Hops have grown around the town of Žatec for a thousand years.

After the US and Germany, no country grows more hops than the Czech Republic, and 80% of Czech hops grow near Žatec in northwest Bohemia. “It’s the best place for producing these hops,” says Josef Patzak, Executive Director of Chmelařský Institut, the hop institute in Žatec.

“There are mountains 50km to the west. Clouds go above and it makes a rain shadow,” he says, meaning low rainfall and higher-than-average temperatures. “Also there’s specific soil here. Red soil that’s rich with iron. Hops like it.”

The most famous hops from the region are žatecký poloraný červeňák, better known to the beer world as Saaz, which is the German name of the town. Locally they think of hops as ‘green gold.’

“In the market, hops were an expensive crop and made very rich people here,” Josef tells me. “And still we keep our treasure and heritage.” These hops are so important that Žatecký chmel, or Saaz hops, have a Protected Designation of Origin (PDO), and in 2023 Žatec and its hop fields were granted UNESCO status.

“Czechs simply can’t imagine their pilsner without Saaz hops,” says Martin Macourek of the Czech Beer Alliance. They arguably have a longevity and legacy far greater than any other hop in the world, and an aroma that’s definitive of the plant.

Bohemian hops were known from the 10th century and there are several reports mentioning hops from Žatec in the 11th century. With increasing reputation for their quality, in the mid-1300s Emperor Charles IV actively encouraged the planting of more hop fields in Žatec and saw their export add more gold to his royal treasury. Though that didn’t last long, as wealthy Bohemian nobles feared the competition, and Charles IV issued a ban on the export of hop plants under penalty of death.

The most significant advance of Saaz cultivation came with the perfect overlap of industrialisation, the revolution of lager brewing and in particular the first pale lagers of the 1840s (brewed in the Bohemian city of Pilsen, and later taking their name,) and a growing transportation of beer which saw brewers creating beers inspired by another place. This shifted Czech brewing from small-scale and local towards the large-scale international industry it is today.

““Czechs simply can’t imagine their pilsner without Saaz hops.””

— Martin Macourek, Czech Beer Alliance

Žatec hop farms more than quadrupled in acreage from the mid-1800s to the early 1900s, with over 9,000 growers in the town. The world began to taste golden lagers made with the finest aromatic Saaz hops—and wherever lagers came to be drunk, the bright, distinctive aroma came to be a defining characteristic of this new beer style.

Domestically, “until the 1990s, 100% of brewers in the Czech Republic were using Saaz hops, and of these, at least 95% were only using Saaz hops,” Martin tells me, and while that may have been forced through the politics of the country, “still today nobody would think of not using Saaz hops.”

Saaz is a noble hop. A landrace variety which was found wild and grew in and of its place, uniquely of the land and weather, and which in turn influenced the beers it made. Saaz is low in alpha acid and high in oils, meaning it doesn’t contribute much bitterness, but it adds a full and distinctive aroma. It’s a quality all the European noble hops—Saaz, Tettnanger, Spalt, and Hallertauer Mittelfrüh—share.

The Saaz we know today was selected by the Czech hop breeder Dr. Karel Osvald. He planted many Saaz clones and selected the best three, all of which are still grown. They are the same hop just with small epigenetic variation—the DNA is identical, but some genes express differently in different growing conditions. “One grows better near the river. One is good in hilly regions,” Josef explains.

Saaz has also been used in breeding. Three of the other most common Czech hops—Sladek, Premiant and Angus—were all bred from Saaz. New Zealand hops Motueka and Riwaka have Saaz parentage. It’s not just modern hops that are linked to Saaz: genetically Tettnang and Spalt are both from the Saaz family, so likely came from Saaz seedlings and consequent organic evolution.

It’s a mother hop, a grandmother hop, and given its thousand year history it led Leen Alberts to suggest Saaz is the queen of hops.

“Saaz is very important for our brewery,” says Martin Melichárek, director of Jarošovský Pivovar in Jarošov, Moravia, in the southeast of the Czech Republic. “We use mostly this hop because it is the best one, and it’s the best for Czech lager.”

“For me it’s an icon hop in the brewery business. It’s a must-have if you want to have good Czech lager,” he continues. “We are using this hop for its aroma. It’s smooth and it’s very intense.”

Their main lager—Jura—is brewed with only Saaz hops, while another—Matus—combines Saaz with Sladek. It’s that beer which inspired a collaboration with Siren Craft Brew for their 2025 Time Hop series of four beers brewed with four distinct hops. Together they brewed a classic Czech Pilsner.

“We don’t just want to tell the story of hops through IPAs. Lager is also important,” says Sean Knight, Siren’s head brewer. “With Saaz it’s about showcasing that a hop can be subtle and unique, and have nuances which can be very interesting.”

For Sean, the Time Hops series is asking: “How did a hop influence a style? It’s about the beer style it ended up creating, not only about the hop.” In a Czech Pilsner, that also means looking beyond the hop.

Saaz hops have been coupled with Moravian malt in pale lager for close to 200 years. They grow the width of a country apart—bitter hops in the northwest, sweet malt in the southeast—but Czech Pilsner isn’t possible without them both together. Though ingredients alone don’t make a Pilsner, and process is crucial to a great Czech lager.

““We’ve got exactly what we want from Saaz in a beer because brewers have been making lagers with it for so long.””

— Sean Knight, Siren Craft Brew

“What makes Czech beer unique is probably not Saaz hops, actually,” Martin Macourek tells me, “it’s the unfermented content in the beer.”

Drink a Czech Pilsner and it has a full body and residual malt sweetness which is then balanced by a high bitterness and the oily and aromatic Saaz hops. Other lagers have a crisp dryness, but Czech lager is bittersweet and hoppy.

Melichárek worked with Knight on the recipe for the Time Hops lager and suggested using Czech Pilsner malt plus some caramalt to replicate the character of a classic Czech decoction mash (which Siren can’t do on their brewkit) to create that rich malt base. The hop schedule is similar to Jarošovský’s Matus.

“More and more Saaz are added through the process,” Sean says. First it’s just Sladek for bitterness, then Sladek and Saaz, then just Saaz, and finally a dry hop with Saaz. “It’s moving from one hop to the other,” he says. For both brewers, the dry hop is an elegant addition, there to impart that quintessential quality of the hop.

“Saaz has stood the test of time,” Sean says, and Czech Pilsner isn’t a style that wants to be experimented with. “We’ve got exactly what we want from Saaz in a beer because brewers have been making lagers with it for so long.”

But all this doesn’t mean that Saaz is an easy hop to understand. Modern hops are bold, juicy, pungent and identifiable from an abundant fruit bowl of flavours. “The hoppy aroma of Saaz is not so easy to define,” Josef tells me. “It’s mainly herbal, sometimes hay, grassy tones, floral tones.”

He believes that Saaz is more fundamental than that.

“It’s my idea that ‘hoppy’ aroma is exactly from the Saaz.” When you think of the smell of hops, it’s not Cascade or Citra or Golding or Tettnang. “Hoppy aroma is Saaz,” he says.

“One thousand years and we know that some knowledge in our brain is genetically inherited. I think that people who drink beers using Saaz hops, they say: ‘this is ‘hoppy’.”

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