There are a few different reasons why your sauce doesn’t have the flavor you’d hoped for. The tomatoes might have picked up a metallic bitterness during canning or during the course of your cooking time. You might have burdened the sauce with too many flavoring ingredients or scorched it on the bottom of your pot. Alternatively, it might have an acidic bitterness that leaves the flavors unbalanced. You can address all those issues, either during preparation – the proverbial ounce of prevention – or as a desperate “save” after the sauce is finished.

Fixing a Finished Sauce

If you’ve already made your sauce and it’s too late to start over, you’ll have to try a few tweaks to make it more palatable. First, taste it again and ask yourself what the problem likely is. If there’s a hint of a burnt taste, move the sauce to a new pot and lower the heat before you do anything else. If you see dark, stuck-on sauce, it was likely the culprit.

If your sauce has a bitterly metallic taste or if it just seems as if too much is going on and the flavors are muddy, the most-effective fix is to cheat. Add a jar or two of commercial sauce, which will dilute the unpleasant flavors of your own. Another option is to add heavy whipping cream to the finished sauce, making it a “rose” style rather than a pure tomato sauce. The cream both enriches and mutes the flavors, and finishing each bowl with a generous handful of grated cheese will help mask any remaining bitterness.

Adding salt or sugar to the finished sauce may also help mask “off flavors.” If the sauce is too acidic, a pinch of baking soda, well stirred in, will neutralize the acidity. If it’s flabby and lacks acidity – or if you’ve overdone the baking soda – a splash of wine vinegar or lemon juice can help brighten it. A small amount of savory, umami-rich ingredients such as anchovy paste, soy sauce, Worcestershire sauce or Asian fish sauce can also help. It’s not as far-fetched as it seems: The Romans used similar fish sauces, so it has deep roots in Italian cookery.

Avoiding Bitter Flavors Through Good Technique

It’s much easier and more effective to make your tomato sauce properly in the first place, which mostly comes down to good basic technique. One of the first things you should do – it’s hammered into the head of every would-be chef during training – is taste everything. If your tomatoes are bitter, your sauce will be bitter as well. You can rinse the tomatoes and remove the seeds and stem ends to reduce the bitterness if you don’t have the opportunity to buy more.

If your recipe calls for tomato paste, don’t add it right into the sauce. Tomato paste often has a metallic taste, but you can change that by frying it first in a bit of oil until it browns, caramelizes and mellows. Keep tasting it as you go, but eventually, your nose will tell you it’s done. It will start to smell oddly sweet, at which point you can add it to your sauce.

Unless your sauce is specifically meant to cook quickly, low and slow cooking is usually the better bet. That gives the flavors plenty of time to meld and get acquainted, and cooking it this way makes it unlikely you’ll burn the sauce. Spices and dried herbs should go in at the early stages. Fresh herbs should go in just before you eat, so their flavors remain bright. If they’re added too soon, they’ll become bitter.

Use Non-Reactive Cookware

The pot you choose to cook your tomato sauce in matters, too. Cast iron and aluminum are both excellent metals for cookware, but both will react with the acidity in a tomato sauce. That doesn’t mean you can’t use them, but they’re best suited for quick-cooking sauces, and you shouldn’t cool or store the sauce in the pan. They’ll react chemically with the acid in the tomatoes and give the sauce an unpleasant flavor or color.

Your better bet is to use stainless steel or enameled cookware or stove-safe glass or ceramics if you have them. These materials don’t react with acidity, so they can’t transfer any unwelcome flavors to your finished sauce. The earthenware liner of your slow cooker is another non-reactive surface, and slow cookers are a great option for cooking tomato sauce. They’re designed for exactly this kind of low, slow cooking, and there’s little-to-no risk of your sauce burning. Just remember to leave the lid off or slightly ajar so moisture can evaporate, and the sauce can thicken and become naturally concentrated.