What is the significance of adding hops later in the boil?

Adding hops later in the boil primarily enhances the flavor and aroma of the beer. When hops are added at the beginning of the boil, the intense heat causes many of the volatile aromatic compounds to evaporate, diminishing their presence in the final beer. Conversely, when hops are added toward the end of the boil or during whirlpooling, these aromatic oils are preserved, leading to more pronounced hop flavors and aromas. This technique is especially important in styles that prioritize hop character, such as IPAs and pale ales, where the impact of the hops is critical to the beer's overall sensory experience.

While hops do contribute to beer stability and can affect fermentation in various ways, these aspects are more relevant to the timing and types of hops used throughout the brewing process rather than the effects seen from late additions. The cost of hops is generally not influenced by the timing of their addition in the boil. Therefore, the enhancement of flavor and aroma is the most significant reason for adding hops later in the brewing process.