Bitter harvest
Meet the Motueka plant geneticist who’s helped breed new hop cultivars now in demand from breweries and beer aficionados all over the world.
Motueka-bred hops are now in demand all over the world.
Dr Ron Beatson is a man happy to talk about hops. “Oh, I could talk about hops all day,” says the plant geneticist who has headed up the Plant & Food Research hop breeding programme from its Motueka site since 1984. “People just like working with hops. In fact, we often talk about ‘happy hops’ because people like working with hops so much. We should research the plant’s anti-anxiety properties.”
People have been growing hops – and using them to make beer – for hundreds of years. The oldest recorded food standard is the Reinheitsgebot, or German beer purity law, which states that beer can only be made using hops, malt and water. It was passed in the 16th century.
But we’re only just starting to understand the potential of this plant, Ron says. “I think it is one of the most underutilised plants grown. Sometimes it annoys me that cannabis seems to get all the scientific attention.”
Cannabis and hops are closely related; both members of the hemp family (Cannabaceae). Botanically they are very similar too, Ron says, although Humulus lupus is a vine whereas Cannabis sativa is a free-standing plant. “And hops is legal to grow, of course,” he adds. In the garden, hops is a perennial herb, the rhizome under ground behaving as a perennial, with vegetative growth shooting up in spring and dying back in winter. It’s latitude sensitive, doing best between 40oS and 48oS (Nelson, centre of commercial hop production in New Zealand, is 41oS), and it is the shortening of day length that triggers flowering and the formation of the hop cones. Hops are dioecious, meaning they have male and female flowers on separate plants, and it is the mature female inflorescence for which the plant is grown.
On the inflorescence are glandular hairs, technically known as trichomes, and on those is a sticky yellow pollen-like substance known as lupulin. And it is that which contains most of hops’ active ingredients. “The glandular hairs contain all the goodies you want for brewing,” Ron says. “Cannabis sativa is the same, it is the trichomes that contain the compounds people want. And in both it’s the female plants that produce the most.”
Scientists are not sure why the hops plant started to produce chemical compounds, Ron says. “We think it was for protection, as a natural defence mechanism.”
But hops ended up producing three chemical groups that are important in brewing: alpha acids, which make beer bitter and which have antiseptic qualities; beta acids, which have antiseptic qualities; and essential oils, which impart aroma and flavour.
To begin with, it was the antiseptic qualities that interested brewers. “Originally hops was added to beer because its antibacterial properties stopped the beer spoiling,” Ron says. “But then they realised it also changed the flavour.”
How hops change the flavour however, depends on when you add them. The alpha acids are not bitter themselves, Ron says, but during the brewing process, they are heated, which converts them to iso-alpha acids
“Hops has huge potential. It is one of the most underutilised plants grown. Sometimes it annoys me cannabis seems to get all the scientific attention.”
which then give beer its bitter taste. So if you add the hops at the beginning of the brewing process, the bitter flavours come through and other flavours from the volatile essential oils are burned off. Whereas if you add hops later, you get the “hoppy” flavours and aromas coming through, thanks to the oils.
Ron started working with hops almost accidentally. Doing his PhD in the United States, he received a study grant from DSIR (which has now become Plant & Food), which meant when he returned to New Zealand he went to work for the crown research organisation.
Ron had been working in kiwifruit but the head of the Motueka-based hop programme, Dr Rudi Roborgh, was about to retire, so it was suggested Motueka-born Ron might like to work on hops.
Rudi had spent years improving on hops’ disease resistance, splicing the European disease-resistant cultivars into the American varieties which were high producing but susceptible to a phytophthora known as black root rot.
But Ron decided to take the hop breeding programme in a new direction, concentrating on flavour. And when the craft brewing boom started in the late 1990s and early 2000s, there was a movement towards flavourdriven beers, such as IPAs, which demand hops that deliver aroma and flavour rather than bitterness. Luckily enough, there were the hop cultivars developed by Ron and his team which had unusual fruity flavours of citrus, tropical fruit, passionfruit and even stone fruit.
New Zealand hops are now in demand globally. While we produce a small percentage of the world’s crop, exports have increased four-fold in the last 15 years to about $20 million a year, and are expected to double in three to five years. “We were ahead of the game,” Ron says modestly.
Plant & Food are still looking for new hop stars. Ron’s team continues to make about 50 new hop crosses a year, producing between 2000 and 3000 seedlings. The best are grown on for a couple of years, then evaluated for commercial potential.
And how do you evaluate hops you may ask? By making it into beer, of course. For the last four years there has been a microbrewery – the Hop Lab – at Plant & Food’s Motueka site. It produces experimental beers using different hop selections which are evaluated by industry experts. Promising hop cultivars are then passed on to the industry to grow and trial.
Fancy planting a few vines for your own homebrew? Ron has a few words of warning. Before hops are used in brewing, they go through a complex drying process. “So I usually say, grow a few plants for interest, but buy hops from your homebrew store! The quality will be way better.”
Scientist – at Plant & Food and elsewhere – are also looking into this plant’s non-beer applications. “Compounds found in cannabis are being studied as a potential drug for epilepsy, as a treatment for Parkinson’s disease. Hops has very similar compounds, yet there would be a thousand times more research on cannabis than on hops. It is not a well-researched plant.”
But Plant & Food has already discovered a compound in hops that activates what is called the “bitter break” (an evolutionary mechanism that reduces appetite when we eat something bitter) and that is already on the market as a weight management supplement. Elsewhere there is research into hops’ potential anti-cancer properties, and whether it is a possible treatment for diabetes.
But while that work goes on, there is still interest – purely scientific, you understand – in making a better beer. “I do think I have the best job in New Zealand,” Ron admits. “That’s why I’m reluctant to retire!”
Dr Ron Beatson, along with beer writer Geoff Griggs, is giving two workshops on hops as part of Rapaura Springs Garden Marlborough from November 8-11.