In addition to being a fine excuse to drink German lager, in the beer world, October is hophead Christmas. Every year more and more breweries produce "wet hopped" beers using hops that have not been dried in a kiln to preserve them. (You'll also hear the terms "fresh hopped" and "harvest," which—with the exception of some semantic beer geek controversy—are generally considered synonymous.) When tasted fresh, these beers pack an extra-special hop punch and are coveted by many.
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With all due respect to a proper, hesitantly spiced pumpkin ale, fresh (or "wet") hop beers are my harvest beers of choice. Fresh hops have a damp, almost-still-alive character that's lost when the hop cones are dried and stored, and I've yet to see their flavor reproduced another way. When brewing these beers, there's often no more than a matter of hours between the time the hops are picked and when they're added to the brew kettle.
Once a year when hops are ready to be pulled from the vine, some brewers celebrate the season by heading out to local farms to harvest hops fresh. Once gathered, the hops need to be added to the brewing kettle as quickly as possible—the delicate flowers spoil rapidly, especially if exposed to heat.