For more than a century, Chicago’s been known as the “Candy Capital of the World,” with treats such as Snickers, Tootsie Rolls, and Milk Duds making their way from the kitchens of local family-run businesses to candy counters everywhere. This documentary spotlights another homegrown confection, Lanzi’s Cashew Nut Crunch. Developed by Elmo Lanzi, an Italian immigrant who built his candy company (machines and all) from the ground up, Lanzi’s Cashew Nut & Rice Crunch drew an international cult following before disappearing from shelves in the mid-80s after Lanzi’s closed shop. When an entrepreneur expressed interest in rebooting the candy, Lanzi’s grandson, the award-winning Chicago filmmaker Michael Lahey, was inspired to document his journey while exploring his family’s history and delving deep into the city’s sweetest industry. Anyone whose relatives came to the U.S. to pursue the American dream could relate to the Lanzis (and who wouldn’t want grandparents like Elmo and Helen?), but Lahey balances their tale with science, commerce, and of course, candy, to make Shelf Life more than just a touching family story.