Humulus Lupulus (hops) are the flowering cone of a perennial vining plant and a cousin of the cannabis variety (sorry no THC in this stuff) that typically thrives in climates similar to the ones that grapes do. Hop plants are dioecious, meaning the males and females flower on separate plants -- and the female cones are used in the brewing process. Hops are the age old seasoning of the beer, the liquid gargoyles who ward-off spoilage from wild bacteria and bringers of balance to sweet malts. They also lend a hand in head retention, help to clear beer (acting as a natural filter) and please the palate by imparting their unique characters and flavours. Basically, hops put the "bitter" in beer.