A Decade in the Making
Humulus lupulus, most commonly known as hops, is a perennial fruiting plant that has been used in beer production for centuries. Beer is where the hops end up, but where do the hops come from? The first documented hop cultivation occurred in Central Europe in the 9th century1, with evidence from 10th century England that hops were commercially cultivated and traded between countries.2
For centuries hops were viewed as a homogenous crop with no differentiation. It was not until 1669 when the differences between hop varieties were first documented by John Worlidge, who wrote in his Systema Agriculturae—the Mystery of Husbandry Discovered that, “There are also two sorts of Hops, the green and the brown, the one yielding better colour by much when they are dry, the other bears larger and greater quantity of Hops which is rather to be preferred.”
Since then the number of recognized hop varieties has exploded, with more than 150 unique varieties now commercially available. The very first recognized varieties were specific to their growing regions, Saaz in the modern-day Czech Republic, Hallertau and Tettnang in Germany, and East Kent Golding in England.
By 1900 there were 60 recognized varieties worldwide, but many of them shared the same genetics and again were only distinguished by growing region. In biology this is commonly referred to as a landrace because they are all genetically similar, but vary slightly due to environmental adaptations and regional differences. As an example, Golding was a popular English variety that had many named variants such as Canterbury, Eastwell, and Early Bird based on where they were grown or the specific farmer who grew them.
Of the original noble hop varieties, Fuggle appears to be the lone standout as a distinct variety since it was reputed to be selected from a chance seedling in 1861.3 However, this origin story has been disputed as recent genetic testing indicates that Fuggle could possibly be a clonal variant of Savingjski Golding. But even though differences in varieties were well known, it was not until the early 1900s and the rediscovery of Gregor Mendel’s genetic theory that the scientific breeding and development of hops began.
The practice and understanding of modern hop breeding started in 1904 at Wye College in Kent, England when Professor Albert Howard started the Hop Breeding Program. The first crosses were planted out in 1906 under Professor Earnest Stanley Salmon and became the basis for all of the hop breeding to follow. Not only did Professor Salmon pioneer the process of hop breeding, but he is also responsible for one of the most influential hop varieties, Brewer’s Gold. Brewer’s Gold can be considered the matriarch of modern hops as its genetics are found in some of today’s most popular varieties including Nugget, Centennial, and Citra®.
Public or Private
Not long after the program was started at Wye, other countries started their own hop breeding programs based on the same science and methods. America started its first public hop breeding program in 1908, but this first incarnation did not last long and was soon discontinued only to be later restarted in Oregon in 1931. Denmark and Japan were the next countries to establish public hop breeding programs, but they were later privatized and incorporated into the Carlsberg Brewery in Denmark and the Sapporo Brewery in Japan. Germany created their public program at the Hüll Hop Research Institute in the 1920s with the intent of breeding disease-resistant varieties after their hop crop was devastated by downy mildew. There is an important distinction to make between the public breeding programs like the United States Department of Agriculture and the privately-owned programs of Sapporo, Carlsberg, and the one in South Africa that is now owned and operated by AB-InBev.
“There are both public and private varieties,” said Judith Thoet, the Co-Technical Director of the US Hop Research Council (HRC). “The public varieties have been the cornerstone of hops in the United States, whether they originally came from Germany or England, and then, of course, there have been a number of varieties that have been developed in the United States throughout the past century.”
US public varieties like Cascade, Centennial, and Chinook are available for any farmer in the country, but they are also available for anyone to grow at their home. “The bulk of the funding for public varieties does come from the federal government because the breeders are (employed by the) USDA ARS (Agricultural Research Service),” said Thoet. “And that means those varieties are in the public domain and are available for anyone to grow. And if I had to point out one major difference between public and proprietary varieties it is restrictions. Proprietary varieties come with a lot of restrictions that are placed on the farmer, because the varieties are owned by the breeding companies, so the growers need to enter into contracts with those companies.”
Because the proprietary varieties are owned by the private breeding program even the farmers that grow them do not own them. “The contract stipulates things like the amount of acreage they are allowed to grow and in fact if the breeding company wants to reduce acreage, they can make the grower reduce acreage of that specific variety. This allows them to control the supply and how much is out in the market,” said Thoet. “There aren’t any restrictions placed on the public varieties so farmers can grow as much or as little as they want.” However, not all restrictions are bad. Not only is the supply of proprietary varieties controlled, but so is the quality. If a particular proprietary lot is not true-to-type or does not meet quality standards, then language in the contract might be enforced and prevent the farmer from selling it.
Even though the public program was established early in the U.S., proprietary varieties like Citra® and Mosaic® are currently the most popular varieties on the market. Citra® on its own accounts for almost 20% of the total hop acreage planted in 2020. “It was only about 10 years ago that proprietary varieties really started to get popular,” said Thoet. “Originally they were looking for things that weren’t available in public hops, but then the proprietary varieties started to do what had been done in Europe for many years where they charged a premium or a royalty that would go back to the private company to continue with their breeding purposes.”
