Vermouth is a fortified wine that is flavored with various botanicals, such as herbs, spices, and roots. It is commonly enjoyed as an aperitif in Barcelona, either on its own or mixed with soda water or tonic. Vermouth can be dry or sweet, and it has a complex flavor profile that can include notes of bitter herbs, citrus, and caramel. It is often served with a slice of orange or a sprig of fresh herbs.