Siren Time Hops 2025 — Part Three: Nirvanic Nelson Sauvin
New Zealand hops are special. Fragrant and zesty, their unique profiles strangely represent likenesses to the famous Sauvignon Blanc wines made there—grapefruit, kiwi, gooseberry; freshly cut grass. In the 2000s, juicy, wine-like Nelson Sauvin found its place within the American craft brewing scene and became a go-to for West Coast IPAs and pale ales. Now, it’s difficult to imagine the beer world without it, as it becomes ever more embedded within the flavour profiles of modern beer styles from soft and hazy New England IPAs, to bright and punchy Cali IPAs with their light malt bases and fragrant, punchy hops.
Hops came to New Zealand some 200 years ago, when English and German colonisers began to farm hops in the ideal climate of the South Island countryside. By the 20th century it had become one of New Zealand’s largest industries. By the 1950s, New Zealand was a world leader in hop breeding and cultivation and in the ‘60s, new varieties Smoothcone, First Choice and Calicross were all introduced into hop gardens.
These hops were important for another reason too—before they were grown for flavour, they became the country’s main fightback against Phytophthora which ravaged the New Zealand hop industry in the 1940s. This fungus, also known as black root rot, destroyed entire crops. It was only thanks to intervention by hop scientists led by Dr. Rudi H. J. Roburgh’s hop research station that resistant strains were found, bred, and planted to mitigate the damage and rebuild the industry.
Dr. Roborgh’s hop research work also became the only research in the world on breeding seedless hops known as “triploids”, which became the ancestors of Nelson Sauvin and Motueka. These hops have become synonymous with New Zealand pale ales and IPAs, with floral esters and tropical, wine-like flavours.
“That’s why I wanted to use Nelson because it’s got such a distinct link to terroir,” says Sean Knight, Siren’s head brewer and one of the minds behind this new collaboration.
“I’d never actually had Pernicious Weed. We spoke a lot with the folks at Garage Brewing and one of our thoughts was to do what they were doing with the hops and use those techniques to modernise what the Californian brewers are doing.”
That choice was made to really highlight the true character of the Nelson Sauvin within the beer. “Breweries over in California have gone as far as to brew with lager yeast to really create that light canvas on which the hops can really shine.”
For Siren to create a beer that showcased the true essence and character of New Zealand hops, Garage Project was an obvious choice for partnership. Their embedded involvement with the Hāpi Research Project in Aotearoa aims to secure the future of the New Zealand hop industry, protecting the region’s terroir and supporting research, innovation and market development.
“There was only one hop provider—New Zealand Hops, a co-operative—until recently,” says Pete Gillespie, Head Brewer at Garage Project. “Their approach was to homogenise everyone’s hops and create a standardised type or style. Of course, this didn’t encourage innovation or individuality.”
““I wanted to use Nelson because it’s got such a distinct link to terroir.””
When your hops are being collected together with everyone else’s, it’s not like you’re going to go out of your way to grow excessively high-quality, high-performing hops. Their unique flavours and aromatic profiles would be lost among the rest. With the advent of individual hop providers, growers could really select hops for their individual merits, and brewers could begin to choose hops specifically for their quality.
“We’re in year seven of the Hāpi Project now,” says David Dunbar, the founder of Freestyle Hops, one of New Zealand’s first emerging independent hop producers. “We’re pumped—we now finally have hops that people can taste in their beer.” He’s not exaggerating, the smile on his face says it all. This work is exciting.
The Hāpi Research (HRL) project in Aotearoa is a commercial joint venture between Garage Project and Freestyle Hops with the aim of leading global aroma hop innovation in New Zealand by breeding exceptional new varietals that brewers are looking for all over the world.
“It’s an iterative and long process to go out into the field and find what’s going to make really good beer,” he says. “We’ve been evolving with brewers how we grow and when we harvest.”
To find the best hops, the ones that are perfectly ready for picking, sensory evaluation is the only way. Skilled hop growers and producers like David will go out into the field and rub the hops between their hands, smelling the lupulin staining their fingers and searching for the aromas they need. Sometimes, the skill is in knowing which aromas will fade and which will become more apparent during the brewing process—not every hop that smells great is automatically perfect. Not every hop that smells of onions is a dud.
Of course, using sensory evaluation takes time and limits testing to small amounts of the total crop. However, David says that unlike winemaking, where harvest readiness is checked by testing sugar content in grape juice, it would be much harder for technology to define what exactly he’s looking for in a hop.
“People are very good at sensing that tropical element at low levels—the entire sensory matrix is important, deciding what will appeal to drinkers and brewers is difficult and I can’t envision a scientific text ever doing it,” he says.
