Substitute for Tomato Paste

Tomato paste is tomatoes cooked until most of the water is gone. USDA data put unsalted paste at about 74 percent water, against roughly 88 percent for purée and 91 percent for canned tomato sauce. That concentration is why a single spoonful can color and thicken a pot of chili and give it a deep, savory base without making it watery. Its other trick needs heat: fried in oil until it darkens to brick red, its sugars caramelize and the raw, tinny taste disappears.

Sauces, soups and braises

The best swap depends on how much water the dish can take. A soup, curry or braise already has plenty of liquid, so tomato purée or tomato sauce can go in unreduced: use 2 tablespoons of purée or 3 of sauce per tablespoon of paste and cut the stock or water by the difference. Those amounts follow the water figures above; purée has a little under half of paste’s solids and sauce about a third.

For a thick ragù, a pizza sauce or a curry base where water would thin everything out, reduce first. Simmer the purée or sauce in a wide pan, stirring, until it holds a trail when a spoon is pulled through it. Then fry it in oil as the recipe says to fry the paste.

Barbecue, chili and glazes

Ketchup is tomato concentrate with sugar, vinegar and salt, which is why NMSU Extension can list tomato sauce plus sugar and vinegar as a stand-in for it. In barbecue sauce, chili, meatloaf or a burger mix those extras belong, so ketchup works spoon for spoon. Taste before adding the recipe’s sugar or vinegar; it often needs less.

Uncooked uses

Paste in a dip, a pesto or a spread is eaten raw. Puréed sun-dried tomatoes suit these better than paste does, since their flavor is already concentrated and mellowed by drying.

When not to substitute

Where paste is the main thickener in a small volume, such as a pizza sauce made by thinning paste or a tomato glaze brushed onto meat, liquid swaps fail unless reduced all the way. Ketchup does not suit Italian, Indian or Middle Eastern sauces; its sweetness and vinegar show.

Common mistakes

• Adding unreduced sauce to a thick dish. A tablespoon of paste becomes three of liquid, and a stew turns soupy.
• Reducing over high heat. Sugars catch on the bottom of the pan and the sauce tastes burnt.
• Forgetting the salt in tomato sauce. Salted canned sauce plus the recipe’s own salt can oversalt the dish; season at the end.
• Skipping the frying step. Purée and sauce also taste raw unless cooked in oil until darker.