Simcoe® and Amarillo® were two of the first proprietary varieties in the US with trademarks for both filed in 2000 by Yakima Chief Ranches, LLC and Virgil Gamache Farms, respectively. However they were not necessarily the result of a private breeding program. Amarillo® was unique in its own way, due to the fact that it was a discovered variety and not the result of an intentional cross. The original bine of Amarillo® was found growing in a field of Liberty in 1990, but it looked and smelled so unique that it was propagated out over the next decade.
Those first two patented varieties did show the potential for proprietary breeding programs and gave rise to the Hop Breeding Company, LLC (HBC) in 2003, which is a joint venture between John I. Haas Inc. and Yakima Chief Ranches, LLC. HBC’s hop portfolio consists of some of today’s top varieties like Citra®, Mosaic®, and Sabro®. (Now is a good place to point out that I work for Yakima Valley Hops, which John I. Haas Inc. has a financial stake in.)
While the private breeding programs were growing in the US, the public program was facing challenges. “Over the past decade there are a few things that slowed down the public hop breeding process,” explained Thoet. “The public hop breeding program at Washington State University in Prosser was essentially closed, and I think that happened in 2016. And the federal government funding for the hop breeders in Corvallis, Oregon was low, and because of that only about one third of Dr. John Henning’s time was dedicated specifically to hops. There were a couple of times where there was a real threat that the federal hop breeding program would actually be closed.”
Right now there is only one program that is dedicated to developing new public domain hop varieties, which is the program nested within the USDA Forage Seed and Cereal Research Program under Dr. Henning in Corvallis. Thoet said that this downward trend in public funding has changed recently due to lobbying efforts. The Brewers Association has also made a public trust agreement in 2019 with the HRC and pledged grant money to help develop and promote public varieties. “Something that we just started last year (2019) was the Elite Line Grow Out Program, which the Brewers Association provided the seed money for, and this program allows us to grow out some of the most promising varieties in Washington, Oregon, and Idaho for farm evaluations. This also means there is now sufficient plots planted so that breweries will be able to run trials of these lines in 2020 and 2021. The combined effort of all of our partners and members has injected renewed vigor into the public hop breeding program and is creating a very bright future.”
Process and Timeline
Michael Ferguson is the Director of Hops Breeding at John I. Haas in partnership with the HBC. He said that he had been an obsessive homebrewer since 1999 and was fortunate to be able to merge his hobby with his plant breeding profession five years ago when he moved from breeding strawberries to breeding hops.
“The fun thing about hop breeding is that they are dioecious (male and female plants), which makes breeding hops more challenging than other things,” said Ferguson. “But it also brings fun and allows for
more creativity.”
Because hops are dioecious, the female plants (the ones that produce the hop cones) require pollen from the males in order to produce a cross in the form of a viable seed. Seeds are only used in creating new variety crosses, whereas root cuttings or rhizomes are taken from established plants in order to preserve genetic consistency.
“When you make a cross you have two options, or really three. You can use a single male, you can use a bulk of males from that family, or, as is most commonly done, you can just use open pollination,” Ferguson explained. “Many cultivars currently are the result of that open pollination. But for me as a breeder I’m not interested in that at all. Because I’m trying to deliver a predictable outcome, so for me I do no open pollination because why would I do that if I’m trying to get data and use data on both the male and female side. Open pollination is just randomness and I’m not getting paid to do randomness.”
Because hops inherit genetics from both the mother and the father, it is important to understand which genes are dominant and recessive. “You really need 4–6 years to learn a male’s value,” said Ferguson. “And ultimately it comes down to heritability, which is why I use bulks. It gives me essentially an average of that family’s impact on the heritability.”
In that first year’s time the cross is made in July, seeds are harvested from the cross in October, seeds are germinated the following January, and then they are planted in May. “So really in less than a year you made a cross and planted those seedlings out,” said Ferguson. “I’ll probably make 75 crosses for males per year and will collect pollen off of probably 75% of those just so I have as many options to look at as I can. So then in the off season I go through and look at all of their data and see what I can use from those males and plan my crosses for the upcoming year.”
Ferguson said that it is important to have a large bank of pollen from the males, “because if your female is ready and you don’t have (pollen) then you’re just grabbing. And that’s why I think there’s so much open pollination, because you have a female that you’re really excited about, but you don’t have males ready to go.”
Making crosses is a game of big numbers. Ferguson explained that the more data and statistics you have on crosses, the higher probability you have of making a cross that can go the distance. “We plant out 10–20 thousand seedlings per year and only 1–2% of that population gets saved and moved to the next stage of testing.”
