AYESHA RASCOE, HOST:
The Czech Republic is known for its beer, specifically pilsners. But hotter, drier summers are making it harder to grow a key ingredient in beer - hop plants. Researchers in the Czech Republic are breeding new hop varieties built to survive a changing climate, as Katerina Barton reports.
KATERINA BARTON, BYLINE: A little more than an hour northwest of Prague, the small town of Zatec is known for two things - beer and hops.
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BARTON: Here at the Hop Research Institute, Pavel Donner pulls up an attractor.
PAVEL DONNER: (Non-English language spoken).
BARTON: (Non-English language spoken).
He works in the hop cultivation department, where he monitors all aspects of hop growing, including helping out with the harvest.
As we walk to his office, I notice a tattoo on his calf - a leaf with four green diamonds, which represent hop cones.
DONNER: Czech hops is usually referred as Czech gold or green gold. So the diamonds should, like, represent it's valuable for us.
BARTON: The most famous of the hops in the Czech Republic are a variety called Saaz. They're what give Czech-style Pilsners their signature crisp and bitter taste, but a changing climate is threatening them.
Like much of Europe, the Czech Republic experienced extreme heat waves and a drought this past summer. As a result, hop growers across the country saw their average yields drop by more than 20%. The high temperatures also affected a key compound inside hop cones called alpha acids, which are the main source of bitterness in beer.
DONNER: The alpha acid content this year is going to be really bad. The yield, bad. Alpha acid, really bad. And the breweries will have to use more hops to maintain the same bitterness level in their brand.
BARTON: Which is why Donner and his colleagues at the Hop Research Institute have been creating hop varieties that can resist extreme heat and drought.
Vladimir Nesvadba is the institute's head hop breeder. He started this research 20 years ago and says cross breeding new varieties takes years of research.
VLADIMIR NESVADBA: We tested 15 years. We tested through greenhouse and tested in field without irrigation, and this two varieties is the best.
BARTON: He registered two new drought-resistant varieties called Saaz Comfort and Saaz Shine in 2019.
Low levels of irrigation here mean that farmers rely on rain. But this year, rainfall in the Czech Republic reached historic lows, and experts warn that the super El Niño could bring a hotter and drier 2027, as well.
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BARTON: Nesvadba takes me out to one of the institute's many hop fields to see these new varieties. The plant's vines climb up giant wire trellises around 20 feet tall.
NESVADBA: Saaz Shine, Saaz Comfort, Saaz Brilliant.
BARTON: Nesvadba points to the top of the trellis. He tells me the hops tend to flower near the very top of the plant. But these varieties are full of hops and have flowers all the way to the bottom, which shows how productive they are.
NESVADBA: (Non-English language spoken).
BARTON: The original Saaz has been grown in Zatec for more than a thousand years, so it's a slow process to introduce new varieties to farmers and to breweries. But there are some microbreweries that have started using some of these new varieties, like the Pioneer craft brewery in the town center of Zatec.
MIKO HAVRDA: It's a small brewhouse. We have three vessels.
BARTON: Miko Havrda is the owner and brew master of Pioneer. He brews with both Saaz Comfort and Saaz Shine. And he says they make good beer.
HAVRDA: The Saaz Comfort has a little bit stronger and sharper bitterness than the Saaz Original. And the Saaz Shine is more fruity with some different red berries and some citrus, you know?
BARTON: He also still brews with the Saaz Original. But this year, his suppliers already told him they won't have as many hops. So he recognizes how important this research is.
HAVRDA: It is something what is necessary for the future to breeded these new varieties because of the climate change.
BARTON: And it's not just Czech brewers who have taken notice of these hops. Some American craft breweries are also using them.
BROCK WAGNER: The Saaz Shine hops are really the first new drought-tolerant hop that we've really been excited about.
BARTON: Brock Wagner is the founder of Saint Arnold Brewing in Houston, Texas. They've had a Czech lager made with Saaz Shine hops on tap at their beer garden since 2024.
WAGNER: It's definitely popular with our customers, especially the ones who appreciate traditional Czech lagers.
BARTON: Back at the Hop Institute, researchers hope that with rising global temperatures, these new hop varieties can keep Czech beer lovers happy for years to come.
For NPR News, I'm Katerina Barton in Zatec, Czech Republic.
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