Humulus lupulus, or hops, provides beer with its flavor and bitterness. The type of hops used determines the flavor profile of the beer, with hoppy India Pale Ales offering a good profile of the range of flavors available from Humulus lupulus. True home brewers will want to grow their own hops; to do so, they'll need to order hops plants, which are sold as rhizomes. While hops plants have folk medicine uses as a sedative and poultice, the only true commercial use for this plant is in the brewing industry.
Research different types of hops at Beer Advocate's Hops Guide, which lists commonly used hops and describes their flavor profile and the type of beers they are used in (see Resources). If you're buying hops plants to brew your own beer, choose a hop that complements the type of beer you like to brew and drink. Chinook is used for American pale ales, Golding for English ales and Saaz for pilsners.
Locate brewing stores near you using the telephone directory. Call to determine whether the brewing store sells hops plants; many local brew stores sell hop rhizomes in the spring. If the store sells (or plans to order) hop plants, determine what varieties they sell and whether you need to pre-order plants. Make necessary arrangements to buy hops through your local brewing store.
Order hops rhizomes through an online retailer in the spring if you cannot locate brewing stores near you, if the stores do not plan to sell hops plants or if you cannot locate the type of hops you wish to grow. Since hops are a specialty plant, they're only available in the springtime.