We homebrewers love our hops. Whether they blast our palates with citrus, fruit and bitterness or tempt our taste buds with flowers and subtlety, hops are the spice of our beers and of our lives. But few of us realize the hurdles that new hops must face before reaching our brewpots.
   
The explosion in interest for craft beers in the United States is fueling a search for new and interesting varieties. American beer lovers are enjoying new beers and beer styles that could only have been dreamed of just a decade or so ago. And that’s where our journey begins.
   
It takes about ten years to get a new hop variety ready for the commercial market in Washington state’s Yakima Valley — the most important hop growing region in the United States. When you buy hops to plant in your garden or yard, you’ll get a rhizome, which looks like a stick. It is a cutting from an existing plant and essentially a clone of that mother plant. That variety of hops can trace its lineage to a single seed that may have faced long odds when it was first covered with earth.
   
“The goal is to find a hop that’s going to yield well and have all those brewing qualities that brewers are looking for,” says Karl Vanevenhoven, director of operations for Yakima Chief, located in Sunnyside, Washington.
   
According to Vanevenhoven, hop breeding companies may start with 30,000 to 50,000 new varieties to evaluate in the search for new successful strains. These are hybrids of existing varieties, and they’re started from seeds that must be put through the paces before being put on the market.
   
The hop plants that you may have in your yard are female. Unless there is a rogue male hop plant nearby, the cones of the female plant will not bear seeds. However, the hop breeding companies keep male plants and are skilled at matchmaking between varieties.
   
Of those initial tens of thousands of plants grown from seed, 90% will be failed in the first one to two years. Among the characteristics breeders are looking for is yield. Will the plant produce enough product to be commercially viable? A hop with good flavor and aroma characteristics that doesn’t produce a sufficient amount of cones won’t be a good investment.
   
If the hop varieties make the cut within the first couple of years, they will be moved to a single hill full-sized commercial trellis for the next two years. At this stage, yield is still a question for full-sized production because the plant is getting much more special attention than it would in a field of several acres of its sisters.
   
At this point, the plants will be evaluated for their chemical composition. Alpha acids provide bitterness potential. Cohumulone levels may be an indication of how neutral or strong a hop’s character may be. Oil content will contribute to the aroma of the hop. Humulene is the oil described as “elegant,” while myrcene is said to give hops more “zing.”
   
At around year five, those plants that make the cut are expanded to several plants, and the breeders begin approaching commercial brewers to gauge interest in the new candidates. If there is no interest, the new hop varieties’ five-year mission is over, and their trek is at an end.
   
Vanevenhoven says those that show promise are distributed to several areas in the Yakima Valley, where they are tested for response to different climates and growing conditions. Once viability is confirmed, and brewer interest is solidified, the new hop variety can be released.
   
Of course, depending on availability, it may still be a matter of time before those hops make their way into our kettles at home. As we found out during the hop crisis, homebrewers are at the back of the line when it comes to buying hops. We’ll have to wait our turn until after commercial breweries take their share.
   
So, what are brewers looking for? Traditionally, commercial brewers divide hops into three categories: bittering, aroma and dual-purpose. Bittering hops have high alpha acid levels that allow brewers to brew big IPAs and other strongly bitter beers without having a relatively large amount of vegetation in the kettle. Aroma hops are better being added at the end of the boil, where their volatile characteristics won’t be stripped away by the heat. Some hop varieties straddle the fence and contribute wonderful flavors and aromas in the kettle and fermenter while still packing a decent punch of alpha acids.
   
You can find detailed characteristics of hop varieties on data sheets, easily found with a Google search for HopUnion, Yakima Chief, Hopsteiner,  Brewers Supply Group, New Zealand Hops or Hops from England. (All of the information available in 2009 is  also collected in BYO’s special issue Hop Lover’s Guide, available at most homebrew shops.) However, know that the levels of alpha acids and oils may shift from year to year, so you’ll have to keep that in mind while formulating recipes.
   
Let’s take a look at some recent varieties that have made the cut:

Citra
Over the past ten years, Sierra Nevada Brewing, of Chico, California, has been instrumental in promoting the development of new hop varieties. According to Sierra Nevada’s communications coordinator Bill Manley, the brewery guarantees hop breeders that they will purchase a certain acreage of new varieties. A couple of years ago, a new hop caught the attention of the brewers at Sierra Nevada.
   
“Citra really has something a little bit different,” says Manley. “It has those kind of bracing, bright notes, but a stronger flavor – more of a southeast Asia kind of mango mixed with the standard-issue citrus.”
   
The Sierra Nevada brewers chose Citra along with Magnum and Crystal as aroma hops in their Torpedo Extra IPA. The beer is brewed with the torpedo device — a stainless steel vessel designed to hold eight pounds of whole hop cones. Beer is run cold through the torpedo and back into the fermenter to maximize the tropical fruit notes. Citra has a myrcene level of 60–65% of the total oil, on par with many of the so-called “C” hops (including Cascade, Centennial, Chinook and Columbus), which may account for its strong flavor and aroma characteristics.
   
Citra is also a high alpha hop, with alpha acid percentages ranging from 11–13%, but Manley says it takes on a different character in the kettle. “If you use Citra as a bittering hop, it really has a very different flavor,” he says. “It becomes more ‘catty,’ I find, in the boil than it does as a late hop or straight aroma hop.”
   
Citra is a low-cohumulone hop, with 22-24% of the alpha acids being co-humulone.
   
Citra is growing rapidly in the marketplace. Manley says two years ago, when Sierra Nevada first used the hop, there were four acres planted. Now, he says 140 acres are dedicated to this variety. Look for Citra to be featured in January in a new Sierra Nevada beer called Hoptimum, which also employs several experimental hops that don’t even have names yet.
    
