What is the main reason for adding hops during the last stages of boiling?

The primary reason for adding hops during the last stages of boiling is to maximize the retention of hop oils. When hops are added later in the boil, especially in the final 5-15 minutes, the temperature of the wort helps extract essential oils from the hops without losing them to evaporation. These hop oils contribute significantly to the aroma and flavor profile of the finished beer, which is especially important for styles that emphasize hop character, such as IPAs.

In contrast, adding hops earlier in the boil is primarily associated with bittering due to the longer exposure to heat, which enables the conversion of alpha acids into iso-alpha acids that impart bitterness. However, this process can reduce the aromatic qualities that are best preserved through later additions. Therefore, for brewers looking to achieve a flavorful and aromatic beer, late hopping is essential for capturing the aromatic qualities of hops, rather than just increasing bitterness or addressing issues like sediment or carbonation.