Time Out says
Frankfurt’s traditional apple wine culture can be experienced at taverns around the city. This is one of the oldest and best places to try it.
You can’t visit Frankfurt without sampling its famous Apfelwein (or Ebbelwoi, apple wine), available by the glass or Bembel (jug), pure or mixed with lemonade or soda water. Have a glass with dinner at one of Frankfurt’s oldest apple wine taverns, Zum Gemahlten Haus; if you’re feeling hungry and adventurous, try a mixed platter of local sausages, meats and Sauerkraut. If you’re vegetarian, choose the eggs with green sauce.