Beer styles—ingredients: From which primary grain source is traditional Bock beer produced?

Introduction / Context:
Bock is a traditional German lager style known for higher original gravity, rich malt flavor, and smooth mouthfeel. Identifying the core grain source clarifies why Bock beers taste malty and display characteristic color and aroma.

Given Data / Assumptions:

• Bock is a beer style, not wine.
• Malt character is central to its profile.
• Color ranges from amber to deep brown depending on kilned/roasted malts.

Concept / Approach:
Classic Bock recipes rely on barley malt—often with a proportion of darker kilned or roasted malts to develop color and melanoidin-rich flavors. While adjuncts like rice or corn are used in some lager styles to lighten body, they are not the defining base of Bock. Wheat is central to Weissbier, not Bock. Grapes are used in winemaking, not beer.

Step-by-Step Solution:

Verification / Alternative check:
Style guidelines (for example, BJCP) emphasize malt richness from barley malts as the hallmark of Bock styles (Bock, Doppelbock, etc.).

Why Other Options Are Wrong:

Common Pitfalls:
Assuming all lagers share the same adjunct profile; Bock is malt-centric and not adjunct-driven.

Final Answer:
Roasted, germinated barley malt (malted barley).