The Complete Handbook of Ketchup

Chapter 1: Understanding Ketchup

Ketchup is a stabilized tomato-based condiment engineered to remain uniform in texture, resist separation, and deliver consistent flavor and viscosity across a broad range of storage and use conditions. Unlike fresh tomato sauce, which is volatile and time-limited, ketchup is formulated and processed to achieve shelf stability and predictable performance. Understanding what ketchup is—and what it does—matters because those physical and chemical properties directly determine whether a specific product will perform as expected in your kitchen, production line, or supply chain.

At its foundation, ketchup is a mixture of tomato solids, vinegar, sugar, salt, and spices suspended and stabilized in a matrix that prevents the components from separating during storage. The tomato solids—the actual tomato material, not juice—form the body and color. Vinegar provides acidity, which both preserves the product and contributes flavor. Sugar balances that acidity and adds sweetness. Salt enhances flavor perception. Spices (typically onion, garlic, allspice, clove, and cinnamon) provide complexity. None of these are controversial or surprising. What matters is the proportions, the processing method that binds them, and the stabilizing agents used to prevent them from coming apart.

Federal standards and compositional requirements shape every ketchup you can legally buy in the United States. The FDA defines tomato ketchup in 21 CFR 155.194 with specific minimum and maximum requirements: finished ketchup must contain a minimum of 25 percent tomato solids by weight. That number is not arbitrary. It establishes a floor below which a product cannot claim to be ketchup; it