Canned tomatoes nearly always taste better than fresh, except possibly in the month of August, when fresh tomatoes peak in ripeness and flavor. Because canned tomatoes get picked at the perfect moment and immediately processed, they maintain the sweet taste and balanced acidity of a perfectly vine-ripe tomato, making them the best choice for both year-round enjoyment and everyday convenience.
Roma vs. San Marzano
Roma tomatoes and San Marzano tomatoes are two varieties of plum tomatoes, the most common type grown for canning. San Marzano tomatoes must be cultivated and harvested in the Agro Sarnese-Nocerino region of Italy near Mt. Vesuvius and similarly to Italian wines, true San Marzanos bear the D.O.P. mark confirming their origin. Roma tomatoes grow worldwide but California produces 95 percent of the commercial crop in the United States. Some plum tomatoes grown in the U.S. may be sold as "San Marzano-style" tomatoes; though they are not true San Marzano tomatoes, which must be grown in Italy, they are similarly sweet with low acidity, a pulpy texture, and few seeds.
Whole peeled tomatoes undergo minimal heating, usually just the quick burst of steam necessary to remove the skins. They may be packed in tomato juice or purée. From whole peeled tomatoes, processors also produce various cuts.
Uncooked varieties include diced tomatoes, which range from medium to small chunks, and crushed tomatoes, which get ground into a coarser consistency. The cans generally contain seeds.
Canned tomato purée has been cooked and strained, so it's free of seeds. Tomato paste comes from simmering the purée to remove as much as 80 percent of the water content. Tomato sauce includes seasonings, usually salt and sugar but sometimes herbs and garlic as well.
Stewed whole tomatoes have been cooked and seasoned with salt, sugar, and other ingredients such as celery, bell peppers, onions, herbs, and spices. Cooks who prefer a greater degree of control over how much and what kinds of seasonings go into their sauce may want to make this from scratch. However, the canned product can be a real time-saver.
Canned Tomato Uses
Most folks find that tomatoes packed in juice offer a fresher, fruitier flavor. Marinara sauce benefits from this fresh, clean tomato flavor, so recipes generally start with whole tomatoes in juice.
Whole peeled tomatoes and diced tomatoes usually contain calcium chloride, which helps keep them firm. However, dicing exposes more surface area, so diced tomatoes absorb more calcium chloride than whole tomatoes, which means they don't break down easily when you simmer them. Choose whole tomatoes for long-simmered sauces. Use diced tomatoes when you want the pieces to keep their shapes, such as in soups, chunky sauces, chilis, and stews.
Crushed tomatoes also provide a good base for pasta sauce. Since they don't need to hold their shape, they are free of calcium chloride and will cook down to a smoother consistency than diced tomatoes.
Some brands of tomato purée are in fact tomato paste reconstituted with water, which tends to separate when you heat it. Since you can't tell from the packaging, this might not be a good choice of canned tomato product when you can easily purée a can of whole or crushed tomatoes on your own.
Canned tomatoes are not a good substitute for fresh, however, when you want to use them raw, such as in a salad or uncooked salsa, or on a sandwich.
How to Cook With Canned Tomatoes
You can start with whole canned tomatoes for practically any cooking use. For sauce, purée them yourself in a blender or food processor or simply break them up with a wooden spoon while they simmer. You can also dice them or crush them, and add seasonings to your personal taste. Either leave the seeds or strain the tomatoes through a metal sieve to remove them.
If you do start with whole tomatoes, you may want to look for cans without calcium chloride for smoother sauces and purées, or opt for already crushed ones, which generally do not contain it.
The other forms of canned tomatoes add convenience, but you do pay a bit more for the additional processing.
In most applications, you can get better results if you strain and reserve the packing liquid (juice or purée), then give the tomatoes a few turns in the pot to cook off any excess moisture before you add the liquid ingredients. For example, if you build a soup base by softening diced onions, carrots, and celery in a sauté pan, you could add drained chopped or crushed tomatoes for the final few minutes.
What Do They Taste Like?
The quality of canned tomatoes can vary, but if you choose good brands, they should taste sweet with a touch of acidity. Do note, however, that canned tomatoes do not taste particularly appealing straight out of the can. They tend to be watery with a raw flavor, which is not the same thing as fresh.
Canned Tomato Substitute
You can use fresh tomatoes, but the quality of your sauce may suffer unless you find fully ripe and tasty ones. Many supermarket tomatoes get picked too early so they can survive the trip to the store; tomatoes soften but do not continue to ripen or develop flavor off the vine. In general, you need a pound of fresh roma tomatoes for each 14.5-ounce can of diced or crushed tomatoes in your recipe. You do need to peel them before you use them, and if your recipe calls for tomato paste or stewed tomatoes, you need to cook them before you add them.
Canned Tomato Recipes
Canned tomatoes are a convenient, economical, versatile pantry staple. Find a brand you like and keep them stocked so you can make a quick meal or a saucy side.
Where to Buy Canned Tomatoes
Nearly every food store in the country carries canned tomatoes. You can find them in the standard tin can (look for ones marked BPA-free), in Tetra cartons, and in glass jars. They are widely available from online grocery retailers as well, and available in cases from both bulk stores and standard grocers.
Canned tomatoes generally last for a year or longer past the best by date, if you store them in a cool, dark pantry and the can shows no signs of damage. Once opened, canned tomatoes should be transferred to an airtight container, refrigerated, and used within five to seven days. You can also freeze them for longer storage; for best quality, use them within three months.
Many recipes call for a small amount of tomato paste, leaving you with an open container. Spoon it out by tablespoon onto a piece of parchment and freeze the lumps, then store them in a plastic bag until another recipe calls for it.
Nutrition and Benefits
The nutrition content of canned tomatoes will vary depending on the style and any added seasonings, sugar, and other ingredients. A 1/2-cup serving of plain diced tomatoes contains 22 calories, 10.3 percent daily value of potassium, and 1 gram of protein. Tomatoes also deliver some calcium and iron. They are a good source of the antioxidant lycopene, which has been linked to better heart health and a lowered risk of certain cancers. However, canned tomatoes generally contain sodium as a preservative, often in significant quantities, so check labels and opt for low-sodium varieties.