– When Larry Kortuem gives a presentation about life in a log cabin, he can talk about the experiences of pioneers a ­century and half ago.

Or he can talk about his own.

"Since I've got it warmed up, I might stay tonight," said Kortuem, standing on a recent winter night in the 148-year-old cabin built by his great-grandfather, immigrant pioneer Bernard Kortuem.

Larry Kortuem had been stoking a fire in the large wood-burning stove, and the one-room cabin was comfortable despite the winter's day on the other side of the oak logs. The open loft where Kortuem would sleep, as did Bernard's 10-member family in the 1870s, was downright toasty as the stove's heat rose upward.

Still, Kortuem's wife, Trixie, made clear her husband would be sleeping alone. "I'll come in the summer," she said.

Both Kortuems are interested in the history of their rural Madison Lake community and in the immaculately restored cabin that was the seedbed of a Kortuem clan that spread across southern Minnesota and beyond.

He wonders how much in peril that bountiful crop of descendants might have been in the earliest days. Bernard, a German immigrant who first lived in Michigan, is believed to have arrived in rural Madison Lake in 1867 with his wife, Francesca, their first four children and all of their possessions in a wagon drawn by a pair of oxen.

They spent their first winter in a hole dug in the side of a hill. The cabin was constructed in 1868. It's a large home by pioneer standards, and it needed to be: Bernard and Francesca soon would share it with eight children.

While Bernard spoke only German when he arrived, he was Roman Catholic and appeared to have gotten along well with the Irish Catholics who preceded him in the Marysburg community west of Madison Lake.

There are no journals or letters from Bernard to provide clues to his family's experience in those early years. He was likely illiterate, not to mention overwhelmed by work, so the only information comes from scattered government and church records and a bit of oral history passed down through the generations.

That's part of the reason Kortuem spends time in the cabin, including on nights when temperatures dropped to 10 to 20 below and on hot summer days. Living in the same building as did his great-grandfather, his grandfather and great-aunts and -uncles — even if it's just a day here or there — provides a visceral connection to history that supplements his research on pioneer life.

His conclusion?

"The practicalities of living in a log cabin are a whole lot different from the b.s. they put in the movies," he said.

He knows, for instance, that on a windy subzero winter night it's nearly impossible to keep the indoor temperature above 50 degrees, even when feeding the stove as much wood as it can take. On typical January nights, the stove needs to be stoked every two or three hours to keep the temperature from plunging.

"You'd have to have a pile of wood about the size of this place to heat it through the winter," Kortuem said.

When a family Thanksgiving was held in the cabin in 2010, with six adults and eight grandchildren, they learned some lessons, too, about cabin life. "Thank God, the kids were outside a lot," Trixie Kortuem said. "I don't know how those people could take it."

And, during meal preparation, sending the kids up to the loft wouldn't work. Because when people tromp around up there, dust settles down on the food.

Sleeping 14 in the cabin, using both the main floor and the loft, they understood better the closeness of the quarters and how tuberculosis could spread from one child to the next, ultimately killing three of Bernard and Francesca's offspring.

Larry Kortuem guesses the 10 Kortuems also had some guests living with them most of those 19th-century winters. Farmers were so dependent on their seed supply that, fearing theft, they often kept it in the cabin over the winter, which undoubtedly attracted a variety of rodents. And the oxen would have been of such irreplaceable value that he wonders if they were invited into the cabin when temperatures got dangerously low.

Bernard lived in the cabin until 1915, when his wife died and he moved to Madison Lake.

Rather than being torn down, the cabin became the south wing of a new barn that year, large holes sawed into the north and south walls for cow doors. But even when the barn was torn down in the 1960s, Kortuem's father, Francis, didn't dismantle the cabin.