Heat one cup of sauce with a 1/4-teaspoon baking soda. Baking soda neutralizes acidity. Taste the sauce, add tiny amounts of baking soda to see if it mellows the acidity. If there is still an edge, swirl in a teaspoon of butter, letting it melt until creamy.
How do you take the bitterness out of spaghetti sauce? The acidity of the tomatoes can make spaghetti sauce taste bitter. Adding a couple of teaspoons of sugar to the sauce counteracts this acidity and gets rid of the bitter taste in the sauce.