Runny spaghetti sauce doesn't coat the pasta, resulting in a less-than-appetizing dish. To thicken a soupy sauce, you can either cook it down or add thickening agents to it. Cooking the sauce down takes time and should be done over low heat to avoid scorching the sauce. Adding thickening ingredients takes less time, but you must add the right ingredients to keep the sauce tasting as it should.
To thicken a tomato-based sauce, allow it to slowly cook in an uncovered pot over low heat. Excess liquid evaporates as the sauce simmers, leaving a thicker sauce over time. You can speed things up by adding a tablespoon of tomato paste at a time into the simmering sauce, stirring until it's incorporated. Be sure to taste the sauce before each addition, because too much tomato paste can make the sauce acidic and overwhelm the flavor of the herbs in the sauce.
White and Other Sauces
White spaghetti sauce, or salsa di besciamella, starts with a roux of butter and flour, stretched with hot milk. A higher flour and butter-to-milk ratio, such as 3 tablespoons each of butter and flour to 1 cup of milk, should make the sauce thick. To thicken a runny sauce, add more flour or even instant tapioca, or stir in cream cheese, heavy cream, grated cheese or cooked ground beef to absorb some of the excess liquid. The best way to thicken a sauce is to cook it longer, but be especially careful with a white sauce, as it can catch on the bottom and burn more easily.
- The Complete Book of Sauces; Sallie Y Williams
- Food and Wine: Classic Marinara Sauce
- Saveur: Besciamella (Italian-Style Béchamel Sauce)
- Pasta: Recipes From the Kitchen of the American Academy in Rome, Rome Sustainable Food Project; Christopher Boswell, et al
- Food Lover's Companion; Sharon Tyler Herbst
- Photo Credit olgna/iStock/Getty Images