Sorachi Ace
In 1988, Sorachi Ace was bred in Japan by Sapporo Breweries from Brewer’s Gold, Saaz and male Japanese variety. It is a high alpha variety — 10–16% apha acids, low (~23%) co-humulone — but its citrus characteristics and unique lemon-like character also make it a good flavor and aroma hop as well.
   
Brooklyn Brewery, of Brooklyn, New York,  features the hop in a saison named for it: Sorachi Ace. Originally a part of the Brewmaster’s Reserve series, Sorachi Ace will be a year-round release beginning in February.
   
Brooklyn brewer Garrett Oliver decided to use Sorachi Ace as the only hop in its namesake. “The unique flavor of Sorachi Ace was bypassed by the big brewers, but we think it’s pretty cool,” Oliver says. “We ferment it with our special Belgian ale strain, and then add more Sorachi Ace hops post-fermentation. After the dry-hopping, the beer emerges with a bright spicy lemon zest aroma backed by a wonderfully clean malt flavor.”
   
If a lemony IPA sounds tasty to you, you might want to snag some Sorachi Ace while you can. According to Oliver, production of the hop is limited to a single farm in Oregon.

Ahtanum
If Sorachi Ace straddles the line between bittering and aroma, Ahtanum bridges the divide between American and English character – at least according to Mitch Steele, head brewer and production manager for Stone Brewing.
   
If you look at the HopUnion data sheet for Ahtanum, it says it is “quite similar to Cascade,” with Cascade and Amarillo as possible substitutions. That’s not how Steele sees it.
   
“It’s got some citrus character,” Steele says, “but I think it’s also got some of that English kind of earthiness character that I think is really nice.”
   
Ahtanum is the signature flavoring hop for Stone Pale Ale. It doesn’t pack much bittering bite, weighing in at only around 5.7–6.3% alpha acid, with 30–35% co-humulone (a bit lower than Cascade). In Stone’s Pale Ale, Columbus takes the bittering burden.
   
According to Steele, Stone’s brewmaster Steve Wagner chose Ahtanum in 1996 to contrast their inaugural beer with San Diego local favorite Sierra Nevada Pale Ale.
   
Steele says Ahtanum is a good substitute for British hops for homebrewers. “It’s not going to work real well in an IPA,” he says, “but if you want something that’s got some flavor balance and a nice unique character that’s not overpowering, it’s a great hop.”
   
By the way, Ahtanum’s pedigree is listed as open pollination, so Mother Nature gets partial credit for the success of this cross.

Palisade
Megan Parisi, lead brewer for Cambridge Brewing Company, in Massachusetts, paired Ahtanum with Palisade to feature in her Spring Training IPA. Being a spring seasonal beer, Parisi wanted to find hops that were reminiscent of the season. She made her selection after experimenting with several hop varieties.
   
“The Ahtanum are really super floral,” Parisi says, “but that kind of real essence of spring – fresh cut grass, fresh cut flowers. The Palisade is a little floral, but a little more grassy with a little bit of spice – almost a hint of the Tettnang kind of spice.”
   
Both hops are added to the boil equally in late hop additions for Spring Training. Parisi uses 1.5 lbs. of hops per barrel (the equivalent of 3.9 oz./110 g per 5 gallons/19 L), dry hopping with whole Ahtanum cones in the fermenter. A small bittering addition of Galena is added for balance.
   
With an alpha acid range of 5.5–9.5%, and a co-humulone level between Citra and Ahtanum, Parisi believes Palisade would be more versatile than Ahtanum in hopping beer styles other than IPAs.
   
“Anything where you’re looking for a little more alpha, a little more grass,” she says. “It’s not quite as distinctive.”
   
Simcoe
Simcoe has been around for a couple of years, and it has risen to be one of homebrewers’ new favorites. My first experience as a homebrewer with Simcoe involved a wheat beer that I wanted to be a showcase for the new generation of American hops. Paired with Amarillo at the end of the boil, the Simcoe brought a piney aroma to the grapefruit flavor of the Amarillo. An ounce of each at the end of the boil for the 5-gallon (19 L) batch did the trick well.
   
Added earlier in the boil for a double IPA, Simcoe showed off its ability to add a nice level of bitterness. Simcoe’s alpha acid level range is 12–14%, making it flexible for both hopping purposes. BYO Editor Chris Colby designed a double IPA for use in one of our Brew Your Own/Basic Brewing Radio Collaborative Experiments. His recipe called in an army of American hop stars: Magnum, Simcoe, Centennial, Cascade, and Amarillo, with additions throughout the boil period and Cascade for dry hopping. Colby says, “Simcoe’s piney flavor complements the American ‘C’ hops well. Plus, as a high-alpha, low-cohumulone (15–20%) variety, you can blend it with high co-humulone bittering hops to get the right amount of co-humulone ‘bite’ in your big IPAs.”

Summing Up
Just a few years ago, homebrewers were limited to a handful of traditional hop varieties, if they could find them at all. However, now craft brewers are driving the development of new varieties that challenge our expectations of beer character and styles. The only limit is our willingness to think outside traditional boundaries and play with our hops.
   
For the homebrewer, evaluation of new hop varieties can begin by tasting commercial examples that use the hops. For better information, experimentation is key. Choose a new variety that you haven’t played with, check the characteristics, and substitute it in your favorite pale ale or other hoppy beer style. Better yet, brew a single hop beer and taste it side by side with the same beer made from your favorite hop or hop blend. Taste critically and take good notes to guide your formulation of your next brew.    

    James Spencer, host of Basic Brewing Radio, thanks Ralph Woodall of HopUnion for contributing to this story.