My wife made me a collection of hop extracts for flavoring beers. (she had already tried tea bags for infusing).
It only took a small amount to really pump up the aroma and flavor.
Here is her comments: "6 varietal extracts made with cold vodka so aroma and flavor are not destroyed and a mixed boiled bittering hops. Chinook, Columbus, Magnum, Amarillo, Cascade, Willamette and bittering hops. Just 2 or 3 drops and wow! Flavor abounds!"