Originally, the Nelson Sauvin that the growers were looking for were bright and fragrant hops with plenty of white wine character. “For this beer we’re harvesting at extreme points, working to the very limit of when they are pickable,” says David. “It’s taken practice but it’s paid off. We’re getting aromas and complexity never seen in Nelson Sauvin before, and it’s interesting and fascinating to see that evolution.”
Illustrations by Dionne Kitching
There are many ways that the surroundings of a hop yard can influence the character of a hop. Pete says that alongside terroir, light hours and temperature, the picking window is an essential consideration for deciding the resulting flavours of a hop.
“When you have the opportunity to choose the best picking window for your hops, you’re able to harvest them for their flavour,” Pete tells me. “When they are at their peak, they lose weight, that’s why most hops aren’t picked at this point—if you’re being paid by weight, why would you harvest a lighter product?”
But what’s lighter in volume is more intense in character. “Nelson Sauvin from the right picking window has more of that tropical flavour, and a dankness,” Pete says.
“It’s a wonderful hop, it has so many moods. When you pick it early you get even more of those thiols that taste like Sauvignon Blanc—exactly the same Thiols you find in the wine, actually. It’s amazing, isn’t it?”
The hops used in Garage Project’s flagship Double IPA Pernicious Weed are Nelson Sauvin and Rakau, New Zealand through-and-through. In bringing the beer into 2025, the brewery wanted to make sure the evolving characters of these hops were effectively showcased, allowing their paired qualities to shine.
“The beer is more tropical now,” David says. “A bit more perceived sweetness, with as much stone fruit and complexity as we can take from the Rakau.”
Rakau is a vital part of the Pernicious Weed whole, bringing harmonising notes to Nelson Sauvin’s bold tropical fruitiness.
“Alone, Rakau is always just Rakau,” Pete says. “It’s good, but it can’t be anything else, it’s not what you’d call interesting. But with Nelson Sauvin, it’s a perfect combo—it brings out the tropical in a way Nelson can’t do on its own.”
“We’re getting aromas and complexity never seen in Nelson Sauvin before, and it’s interesting and fascinating to see that evolution.””
David agrees. “Rakau can have too much of that stone fruit flavour with no punch. You need a lot of Rakau for it to be intense enough, and then you’d start to have more vegetal aromas and flavours coming through simply because of the amount of green matter you’re using. But as a supporting character for Nelson Sauvin, it’s ideal.”
It’s exactly this character of the two hops that makes Pernicious Weed such a special beer—Nelson Sauvin and Rakau working together as a dream team to create something fresh from a modern classic recipe. It’s no wonder the entire Siren team were so keen to work with Pete and the Garage Project crew on an updated recipe that celebrated the hops that make this beer, and brewery, so revered among the beer-loving world.
“Brewing P-Weed is like performing a jazz standard, you take the best parts and you run with it,” Pete says. “The beer itself has really changed dramatically over time, it’s a canary in the mines for New Zealand hop varieties showing how they too have improved and evolved.”
To Pete, Pernicious Weed is a relic, but one he’s excited to polish up for a new audience. “I wouldn’t design a recipe like that these days, it’s old fashioned, it’s full of crystal malt and it’s excoriatingly bitter. People want different things now, and that’s why I’ve looked at California Pales for inspiration—not too bitter like a West Coast, not an East Coast that tastes like fruit juice, somewhere in-between.”
“We used German pilsner malt and a little bit of English pale ale malt (two-thirds to one-third) and a little bit of sugar to lighten the colour and get the ABV up to 8%,” Sean explains. “This gets us a nice clean base.”
The way in which the beer was made was all new to Sean too. “What we’ve done with the hops is what Pete does, put them all in at the beginning, which I thought was a bit crazy. I was madly sceptical because I wanted it to really show the Nelson character, but I trusted him and it worked.”
Home in New Zealand, Pernicious Weed is a beer that everyone knows. It’s in the fridges at the bottle shop and ready for you whenever you fancy something fresh, fruity and delicious.
“I find it really interesting that Pernicious Weed hasn’t had to change its recipe over the years,” Sean says. “This is the only beer in the project where we’ve done an homage to a distinct beer rather than a style.”
Does David the hop specialist rate it as a beer that can show off the qualities of his beloved Nelson and Rakau? “Ah yeah, I’ve had a few. Pernicious Weed is always there for you,” he says. Even though it’s a classic in the grand scheme of the craft beer revolution, this revamped version shows there are still new ways to be surprised by our old favourites.
“Beer has been around for thousands of years and we’re still finding ways to be excited about it,” he adds. “There’s still more to be found.”
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Siren’s incredible Time Hops series of beers is out now and can be purchased on their webshop here, and from independent retailers across the UK. Fancy 10% off your order too? Get subscribing to our Patreon and earn yourself a discount code.
