BEIJING — Ice might just seem to be ice.
But not in curling.
The frozen sheets created for elite competitions like the Olympics are the product of a painstaking process under the direction of a team of specialists hewing to the particular demands of ensuring a heavy stone, aided by the furious sweeping of a broom, glides gracefully down a track.
Even in the best of conditions, in facilities constructed for the sport, the job is a stressful one. In Beijing, it has been a whole other story.
The world’s experts on creating ice worthy of Olympic-class curling were handed a challenge more daunting than anything they had faced: Turn an Olympic-size swimming pool in the National Aquatics Center into lanes of ice ready for the world’s best curlers.
“It’s never really been done before,” said Hans R. Wuthrich, the chief ice technician for the Beijing Games, his fourth Olympics and just one of many elite competitions in his decades-long career.
Chinese officials have boasted about Beijing’s status as the only city that has hosted both the Summer and Winter Games — a feat achieved, in part, by recycling venues built for the 2008 Olympics.
Curling events are in the natatorium with the honeycomb exterior, which was known in 2008 as the Water Cube and where Michael Phelps won eight gold medals for the United States. For the Winter Games, it has been rechristened as the Ice Cube. But getting it ready was hardly as simple as changing its name.
A first challenge was to construct the infrastructure to hold up the ice. The pool was filled with a metal scaffolding system topped by a layer of concrete.
Then came making the ice — and an early obstacle: The Cube’s tap water had a reading of 375 parts per million of total dissolved solids, like salts, minerals and ions. That amount is acceptable for drinking water, but freeze it, and it’s still not good enough to curl on. The impurities affect the ability to make the sheets as flat as they can be.
The team used filtration systems to clear the water. But by the time they were done, it was too pure for human consumption.
“If you actually drank it,” Mark Callan, the deputy ice technician for the curling events, said, “it would burn your insides.”
Outside, water freezes from the top down, creating a surface that is wildly inconsistent. Inside, “you’ve got to go very slowly,” Callan said, “and allow it to freeze the water from the bottom up.”
Once the upper layers freeze, white paint, logos and other markings are added. In all, the ice is 10 centimeters thick, or nearly four inches.
The next hurdle was the air. The building was too dry — “which is a bit ironic,” Callan said, “being we’re in a swimming pool.”
The team installed a system of humidifiers releasing a constant mist around the periphery of the ice. That still wasn’t enough. Wuthrich took pride in the solution: filling a smaller pool not far from the ice with hot water. “Everyone thinks we are absolutely crazy,” he said in a post on Twitter, along with a photograph showing it off.
Even after the ice is frozen to their specifications, the technicians continue fussing over details, monitoring the ice and the atmosphere around it at a granular level: too warm, too cold, too much moisture, too little moisture, not enough texture for the stone to glide. Any deviation can have an outsize impact on the competition.
“We work within a thousandth of an inch of accuracy,” Wuthrich said after his team finished the ice for a round of women’s matches.
The precision of the work contradicts a notion that as far as Olympic sports go, curling is easy. The sport is widely accessible, and in amateur clubs, participants go for a beer and a good time.
But at the Olympic level, it is driven by athleticism and strategy, and the ability to read and know the ice is a key to winning. As much as the brooms and the stones, it is about the ice.
“It’s a game of skill, not a game of chance,” Callan said. “So if you can’t provide consistent conditions, then you start to negate the skill level, and it becomes more of a game of chance — and it’s our job to make sure that’s not the case.”
Wuthrich and Callan — along with a third ice technician, Shawn Olesen — were drawn to this niche career by a passion for curling. They have day jobs. Wuthrich, who lives in Manitoba, owns a landscaping company and nursery; Callan, who lives in Glasgow, Scotland, is the director of sales for the company that makes the stones used in elite curling events by mining granite from an island off Scotland.
As much as they find the work satisfying, they also acknowledge the pressure that comes with it.
“It’s the pinnacle of everything, and as an ice maker, it’s the same thing,” Wuthrich said of the Olympics. “You’ve got to be on your toes all the time. If any little thing happens, you have to fix it. You have to make it the best possible because people tried for 20 years to get to this event.”
One night, before the day’s last round of games, the three technicians — along with a crew of nearly two dozen Chinese volunteers, most of them college students — went through their ice preparation routine.
The crew used an ice scraper to even out the lanes. Callan wore a backpack with a canister of water and a sprayer that looked like a shower head. Strutting backward on the lanes, he sprayed droplets of water to create the texture that allows the stones to move across the flat surface and spin.
Then they took out a contraption called a rock mover, which allowed them to rake a line of curling stones across the ice to simulate play. They want the ice to be broken in for the players.
In a final step, Callan went out with a single stone and tested it. Under the terms of their contract, they have to provide ice on which a stone can move four to five feet in 24 to 25 seconds. They aim to keep the surface temperature of the ice at roughly 23 degrees Fahrenheit.
The days are long and getting longer. They arrived in Beijing a month ago, and there have been over a dozen days of competition, with as many as three rounds of games per day. On the job, Wuthrich walks about 10 kilometers a day; because he does the texture pebbling, Callan gets in 12 kilometers.
They start each morning at 6. Lately, problems have kept creeping up, meaning they are often working until 1 a.m.
On Monday night, as the South Korea women’s team was working toward a 5-point lead over Japan, Wuthrich walked away from the ice and sat back for a moment. He imagined himself home in Manitoba, his two black Labrador retrievers nestled on either side of him. He savored the thought, but went back inside, where the curlers were deep in competition, strategizing and shouting.
His eyes were on the ice.