With St Patrick’s Day this week, millions of Americans are raising a glass. Beer remains the country’s most popular alcoholic drink with more than 6bn gallons consumed each year. But from water shortages to rising temperatures, the climate crisis is putting pressure on beer’s most essential ingredients.

At Deschutes Brewery in Bend, Oregon, beer is either stacked high in warehouse rows or racing down a canning line and assembled into 12-packs. Inside the cavernous cellars, enormous 6,000-gallon tanks hold the latest batches in progress.

But inside one of those tanks, something unusual is brewing.

The secret ingredient is a grain called Kernza. It’s a perennial wheatgrass with a slightly nutty flavor and a climate-friendly reputation. Deschutes teamed up with outdoor clothing brand Patagonia to craft a new beer using the grain.

When asked how customers react, brewer Ben Kehs laughs: “They say what’s Kernza?”

Kernza has deep roots that pull carbon from the atmosphere and require less water. There is less tilling and fuel use because it doesn’t have to be replanted each year. Kernza can be used as an alternative to barley, which along with hops and water, is one of beer’s three core ingredients.

“All of them in one degree or another I would say,” Kehs explains when asked which ingredients face climate threats.

Those sobering threats include drought, extreme heat and wildfires.

Nowhere is that clearer than in the Pacific Northwest, where roughly 75% of the country’s hops are grown. Hops are the delicate flowers that give beer its flavor and aroma. They are especially sensitive to changing conditions.

In Washington state’s Yakima Valley, Ryan Christian oversees hops research at Yakima Chief Hops, a grower-owned global hops supplier. Asked whether beer’s future depends on hops, Christian doesn’t hesitate: “Hops are integral to beer so absolutely.”

But growing hops here during hot, dry summers depends on irrigation fed by snowmelt from the Cascade Mountains. As the climate warms, spring snowpack is rapidly declining. Scientists project it could drop 75% by the end of the century, threatening a critical water source for farmers.

“This is now heading into a potential fourth year of consecutive drought that hasn’t happened in the past,” Christian says. “Drought is normal. The frequency is abnormal.”

In the lab at Yakima Chief Ranches, researchers are racing to develop drought- and disease-tolerant hop varieties, hoping innovation can keep pace with a changing climate.

From experimental grains like Kernza to hardier hop varieties, brewers and farmers are adapting in real time trying to protect the future of the US’s favorite pour.

Climate Central is an independent group of scientists and communicators who research and report the facts about our changing climate and how it affects people’s lives.