The varieties that do progress are picked based on genetic markers for certain traits, initial agronomics, or even interesting outliers that might offer something unique to a gene pool.
The next stage consists of moving the promising plants to a common field where they are planted in a single hill or propagated out to seven hills. This is where varieties are assessed for their agronomics and disease resistances, but it takes at least three years before there is enough data to be statistically significant.
“There’s many ways you can slice it, and hops are notorious for taking at least 10–15 years to develop a new variety, but the big thing in breeding is how you look at your process,” said Ferguson. “There’s always ways to be more efficient and chop years off the process. There’s no reason why it has to be that slow, the plant doesn’t require that much time to grow, but it’s the process that takes so long. Really we can get something in front of the brewers with a fairly good understanding by year five or six, but then they require at least two to three years of doing brewing trials. And so if you can be more efficient in your process from the breeding side, that’s essential because you’re not going to be able to shorten other things in
the process.”
What qualities are hops bred for?
Hops are complex little plants and have many different qualities and characteristics that they can be bred for. The main things that determine the success of any given variety are yield, disease resistance, alpha acid content, aroma compounds, picking window, and how well the cones can be harvested, picked, and processed. In order for a variety to find success in the marketplace, it must meet all of these requirements because it is not enough to simply excel in some or even most of these areas.
It is also important to remember that different qualities are important to different industry players. Farmers, brewers, and beer drinkers all play a role in the success or failure of a hop variety, but there is very little overlap in what each group prioritizes or seeks out.
Pickability and harvest window (more about this in the “Window of Opportunity” sidebar below) are extremely important to the farmers and processors, but those characteristics have very little impact on brewers. Beer drinkers seek out beers that use hops because of their specific flavor and aroma, but not every hop that tastes or smells great is disease-resistant or yields enough to warrant a farmer planting it. And even if a brewer knows about the best tasting hop for the style they are brewing, they are not always able to source it, because it is not cost-effective or there is a breakdown in the supply chain. That is why it is so difficult to find the next superstar hop variety that farmers want to plant, brewers can brew with, and beer drinkers want to purchase.
“Obviously yield is always the primary component that we breed for,” said Ferguson. “That’s something that I think the industry as a whole has to pay more attention to from basically a sustainability and risk perspective. If you have higher yields, then it means you have lower risk for the whole system. When we are looking at a hop, if we are going to pursue it now it has to yield at minimum 2,000 (pounds per acre). There are currently a lot of hops in the industry that are well below that mark and that just means higher risk and less flexibility when looking at contracts. And 2,000 is achievable, but there just needs to be a bit more discipline from the breeding side.”
Thoet said that yield is also one of the primary things that they breed for, but a comprehensive disease and pest resistance package is equally important. “We are also breeding hops with the future in mind and what the future of agriculture is going to look like. That future could include water conservation. There are varieties out there that are better utilizers of water so that is one key trait that we are keeping in mind.”
The agronomics are important to the farmers, but it is the brewing qualities that brewers are concerned with. Brewing qualities include alpha acids, total oils, and the flavor and aroma compounds. “For us, alpha is the easiest to breed for because there’s no subjectivity to it,” Ferguson said. “It’s purely quantitative. What does it yield and what’s the alpha? You still need to be creative with alpha hops, but there’s just so much hard math behind it.”
Alpha acids are just one of the hundreds, if not thousands, of compounds that hops can produce. Myrcene, humulene, and caryophyllene are some of the more common compounds, but there are hundreds of other named compounds with more being discovered every day. Some of those compounds contribute to flavor and aroma in extremely low concentrations, like parts per million or even parts per billion. Some of these trace compounds present only in certain varieties, but those characteristics can be magnified through the breeding process.
“Right now 4-MMP is really interesting to me,” said Ferguson. “I have a fixed amount of space that I can breed in, but for a percentage of the population I definitely want to take that genetic marker for 4-MMP and make like 500 seedlings within that population. Am I going to use that marker in all of my seedlings? No, because that’s not the only thing I’m looking at, but hell yeah, if I can apply that marker and be more efficient and really try to jack that trait up through the roof in that population, yeah that would be really cool.”
Even though all these compounds are quantifiable, looking at a data sheet will not always give you an accurate representation of what that hop has to offer. “Hops are even more challenging and complicated because there’s the whole process of brewing,” Ferguson said. “Most things in plant breeding are a direct evaluation, whether it’s corn or strawberries, I can just take a bite of the fruit and immediately know if I had something that tasted amazing. But with hops you absolutely have to brew it. When I first started, it was soul crushing for me to come to the realization that a hop could smell great but do absolutely nothing for a beer it was brewed with.”
