Last time I saw the Carolina Chocolate Drops at their home away from home in the Cedar Cultural Center, the temperature was bobbing on either side of zero and the trio from temperate Durham, N.C., was charming a hardy capacity crowd with guileless good humor.

The Drops play mountain string band music from the early 20th century, a mixture of Delta blues and pre-bluegrass fiddle and banjo picking that arose in the Piedmont region of the Carolinas. They’re young, came to the music late (formed in April 2005), and don’t pretend otherwise. But they learned the style from one of the last remaining pioneers, Joe Thompson, and have been diligent in their fidelity to the authentic sound he played and preached.

There’s no denying that their live show has a whiff of shtick to it. They take the stage in simple cotton garb that fits the bohemian tenor of college kids, but also the dress of the era. They bounce and weave as they strum their strings, huff and puff on their jugs and forge vocal harmonies that are by turns plaintive and upbeat, forlorn and full of piety.

But the music and the attitude are the product of true believers, earnest in the best sense of the word. It’s homemade artistry, like a quilt, peach cobbler, or tongue-in-groove carpentry with wooden dowels. There is a performing history of blues, square dances and Celtic music in their roots, giving them a natural proclivity for coaxing shy audiences into relaxing its defenses. Here’s a great extended performance from NPR’s “Mountain Stage” series — skip the first two minutes of vocal intro and dive into the tunes.

The lone woman, Rhiannon Giddens, is the most charismatic, the unofficial MC at center stage. Tall, lanky Dom Flemons provides a fair share of comic relief, and Justin Robinson is the all-purpose glue. When they launch into the sway and swirl of a gem like “Rickett’s Hornpipe,” as they do here, it is impossible to stand still.

Carolina Chocolate Drops at the Cedar Cultural Centre, Saturday, March 28, at 8 p.m. and Sunday, March 29, at 7:30 p.m. Tickets are $17 in advance and $20 day of show.