When you simmer a tomato sauce for hours, the flavor intensifies and becomes deeper due to a combination of factors, not just because it's being reduced. The long cooking time allows various chemical reactions to take place, enhancing the flavors and transforming the sauce's overall taste. Here are the main reasons why the flavor intensifies:
Concentration: As the sauce simmers for an extended period, some of the water content evaporates, resulting in a thicker and more concentrated sauce. This reduction in liquid means the flavors become more pronounced and robust.
Caramelization and Maillard Reaction: When you cook the tomato sauce for a long time, the natural sugars in the tomatoes and other ingredients start to caramelize, creating deeper and richer flavors. Additionally, the Maillard reaction occurs between amino acids and sugars, contributing to the sauce's complex and savory taste.
Breakdown of Ingredients: The prolonged cooking time breaks down the vegetables, meat (if included), and herbs in the sauce. This breakdown releases more of their flavors and allows them to meld together harmoniously.
Flavor Infusion: The extended cooking time gives the herbs and spices more time to infuse their flavors into the sauce, making it more aromatic and flavorful.
Acid Reduction: Tomatoes are naturally acidic, and long simmering helps to mellow out the acidity, resulting in a smoother and well-balanced sauce.
Overall, it's the combination of concentration, caramelization, breakdown of ingredients, flavor infusion, and acid reduction that makes a tomato sauce taste deeper and more flavorful after hours of simmering. However, it's essential to strike a balance, as excessive cooking can also cause the flavors to become overly concentrated or even lose some of their original freshness.