This is why releasing a new hop variety is such a collaborative effort between breeders, growers, and brewers. Hops only show their true character in the final beer, so many different brewers need to brew many different styles over years in order to start understanding a variety and
its potential.
“Working with the craft brewer population is essential to make good decisions in the supply chain,” said Ferguson. “Whereas small brewers were at the fringe even just a decade ago, they were passionate about aroma hops and now they are fully integrated into the development of these hop varieties.” Even medium-sized craft breweries did not always have access to experimental varieties, but Ferguson said that today they are essential to the development process of new hop varieties.
Window of Opportunity
In the Northern Hemisphere the hop harvest usually starts in late August and is wrapped up by the early part of October. Each hop variety ripens at a different time in the season and if they are picked too early or too late then they might be undesirable. This prime picking time is referred to as the picking window.
If a hop is picked too early then it will not have had enough time to produce the oils and alpha acids, making it less potent. Hops that are picked too early also tend to have an underdeveloped aroma or flavor that is grassy or green. If a hop is picked later than it should be, it usually presents with pungent onion or garlic aromas. Not only does each variety ripen at its own time, but the length of the picking window varies by variety as well. Some varieties are at their best for a week or two, but only a day or two
for others. The picking window is particularly important for aroma varieties, because missing the prime picking window might mean that the entire lot is unsellable. Alpha varieties are not as concerned with aroma, so farmers usually let those hang as long as possible to maximize alpha acid production.
Hop breeders are not only competing against other hop breeding companies, but they are also competing against themselves in a way because they need to keep picking windows in mind and make sure that every variety does not ripen at the same time. “If you look at the hop acreage reports, Citra® is the beast and Mosaic® as well, so from our HBC grower group perspective, those two varieties alone dictate the picking schedule because they require at least 10 days up to 14 days of kiln space (and hops must be kilned immediately after harvest to preserve before baling or pelletizing). So there goes half of September right there,” said Ferguson. “Now if it is a variety that falls in that main middle pick window it has to be exceptional on both flavor and other attributes for us to increase the burden during that time.”
Because Citra® and Mosaic® take up such a huge chunk of both acreage and kiln space, HBC breeders are trying for varieties that fall on either side of their picking window. “Early period we’re looking at late August into the first week of September,” said Ferguson. “And on the late side
we shoot for the end of September into the first week of October.”
One of the newest varieties to be released by HBC is Sabro® and it was instantly a perfect fit in their hop portfolio. Not only is Sabro® an incredibly unique aroma variety, but it ripens at the perfect time for them. “Sabro® is now our earliest variety that we have,” said Ferguson. “It’s right in that Centennial window and this year (2019 harvest) it was maybe even slightly earlier than Centennial. Which is nice because with Sabro® we really want to nail the aroma profile and make sure that it’s in the sweet spot when we pick it.”
As the harvest schedule starts to fill up, it means that it will be harder and harder to breed new hop varieties that will find a place in the market. But that does not mean that just because a variety is first to market that it is safe and will be around forever. A new variety, with similar aroma and flavor, could be released with better agronomics that makes farmers want to rip out their current field and replace it. Even the current queen of hops, Citra®, is not safe on her throne. “Breeding a Citra® replacement is actually one of my main goals,” said Ferguson. “Even though it is an HBC variety, we are aggressively breeding for a Citra® replacement ourselves, because Citra® only yields right around 1,400 to 1,600 pounds an acre, if you look at the five year average. And now that it’s the number one variety by acreage I’m breeding for something that offers that aroma, but with a higher yield. Because that will mean fewer acres that need to be planted, which will hopefully mean lower prices for the brewer and less risk for everybody.”
Not only is HBC actively breeding for a Citra® replacement, but so is every other breeding program. “Any time you get in a business scenario and when you get such a high market share as Citra® you know the competition is gunning for that type too,” explained Ferguson. “But with the yield being low, which causes the higher price for Citra®, you’re allowing the competition to come in and undercut you on price. So you need to be proactive about it and breed a replacement or eventually you’re just going to give that market share up.”
Releasing a new hop variety today is much more difficult than it was even just a decade ago. With more than 150 varieties commercially available around the world, the competition is stiff and the barrier to entry is high. “From the development side we constantly ask ourselves if there’s really a need for this or that new variety,” explained Ferguson. “At HBC we are getting more disciplined to only release varieties that are really impactful with unique flavors that brewers are after. We really look for varieties that get pulled into the market by brewers because we don’t want to push another variety on the market. Brewers should be coming to us saying we love this hop how do I get more of it. At the end of the day, the proof is in the beer and if you make something that throws your eyelids back.”
Sources
1 https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.1986.tb04370.x
2 https://nph.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1469-8137.1975.tb01429.x
3 https://naldc.nal.usda.gov/download/CAT30947736/PDF
4 USDA Hop Acreage report for June 2020
