It is fresh-hop season up here in the Northwest, the region in the country where the vast majority of hops are grown. We happen to live here, and some of us even attempt to grow our own...here is my first year attempt at some Chinook and Centennial varieties.
Typically hops are harvested,de-hydrated/dried and packaged for use for the upcoming year. A brief window exists each fall where brewers get fresh, many going vine-to-kettle in a matter of hours and fresh hops impart really unique and amazing flavors in their brews. It's hard to describe the taste difference, the bitterness seems to be less harsh, the flavors more pronounced.
Most of the country will not get to experience this glory, as fresh hopped beers need to be consumed quickly - they very rarely get bottled. Do yourself a favor if you live in the NW and attend a fresh-hop festival like this one in Hood River.
Ex Novo will be brewing up a fresh-hop Amber Ale on Wednesday as part of a fund-raising benefit, using what hops I can gather from my yard and my neighbor's Cascade bounty. Stop by and put your nose in some green goodness.