From the outside, the Napa Valley Olive Oil Company looks more like a ramshackle barn than a thriving business. Of course that’s the appeal of the St. Helena hot spot: While everything else in town has gussied up over the years, this place has remained true to its workmanlike roots. The Olive Oil Company has existed in the same spot since 1931; today the Particelli family owns and operates it as a full-fledged Italian grocery with cured meats, cheeses, breads, and more. As the name suggests, however, the main attraction is olive oil, and the company sells that by the jugful. All told, the place sells 20 different oils, each a blend of different olives, some including other flavors such as lemon, garlic, chili, and basil. The store sells 20 different balsamic vinegars as well.