Flower to the People: OSU Empowers Hop Sensory Panel

Hood River, Or. Oregon State's Hop Docs wanted feedback from Pacific Northwest brewers on building a new aroma hop and it sounds like they got an earful.

The consensus? Dial down the alpha, jack up the oils, and add something "tropical" to our flavor arsenal beyond the all-pervasive citrus bomb.

In it's mission to breed new aroma hops, Oregon State pulled together a panel of seasoned craft brewers, predominantly from Oregon, to evaluate a series of single hop brews. The format was simple:

• Create a sensory neutral environment .


• Present an experienced panel with six (6) single hop brews, plus a series of dry hopped brews.


• Ask each to fill out a confidential form that best describes the primary hop aroma (viz., floral, fruity, tropical, spicy) and flavor (viz., cirtrus, herbal, grassy, woody, sulfury, cheesy). For each rubric, the panel was asked to further define secondary descriptors, for example, my personal favorites: rose, apricot, mango, anise, sagebrush and not-so-favorites like sweaty, garlicky, leathery and rabbit urine-ish.


• And, finally, after each pair of test brews, open up the panel to a robust but sincere discussion.

The hop sensory panel is the first step in a novel two-part strategy designed by OSU professors Tom Shellhammer (the fermenter/hop chemist) and Shaun Townsend (the geneticist/breeder) in their science-driven quest to breed new aroma hops. Tom and Shaun have been collaborating since January 2010 in their noble mission, pursuant to a $1 million grant from Indie Hops.

The panel was convened in conjunction with the annual meeting of the Pacific Division of the Master Brewers Association (MBAA).

Help Us, Help You

The sensory panels using trained brewers, explained Dr. Shellhammer, is critical in providing clear guidance to Dr. Townsend, who will be selecting hop candidates for crosses in the hope of amplifying known or new desirable characteristics.

"We're looking for consensus," said an optimistic Dr. Townsend, whose mind seemed to be spinning with ideas after the panel. "Early in the breeding process, breeders generally work with little feedback from brewers and chemists. This is an important first step in selecting genotypes that can lead to new cultivars that express the profile sought by brewers. Having the end-product users involved at the front end of the breeding process eliminates a lot of the guesswork and gives me a clear set of goals."

Dr. Shellhammer was equally pleased. "The brewers were excited about being asked to participate in the process. Their candid and honest evaluations will help us narrow down the target characteristics. In the end, we're looking to develop alternatives to the current menu of commercially available hops that will endure the test of time."

The next step is for Dr. Shellhammer to analyze the data for patterns. Over the next few years, Dr. Shellhammer will be conducting at least six sensory panels. He is in early discussions with the San Diego Brewers Guild to hold a second hop sensory panel in early November of 2010.

More Tongues and Noses, More Data, Better Science

Several of the brewer panelists agreed that the research effort was both valuable and long overdue. One brewer told me that it was "just nice to be included. Instead of a few brewers pursuing their own agenda behind a veil of secrecy, it was great for OSU to open up the discussion among a diverse group of brewers. In the end, everyone benefits from innovation." To preserve the objectivity of the effort, and to avoid any hasty conclusions, OSU is keeping confidential the identity of the hop cultivars that were evaluated by the panel.

Another area of research of keen interest to the brewers was the optimal harvest date of aroma hops. As part of the Indie Hops grant, OSU will be conducting a pilot study on the correlation between harvest date and oil content in fresh cones. The brewers did not venture to say which specific oils they were interested in seeing more of. For now, their uncomplicated message is less alpha, more total oils. The panel also raised the concern that the craving for super alphas has led to a proliferation of harshly bitter concoctions that tend to blow up the tongue like a wet sponge.

The road to new and useful cultivars is long, narrow and mostly uphill into a headwind. There are no shortcuts -- no magical bullets -- although advances in molecular marker mapping could one day speed up the process of selecting desirable traits (such as disease resistance, crop yield, and, since we're dreaming here, guava-mango aroma). As Dr. Townsend explains, "There's a reason that Fuggles, Saaz, East Kent Golding, and similar ancestral varieties selected before 1900 are still used today: hop aroma and flavor is an exceedingly complex beast and very difficult to select for."

