Somerville duo Spot Collins’ album, Birch Beer is a stripped-down collection of folk-punk songs. The “punk” label may not be so apparent at first in the face of Spot Collins’ quiet, acoustic sound. But listen to the evocative lyrics, listen to the little twists going against the folk norm. Each song tells a single, encapsulated story, many of them presenting glimpses of life as a musician, especially “Jackie O. In Heat” or “Pretty Girl at the Punk Rock Show.” The simple, sparse instrumentals leave the spotlight on the raw, plaintive vocal line, adding to the overall intimate nature of the album. Overall, Birch Beer sounds weary, but happy, like someone picked up a guitar in the living room as the party’s winding down.