Xiaolongbao are traditionally filled with pork. More modern innovations include other meats, seafood, shrimp, crab meat, and vegetarian fillings. Soup dumplings are created by wrapping solid meat aspic inside the skin alongside the meat filling. Heat from steaming then melts the gelatin-gelled aspic into soup. In modern times, refrigeration has made the process of making tangbao during hot weather easier, since making gelled aspic is much more difficult at room temperature.