Planting the Seeds of Future Innovation

Every paradigm shift, every great revolution, has to start somewhere. The prize starts with a vision. The sensory panels will help bring the prize into focus. Amping up oils (after first determining which of the 200 plus hop oils are useful) presents challenges that are orders of magnitude greater than the shade tree mechanic task of boosting the alpha juice.

Put simply, when it comes to tinkering with aroma oils, the current state of the art is somewhere between 1st and 2nd grade. Using conventional breeding methods, we can of course get to the “promised land” in my lifetime – and we will much sooner than that. But to get there repeatedly, in addition to bucket loads of data, ample amounts of sweat and tears and gobs of good luck, to paraphrase Mr. Spicoli from Fast Times : we're going to need to develop a cool set of new tools, pronto.

Indie Hops is naturally proud to sponsor OSU’s aroma hop breeding program and it was especially gratifying to see over a dozen OSU undergraduate “eager Beavers” helping out with the research effort. I also want to thank them for leaving me a six pack of their test brews – sniff, sniff, sip, sip... hmm... spicy with a whisper of anise and a minty fresh finish…

Roger Worthington
5/17/10

Interview with Dr. Shaun Townsend

Breeding a Bold New World of Aroma Hops

The quest to breed more desirable aroma hops, aromas and flavor, oddly enough, has never really begun. While breeders like Dr. Al have hit home runs on crafting hop cultivars with more alpha, or higher yields, or disease resistance, few if any public breeding programs have made new and better aroma oils their holy grail.

Until now. As we’ve reported, Indie Hops has sponsored a breeding and research program at Oregon State University which, for the first time, targets aroma hops. I spoke with Dr. Shaun Townsend, hops geneticist, about the new program that he’s pioneering along, along with his colleague Dr. Tom Shellhammer, a hop chemist.

Is there a Super Aroma Hop Profile?

The short answer, according to Shaun, is no. We can talk all day about total oils and specific oil compounds. But , but nobody really knows – largely because the research investment historically has been nearly nil—the association between particular oils (e.g., farnesene, linalool, humulene. Gerianol, citral, limonene, etc) and definable and discrete flavors (e.g., floral, piney, citrusy, spicy, herbal, etc). remains naggingly unclear.

“There’s a glaring gap in our knowledge on how hop oils and their constituents interact to influence the taste and flavor of beer,” said Shaun. “There’s not a blue print or road map that tells us which oils to amp up or tamp down, or how do either of these compounds might be genetically associated.” The acids, on the other hand, are relatively simple, he said. “Just look at CZT [Columbus, Zeus, Tomahawk]. In a few decades the high water mark for alpha acids went from around 11% to around 18 to t 19%.”

In contrast, Hhop oils, Shaun muses, are a more “complex beast.” Hornbook biology teaches us that the traits of a particular plant are influenced by genetics and environment. The exact contribution, however, is not well known. We know that soil, climate, pests insect invasion, and temperature are a huge influence, he says, but there’s a “gap in our knowledge” when it comes to connecting specific DNA sequences to specific oils that wind up in beers that register in our brains as having particular qualities.

Do You Start with A List of “Super Aroma” Target Traits?

Again, the answer is no, at least for Shaun. We know from the literature that aroma hops are associated with certain traits. For example, aroma hops are generally defined as having:

* Low alpha acid content (less than 5%)
* Low myrcene oil (less than 50% of total oil)
* Low cohumulone alpha acid
* Alpha acid to beta acid ratio near 1.0
* Poor storageability
* Medium total oils content (.5 to 1.5 % of the whole hop)
* High humulene to caryophyllene ratio (above 3)

These are decent guidelines, but under OSU’s new aroma flagship program, defining worthy traits is the domain of Tom, while Shaun will attempt to breed for those selected traits.

