In a saucepan, you can choose to sauté minced garlic and grated ginger in a small amount of oil over medium heat until fragrant. This step adds depth of flavor to the sauce.
In a separate bowl, whisk together the granulated sugar, white vinegar, ketchup, and water until well combined. This mixture forms the base of your sweet and sour sauce.
In the saucepan with the sautéed aromatics (if used), pour the sugar-vinegar-ketchup-water mixture. Heat the sauce over medium-high heat, stirring constantly.
As the sauce thickens, you can adjust its consistency by adding more water if needed. To achieve your desired balance of sweetness and tanginess, you can tweak the sugar and vinegar quantities at this stage.
For an extra layer of flavor, incorporate soy sauce into the sauce, stirring it in until well combined. The soy sauce contributes a hint of umami and richness.
Allow the sweet and sour sauce to simmer gently for a few minutes, stirring frequently, until it reaches your desired consistency. The sauce should become glossy and coat the back of a spoon.
If desired, garnish your sweet and sour sauce with chopped scallions for a burst of freshness and color. Your homemade sweet and sour sauce is now ready to be served!