash alongside the malted barley, often making up about a quarter of the grain bill. This addition introduces a high-starch, low-protein source into the brewing process.
Maize starches ferment cleanly and completely, reducing the overall protein content compared to 100% barley malt. Lower protein levels result in a lighter body and a paler, clearer liquid, as proteins can cause haze and contribute a heavier mouthfeel. The inclusion of this corn variety helps give the lager its characteristic dry, crisp, and refreshing finish. The clean fermentation profile ensures the final product is highly attenuated, meaning a greater percentage of available sugars are converted into alcohol.
The Biological Role of Hop Varieties
The female flowers of the hop plant, Humulus lupulus, are added to the boiling wort to provide bitterness, aroma, and stability. Hops contain a resinous substance called lupulin, which is rich in various compounds that define the beer’s flavor profile. The primary bittering agents are alpha acids, such as humulone, which are isomerized during the boil to become more soluble and intensely bitter.
Hops also contribute volatile essential oils and terpenes, which are responsible for the beer’s delicate floral and aromatic notes. Peroni Nastro Azzurro uses a blend of aromatic and bitter hops to achieve its balanced profile, with the oils providing subtle spice and flower fragrances. Beyond flavor, the hop acids possess mild antiseptic properties, acting as natural preservatives that inhibit the growth of spoilage bacteria, contributing to the beer’s shelf stability.
Enzymatic Transformation of Grains
The plant ingredients are linked to the liquid beer through the mashing process, where the enzymatic transformation of starches occurs. During the mash, the malted barley and maize are mixed with hot water, reactivating the amylase enzymes created during malting. These enzymes function as catalysts, targeting the complex starch chains within the grain endosperm.
Alpha and beta amylase enzymes work together to break down the starch into fermentable sugars, most notably maltose. Alpha amylase randomly cuts the long starch molecules into shorter fragments, while beta amylase systematically cleaves maltose from the ends of the chains. This conversion is temperature-dependent. Brewers carefully control the mash temperature to favor the production of either more fermentable sugars (for a dry beer) or more unfermentable dextrins (for a fuller-bodied beer), determining the final sugar content that the yeast will later convert into alcohol and carbon dioxide.