To put it simply, terpenes do not survive the brewing process- but these compounds do. Each compound has a distinct aroma and flavor characteristic. For example linolool smells like pledge cleaner, fruit loops. These are the compounds you are identifying when you smell a hop, however if you use the hop at the wrong time of the brewing process, you can eliminate the characteristics you were looking for!

The more a variety has of a compound, the more that will survive the brewing process. It’s that easy. For example, Chinook has a lot of 3MH, so this can be used in whirlpool or active fermentation and some 3MH will still survive. However, if you do the same with Cascade, you’ll likely lose it all. So you would use Cascade on the cold side or post-fermentation dry hop.