Which component primarily contributes to the smell of beer?

The primary component that contributes to the smell of beer is hops. Hops contain essential oils and alpha acids that are crucial in imparting aromatic qualities to beer. These oils include myrcene, humulene, and caryophyllene, which create a diverse range of aromas such as floral, citrus, pine, and spicy characteristics.

When added during the brewing process, particularly during the boiling stage or in dry hopping (adding hops post-fermentation), these aromatic compounds are released and dissolve into the beer, significantly influencing its aroma profile. While other components such as malt and yeast do contribute to the overall aroma of beer, it is primarily the hops that provide the distinct and often prominent scents that craft beer enthusiasts seek out.

Water does not contribute any smell itself, as it is essentially a neutral component in terms of aroma, while malt can impart some sweetness or bready notes but does not dominate the aroma in the same way hops do. Yeast can produce some esters and phenolics that affect aroma, especially in certain styles, but in terms of the overall contribution, hops are the definitive source for the best-known beer aromas.