"I think of this round like a stretching of boundaries," Troitzsch said, asking the dozen or so sweat-covered people who filled the benches of the Hewing Hotel's rooftop sauna to push themselves to take the heat.

If 170 degrees was too much, you could to move to a lower bench or to the floor, he offered. Just don't open the door unless you really need to.

Then he poured another scoop of lavender- and rosemary-scented water onto the rocks, sending up a cloud of steam — and even more heat.

Troitzsch was leading an intense German wellness ritual called "aufguss."

This sauna experience combines high heat (like a Finnish sauna) with lots of steam (like a Russian banya), with some aromatherapy mixed in. It's guided (a bit like a yoga class) by a "sauna meister," who encourages you to stretch your limits of tolerance for heat and cold.

Uniquely German, aufguss is a more structured take on the Finnish tradition of using a sauna to relax with friends and family. But while it's new to Minnesota, it's already found fans, who gather several times a month to sweat together with Troitzsch and another meister, Karoline Lange.

"I really, really came to enjoy the aufguss experience because it's a guided steam experience and you get pushed a little bit," said Lange, a primary care doctor in the Twin Cities. "I then appreciated the rigidity of it, in the sense that it starts at this time, no one leaves, no one goes in and out. There are rules that you kind of have to acknowledge to make the experience really nice and meaningful."

Lange said she was intimidated when she first tried aufguss as a girl in her native Germany, where it's widespread at bathhouses and community saunas.

"Germans, they have a lot of rules, and I didn't know the rules," she said. "So there were these people telling me, 'You need to do this.' 'You can't do this.' 'Stop talking!' "

Soon, though, Lange ended up embracing the practice, which she compares to the more physical forms of yoga.

"You get to know your boundaries, and breathe into your boundaries," she said. "You're opening up a whole new realm of getting to know your body in ways that you haven't before."

Best of all, she said, is the feeling that you've put in a "super intense workout," without actually working out.

"You get the runners high, and you are super relaxed."

Showstopping sauna

Unlike many sauna traditions, aufguss (which means "infusion") isn't an ancient one. It started in the 1970s, and gradually spread throughout Europe, becoming especially popular in Switzerland and Italy.

It's grown to the point where there's now an Aufguss World Championship, where sauna meisters from different countries are judged on their towel twirling, their heat- distribution technique and their wow factor. Some turn the sweatbox into a stage, where they wear costumes and dance to music while they boost the steam and toss their towels like pizza dough in the air.

When Troitzsch was back in Germany for the holidays, he sat in on some wildly entertaining aufguss, which attract hundreds to oversized saunas.

"I was actually sitting in a sauna and they did an AC/DC aufguss, and they did, like, 'Highway to Hell,' " he said. "They don't call it a sauna anymore. They call it a sauna theater."

The aufguss sessions he leads at the Hewing in Minneapolis' North Loop are much tamer.

One of his recent sessions included three rounds of increasing heat, for each of which he applied different essential oils. In between each eight- to 12-minute round of heat, Troitzsch encouraged everyone to "embrace the cold," and draw in exhilarating breaths of winter air on the hotel's rooftop, which overlooks downtown.

Making new traditions

John Pederson has hosted saunas for several years, as the founder of the member-owned cooperative 612 Sauna Society. But he first heard about aufguss in 2014, when someone called him a sauna meister.

He wasn't sure what that meant.

"I was pleased to learn that, despite the pompous sound of the word to the English-speaking ear, it was meant as a compliment," Pederson said.

He quickly learned about aufguss and even tried to register for a training program, until he discovered that classes were offered only in German.

When he met Troitzsch and Lange (in a sauna, of course), he invited them to run sessions hosted at the Hewing and at the 612 society's mobile sauna, currently parked at the Loppet Trailhead in Theodore Wirth Park in Minneapolis.

Pederson said Minnesotans have embraced aufguss.

"One of the things I've learned from hosting thousands of sauna sessions is that many guests appreciate a little info and guidance that introduces some of the basic principles of hot-and-cold conditioning," he said. "Of course, if you grew up doing regular sauna, as most Finnish people do, this may seem unnecessary, and it probably is. But for those of us who didn't grow up with a regular thermic bathing practice of any kind, a little info and direction can help."

Aufguss does have critics, though. Some sauna-purist Finns have even trolled Pederson on Facebook, calling aufguss a "cancer of sauna culture."

For her part, Lange, who is tending steam this winter in 612's mobile sauna, sees a broadening of the sauna experience for Minnesotans.

"What I like about what the Sauna Society is doing now is that, yes, we're bringing in these different traditions. But we're also making them our own," she said. "I do think we're cultivating a new sauna society, a Minneapolis-style sauna. With Finnish roots and German roots, but there's space to do things and create new ideas and new traditions."

Erica Pearson • 612-673-4726

Steam emanated from the bodies of Tricia Sletten, standing center, and others fresh from the sauna during a cool-down on the roof of Minneapolis’ Hewing Hotel. (The Minnesota Star Tribune)