What cocktail ingredient is known for adding bitterness and complexity?

Bitters are uniquely characterized as a concentrated flavoring agent that adds complexity and depth to cocktails. They are typically made by infusing various herbs, spices, roots, and other botanicals in alcohol, creating a rich flavor profile that enhances the overall taste of a drink. In cocktail crafting, bitters serve not just to introduce bitterness, but also to balance sweetness and acidity, providing a more nuanced and sophisticated drinking experience.

For instance, classic cocktails like the Old Fashioned or Manhattan rely heavily on bitters to achieve their signature taste. The bitterness can help cut through sweetness, highlighting other flavors in the drink, and leading to a well-rounded and enjoyable flavor experience. In contrast, sugar primarily adds sweetness, fruit juice offers sourness and sweetness, and club soda provides carbonation without adding any complex flavor elements. Therefore, bitters are essential for bartenders aiming to create balanced and intricate cocktails.