Czech Scientists Breed Drought-Resistant Hops to Save Iconic Pilsner
Drought-Resistant Hops Developed to Protect Czech Pilsner

It is the country that drinks more beer per capita than any other, but in recent years Czechia has been hit by droughts and heatwaves, making it harder to grow Saaz hops, a key ingredient in its world-famous pilsner. At the Hop Research Institute, scientists are working to create new, climate-resilient hop varieties that show promise in overcoming both the heat and the country's strict traditionalism.

"I see a very bright future for Czech hops," said Dr. Vladimir Nesvadba, the institute's top breeder. "We have bred new drought-resistant varieties – Saaz Shine, Saaz Comfort, and others – that are performing well on hop farms and in Czech breweries."

Global Demand for Saaz Hops

The reputation of Saaz hops extends well beyond Europe, with roughly 80% of Czechia's Saaz yields going to breweries abroad. The US brewery BarrieHaus Beer Co in Tampa, Florida, imports them for its Czech-style pilsner called "Bublina," which won the 2024 World Beer Cup. Their brewmaster, Jim Barrie, says Saaz "has a character that's difficult to truly replicate."

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Climate Impact on Hop Production

However, in recent years, summer temperatures have risen and rainfall has decreased in Czechia, particularly affecting the Saaz variety. This reduces water availability and makes it harder for plants to stay cool. According to Dr. Pavel Donner, also of the Hop Research Institute, "Czech cultivars, Czech genetic resources, are not habituated to live in such high temperatures."

Only about 25% of Czech hop farms are irrigated, making them highly vulnerable to irregular rainfall. Higher temperatures and lack of water result not only in fewer cones but also less alpha acid, the compound that gives hops their characteristic bitterness. With less acid, brewers need to use more hops to achieve the same bitterness, altering the flavor. This variation creates challenges for brewers who rely on consistent expectations for their yearly hop orders.

According to Barrie, the droughts and higher temperatures have made BarrieHaus's Bublina harder to produce. "We've definitely seen more year-to-year variation in alpha acid levels, aroma intensity, and overall availability, especially with drought pressure in Czechia. For example, I haven't seen a Saaz varietal over 2.5% in years," he said, referring to lower alpha acid levels in drought-afflicted hops. "This last crop of Saaz was the least appealing sensory-wise since we opened in 2019."

That change in quality, along with lower yields, may explain why imports of Czech hops to the US dropped by roughly half after a particularly brutal drought in 2022.

Current Season Risks

The stakes are especially high this year, as Czechia enters the hop-growing season during the driest spring since record-keeping began in 1961. "We don't know what's coming," said Donner. "The estimations can be made in June or July. Until then we just depend on the weather."

Breeding New Varieties

This is why Nesvadba's breeding work is so important. Working with home brewers to test new hop cultivars, he has created three varieties based on the original Saaz hop that can thrive with less water and higher temperatures. Earlier this month, Nesvadba unveiled a new lager crafted using his "Saaz Shine" variety at the Hákův brewery's pub in Prague. An hour before the keg-tapping, dozens of craft-beer enthusiasts crowded in, eager to try the new cultivar. As Nesvadba proudly held up the first glass of the drought-resistant brew in the dimly lit basement bar, the crowd burst into applause and began to line up to fill their own mugs. The event illustrated the excitement for novel varieties even in Czechia, which takes its beer tradition seriously.

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The new varieties are also encouraging innovation in places that have never had a hop industry. Sardinian agronomist Federico Puddu spent a month working closely with Nesvadba to learn techniques for creating new breeds of native Sardinian hops to grow on his home island – a place typically considered far too hot and dry for hops. "A lot of people say to me that I am crazy," said Puddu. "The usual question is: 'How can you even think about hops in Sardinia, in that heat?' But the point is that heat and drought are becoming a problem for hops everywhere." Puddu believes these new varieties present an exciting opportunity for hops not only to adapt to climate change but also to expand hop agronomy to new regions.

Nesvadba's work is also exciting for brewers like Barrie, who seek consistency in their product but are not attached to a particular cultivar. "There's a lot of innovation happening with growers, who are currently developing more drought-resistant and climate-resilient hop varieties," said Barrie. "Hopefully these new varieties will be as appealing as the highly sought-after classic varieties like Saaz."

Yet however far these new varieties travel, even their creator believes the original Saaz is not going anywhere. "The new Saaz Shine and Comfort varieties will never replace the original Saaz," Nesvadba said. "Saaz is our gold."