Substitute for Canned Tomatoes

Canned tomatoes are ripe tomatoes peeled, packed in their juice and heat-processed. They bring liquid, body, acidity and a cooked, consistent flavor that does not depend on the season. USDA data show tomatoes canned in juice at about 95 percent water, almost the same as fresh. So the swaps are mostly about weight and texture: how much of something else carries the same amount of tomato, and whether the dish should be chunky or smooth.

Sauces, soups and stews

Fresh tomatoes replace canned well in summer. The National Center for Home Food Preservation figures an average of 3 pounds of fresh tomatoes per canned quart, which works out to about 1¼ pounds for a 14.5-ounce can and 2½ pounds for a 28-ounce can. To peel them, cut a shallow X in the base, drop them into boiling water until the skin curls back, then into cold water. Simmer longer than with canned, since fresh tomatoes release more water and taste lighter.

Tomato sauce and tomato paste are concentrates, so they need water to stand in for a can. The amounts in the table come from USDA water figures: a cup of sauce or 5 tablespoons of paste carries roughly the same tomato solids as a 14.5-ounce can in juice. Salt is the catch. A cup of salted canned tomato sauce has more than twice the sodium of a whole can of tomatoes in juice, according to USDA data. Hold back salt until the end.

Chunky versus smooth

Diced and whole canned tomatoes give a chunky sauce; crushed tomatoes and passata give a smooth one. Mashing whole tomatoes in the pot makes a rustic texture in between. Diced canned tomatoes usually stay firm even after hours of simmering, because many brands add calcium chloride to firm them; check the label. Fresh tomatoes and crushed tomatoes collapse much sooner.

When not to substitute

For home canning, use only a tested recipe from the National Center for Home Food Preservation; do not substitute ingredients, change jar sizes or skip the added lemon juice or citric acid. Off-season fresh tomatoes are a poor swap in long-simmered winter sauces, where canned plum tomatoes have better flavor and color.

Common mistakes

• Using tomato sauce without water. The dish turns thick and too salty.
• Leaving skins on fresh tomatoes in a long-cooked sauce. They curl into tough strips.
• Expecting diced tomatoes to break down. Added calcium keeps them in cubes; use whole or crushed for a smooth sauce.
• Swapping by volume with fresh, whole tomatoes. Cut tomatoes pack differently; weigh them or count 4 to 5 medium per can.