To help identify the hops which may express desirable characteristics, Tom will be orchestrating hop sensory panels over the next few years. The panels will consist of experienced craft brewers, who will be asked to identify and describe flavor and aroma qualities of various hop brews. The data analysis from the sensory panels will be fed to Shaun, who will in turn cross targeted female and male hops for breeding, using conventional breeding techniques.

How does the Breeding Work?

Using Tom’s data, Shaun should readily identify the female plants. Choosing the male crossing partner, however, will be more difficult. Why? It boils down to who’s got the most accessible humulus lupulin. Females are teeming with it, but males – not so much. Their resin glands are much, much smaller, making it harder to harvest resin for analysis.

“We aren’t exactly shooting in the dark,” assured Shaun. “We have several decades worth of data on breeding stock. Since males don’t produce cones, it will be harder to identify the best males with an optimal oil profile, but it can be done. Basically, if the oil profile from the progeny of a particular male is desirable, we can trace the genetic contribution back to the male partner. It just takes lots of sampling and testing.” And the patience of Job.

Once seedlings are available, they are tested for Downey and Powdery Mildew and viruses. Weirdly-shaped, runty or puny “off-types” are culled out - the bad phenotypes. The vigorous chosen few are then transplanted to the field, where over a 3 to 4 year period they’ll be evaluated by the usual criteria (yield, disease resistance, appearance, size, etc).

Can New Technology Speed Up the Selection Process?

As we’ve learned from the People’s Hopmesiter, Dr. Al, the process of breeding, selecting, planting, harvesting, testing and releasing new hop cultivars can take up to a decade. Is there a short cut?

The short answer, again from Shaun, is “yes” for mega crops like corn, soybeans and wheat, but a strong “maybe” for hops. The idea is to associate genetic markers with desirable traits (e.g., citrusy aroma). Once DNA sequences are mapped and understood, scientists could simply study the sample leaf tissue of seedlings for genetic markers (without destroying the plant). They wouldn’t have to wait for the 1 to -2 years it takes for females to yield plump cones before they could run their battery of tests.

The technique, known as “Marker-Assisted Selection,” would allow breeders to plant hundreds and hundreds of female seeds, grow them into small plants, and pluck the leafs for DNA analysis. Using reliable molecular markers from seedlings to identify “home runs” would shorten the breeding program by many years, save tons of money and speed up the process of inventing new “designer” aroma hops.

Of course, all of this is years away. But the journey has begun, thanks to the work of Shaun’s colleague, Dr. John Henning, who has been working on genetic markers, mainly for yield and disease reistanceresistance, at the USDA-ARS Hop Lab in Corvallis, Oregon for the better part of the last decade.

Of course, we’ll still need to somehow associate particular DNA sequences with particular flavors and aromas, a herculean task further complicated by the changes a hop undergoes during its life and brewing cycle, depending on the terroir and brewer.

Variation is the Spice of Life

Dr. Townsend is like a kid in the candy store. “I’m very excited about the program, “ he said. “There’s so much to love about beer and hops, but there’s so much we don’t know.” Shaun is optimistic that with the data from Tom’s hop sensory panels, he can ramp up the process of selecting female and male partners for crossing, the results of which can be tested later on down the road..

Indie Hops shares Shaun’s enthusiasm. Hop science is on the cusp of harnessing the power of new technologies that have the potential for transforming how we go about breeding new hop cultivars. Consumers of craft beer want variety. They want to experience new aromas and flavors, from the big and bold to the faint and subtle. Unlike the industrials, whose mantra is “consistency,” crafties are shooting for the “new and different.”

The OSU breeding program is as big and bold as the richest pale ale. Instead of delivering one thing – more alpha acid – OSU’s finest aim to unlock the hop oils treasure chest. Tucked away in each pouch of mysterious humulus lupulin, there are as many potential flavors and aromas as there are human moods, temperaments, and personalities. This is the start of a brilliant new beer world in which brewers will be free to cook up a diverse roster of beers showcasing endless combinations of new and dazzling aromas and flavors, limited only by the imagination.

Roger Worthington
3/15/10