Vermouth is a fortified wine that is often enjoyed as an aperitif in Madrid. It is made by infusing wine with various botanicals, such as herbs, spices, and roots, and then fortified with a spirit, usually brandy. Vermouth can be enjoyed on its own, over ice, or as part of a cocktail, such as a Negroni or Martini. It is a versatile and flavorful drink that is perfect for starting a meal or enjoying a leisurely afternoon in Sol Madrid.