The primary ingredient in a balsamic vinaigrette is balsamic vinegar. This type of vinegar originates from Italy and is made from the juice of freshly crushed grapes, which is then cooked down to create a concentrated syrup. It has a rich, sweet flavor profile that complements the acidity of the vinegar. Balsamic vinaigrette typically combines this vinegar with oil (usually olive oil), and may include additional ingredients such as mustard, honey, garlic, or herbs to enhance the flavor. It is commonly used as a dressing for salads, marinades, and drizzles over various dishes.