The secret to bolognese is in that can of tomatoes in your pantry. But wait—which can, exactly? The San Marzanos or the stewed? Will crushed tomatoes do? And while we're at it, what is tomato puree, anyway?
Valid questions, all. I’ve pondered these at one time or another, usually while staring down the shelves in the canned goods section at the store.
For clarification, I called Beth Richwine, a spokeswoman for Indiana's Red Gold Tomatoes. While the differences between puree, paste and various other canned tomato products can seem subtle, they’re worth knowing. Your bolognese depends on it.
What’s in the can?
Tomatoes, salt, citric acid and calcium chloride, mostly.
Tomatoes are picked at their peak and processed in the can quickly, often within hours of harvest, Richwine said.
Citric acid keeps the acidity or pH at a safe level. It's naturally present in tomatoes, but more can be added in processing, Richwine said.
Calcium chloride, a natural firming agent, helps tomatoes, especially the diced varieties, maintain their shape.
No to dents, yes to dates
Avoid cans that are dented or bulging. At home, keep them in a cool, dry place.
And keep an eye on the "best by" date. That refers to peak flavor, not freshness. Canned tomatoes will be good a year past that date, Richwine said.
The rundown
Within these broad categories, you'll find even more variety—“fire-roasted,” Italian-style, green chilies added and so on. Texture and flavor also can vary between brands.
Whole peeled. The starting point for many a marinara, these come in puree or juice.
San Marzano. A specific variety of plum tomato grown in Italy's Argo Sarnese-Nocerino region, near Mount Vesuvius, often hailed as superior in flavor and texture than the rest and ideal for sauce. True San Marzanos are protected and regulated under Italian law and will have a D.O.P. seal denoting this. Check the labels; some might say "San Marzano-style," which isn't the same.
Diced. These are firm—and stay firm—during cooking. Good for long-simmered dishes where you want distinct tomato pieces.
Crushed. Crushed to a fine texture and often mixed with a little tomato puree, but still chunkier and less cooked-tasting than sauce.
Puree. Pureed tomatoes that fall somewhere between crushed and paste—smoother, thicker and deeper in flavor than crushed, but not nearly as concentrated as paste.
Stewed. Whole or diced tomatoes cooked with seasonings and often sugar and thus even softer than regular whole peeled. Some cooks might appreciate the pre-seasoned flavor and stewed texture, others not so much.
Sauce. Pureed tomatoes with added seasonings and sometimes water. Good as a base for soups, stews, casseroles.
Paste. The most concentrated form made by cooking down tomatoes and evaporating the liquid. A dab deepens the flavor of all sorts of dishes.
Storage options
Transfer any leftovers from an opened can to an airtight storage container. They'll keep refrigerated for about a week.
Canned tomatoes, if frozen, turn to mush once thawed. Tomato paste fares much better frozen.
