Almost no one remembers to buy tomato paste. It’s one of those pantry items that you take for granted, assuming that there will always be a few cans hidden somewhere in the deepest recesses of your cabinetry. You think you have tomato paste, but then, right when you need it, you discover that it’s gone.
Unfortunately, there is no blanket replacement for tomato paste, because it all depends on what you’re using it for. Tomatoes are naturally high in glutamates, so when reduced down into a paste you end up with a burgundy-colored umami concentrate that can add a big wallop of savory flavor to anything you’re making. It can instantly give soups, stews, and sauces a “simmered all day long” taste that most of us don’t have the time to achieve, or add a certain X-factor to sautés, sandwiches, salad dressings—pretty much all the “S” foods.
I recommend buying your tomato paste in a squeezable tube that you can keep in the refrigerator, not only because it keeps for a while, but it’ll remind you to use this magical ingredient more often. (Mutti is a good brand, found here, but it is by no means the only worthwhile one.) Play around with it, adding a tablespoon or two to anything you’re making that could use a nice savory bump. But if you don’t have a handy tube in the fridge, or if you’re reading this because you need immediate help and Google told you to read this, here are some substitutions that can work in a pinch:
If you’ve got some crushed tomatoes (these are good) or tomato puree (aka strained tomatoes), you can make your own paste in 20 minutes or less. Multiply the paste measurement given in your recipe by five, then pour that amount of canned tomato into a small saucepan. Bring it up to a boil and then drop it down to a simmer, stirring every minute or two to keep it from scorching. (In addition to glutamates, tomatoes also have a lot of natural sugars that will burn if you allow them to stick to the bottom of the pan.)
Once it’s reduced to a fifth of its original volume, you’ll have made your own tomato paste—but now you’ve got a half used can of tomatoes you have nothing to do with. This is why I recommend using this method if you’re making some sort of tomato-based sauce, or a big pot of something that needs a good amount of simmering, like soup or chili. Just go ahead and dump the whole can in there to reduce, because dishes like these really don’t need tight measurements. A little extra tomato paste really can only make things taste even better than your original recipe.
If all you want to add to your dish is splash of savoriness, grab one of these pantry staples. Neither has the sweetness that tomato paste brings to the party, but when it comes to umami few things compare to fish sauce. Other good substitutes in this vein: Maggi Sauce (a great seasoning sauce), Vegemite (which you can buy in eco-friendly packaging), anchovy paste, or a smidgen of mushroom soup base (available here). None of these things can be replace tomato paste measure for measure, and all are extremely intense, so add just a bit and taste as you go.
Umami might not be the reason you’re reaching for tomato paste; sometimes you’re looking for a luscious and slightly sweet background note, like in a pan sauce or a quick sauté. A well-mashed roasted red pepper works great in this sort of situation, but personally I like using spicy, fragrant harissa, which is on my Top 10 Condiments list. What are the other nine? A real lady never tells all.
When someone asked me whether ketchup could be used as a tomato paste substitute, I initially said no—ketchup is not a pure tomato puree, but a mixture of tomatoes, vinegar, sugar, spices, and a bunch of other fun stuff. Then I asked this person what sorts of things they normally use tomato paste for, and when they said goulash, I changed my mind. It’s still not a perfect substitution, but in dishes heavy on strong, smoky spices like paprika, ketchup’s sugar can help round out some the spices’ aggressiveness, which, incredibly, can actually make them taste like better versions of themselves. So while ketchup isn’t your best substitute for everything, if whatever you’re making uses a generous amount of spices like cumin, chipotle, or liquid smoke, try adding a bit of ketchup and see how you like it.