Jeff beachbum berry is the godfather of the modern tiki revival, a mixological indiana jones who travels around the globe to unearth and document long-lost tiki recipes. When noted tiki-mug sculptor bosko hrnjak designed a mug in beachbums honor, beachbum himself christened it with an all-new recipe: the beachbums own. The original recipe calls for demerara rum, a usually-dark style known for its burnt-sugar flavors and complex nose. A regular dark rum will do if thats all you have, but if you plan to make more drinks like beachbums own, a good guyanese demerara rum is a worthy investment for your liquor cabinet. Passion fruit puree is ideal, but if you cant get your hands on that, passion fruit syrup will do. If you do opt to use syrup, try it first with a little bit less than called for in the recipe below, since it is generally sweeter than a puree.