Spaghetti sauce, which is a generic term for a tomato sauce-based that is served with spaghetti noodles, can be made with either red or white wine, depending on the flavor profile the cook is trying to achieve. Dry red wine imparts a robust, deep flavor to spaghetti sauce while white wine adds a fruity flavor to the sauce.
Wine is generally added to tomato-based sauces, such as marinara, Bolognese or Sunday gravy, when the vegetables for the sauce are being sauteed. This allows the flavor to be absorbed while allowing the alcohol in the wine to cook off. Wine can also be added to the end of a sauce as a flavor enhancer and to thin out a sauce that may be too thick.