Everything You Need To Know About Canned Tomatoes, Ever
The season of braising and carbo-loading is upon us! And so we begin the transition from luscious farmers' market tomatoes to the canned variety, but fret not — this is no reason to sulk. Tomatoes destined for a can are picked and processed at peak ripeness, preserving all the texture and flavor you expect from a high-quality vegetable. Given the diversity of types and preparations available, canned tomatoes are a versatile addition to any cooking repertoire, particularly in the fall as temperatures drop and hearty dishes like stews and pastas demand rich tomato bases.
Here's everything you need to know (and then some) to be well equipped for a productive stroll through the preserved tomato section. Choose your cans wisely, but more importantly, choose with gusto! And a little data and some diligent kitchen experimentation, of course.
General Points
All canned tomatoes are comprised of two tomato varieties: standard garden vine tomatoes and plum tomatoes. Better-quality canned tomatoes will specify the kind of tomato used, but for those that don't or those that employ a nondescript qualifier, like the elusive "Italian-style tomato," it's safe to assume they are one of these two primary types. As a best practice, I don't buy cans that don't identify the tomato used. I also veer away from anything preseasoned — I want full control over the product, which won't happen with predetermined basil and oregano content.
The structural fortitude of plum tomatoes makes them ideal for canning. They are meaty and contain less juice and fewer seeds, which means they'll maintain their shape in the can. Garden vine will hold up nearly as well, but have a different flavor profile and totally different shape. If you're interested in canning at home, other tomatoes are perfectly good substitutes, but in general you want to use what is referred to as a "paste tomato," meaning one with the qualities mentioned above to ensure they don't deteriorate over time.
Below is a breakdown of common canned tomato preparations available at the market. All canned tomatoes are cooked (they actually cook in the can during the sterilization process), with a few limited exceptions. Try to select cans with the furthest expiration date, meaning they've been canned more recently. Prolonged exposure to the aluminum is what causes tomatoes to adopt a "tinny" taste (the acid from the tomatoes interacts with the inner lining of the can).
On San Marzano
The Holy Grail of canned tomatoes, but imposters are rife. The San Marzano tomato is a specific genus of plum tomato native to the Agro Sarnese-Nocerino region of Italy. It has a particularly thin skin and a meaty, pithy interior, soyou get a full-flavor vegetable that isn't watery, which makes the San Marzano excellent for canning. It has a unique tangy sweetness other tomatoes can lack, making it a popular choice for pizza sauce where the balance of tangy and sweet is integral.
It carries a denominazione di origine protetta ("DOP"), or a protected designation of origin — a kind of legal protection to ensure that certain food products have specific, unique characteristics wholly dependent on the territory in which they are produced. To be a true San Marzano tomato, it must come from this territory and carry the DOP certification.
However, like numerous other great Italian products, San Marzano tomatoes are currently grown all over the world, including California, where the climate is prime given the tomato's delicate skin. Much like grapes in Napa, however, just because you can grow a San Marzano tomato outside of Italy doesn't mean it will taste the same. Terroir, mode of harvesting and preparation and processing of the tomato for canning are key factors in delivering an authentic San Marzano tomato. They also are only sold whole, so if you see a can of pureed San Marzanos, know that those tomatoes are not from Italy.
Whole: San Marzano (D.O.P.)
$5-7.00/28-ounce can
A luxury price for a luxury tomato. The oblong shape is unique to the variety and much more pronounced than that of a basic plum. They're extremely soft and velvety in texture, delicate and tender. There is a deep mellowness to the flavor of the tomato juice. These tomatoes would be excellent for sauce — the delicate composition is ideal for hand-crushing for a quick, super-fresh sauce or a slow-simmering sauce that would allow whole tomatoes to slowly break down and build depth of flavor over time.
Whole: San Marzano (origin: United States)
$4-4.50/28-ounce can
A worthy imposter. These tomatoes have the smoothest peeled exterior of all the whole tomatoes and lack the "fuzzy" appearance of some of the others. Their shape is similar to a large kiwi fruit or a stretched-out golf ball. Because they aren't as tender as authentic San Marzanos, they maintain their spherical shape very well. All tomatoes in this can are fully intact. There is a generous amount of juice with rich viscosity. If you refuse to splurge on a $7 can, this is an admirable replacement.
Whole: basic plum (organic)
$3.50-$4.25/28-ounce can
A refined option. Larger than San Marzanos, they hold up to canning very well; however, there is a faint "fuzzy" texture around the tomatoes, likely from the pith's prolonged exposure to liquid. Ideal for at-home crushing or dicing before incorporating into a chili or stew. These won't have the same inherent flavor complexity of San Marzanos, but will perform laudably in a well-seasoned sauce when allowed to simmer and reduce to develop full flavor. These would also be a great choice for a braise, so the tomatoes can meld with the protein and collagen to build flavor.
Whole: unspecified
$1.50/28-ounce can
The workhorse of tomatoes. The exact tomato type is unclear, but I suspect most brands use vine ripe based on shape and color and the larger, visible veins in the tomato exterior pith. Given the cost, these are great multi-purpose tomatoes to use as building blocks where tomato is not the focus of the dish. I suggest combining with stock to create a tomato-scented liquid for risotto. Or drain the liquid and roast the tomatoes whole on a baking sheet to intensify flavor before adding to sauces or casseroles.
Diced
The last resort. I rarely purchase diced tomatoes in a can. The dice is almost always uneven, and because there is so much surface area exposed to the liquid, I find the tomatoes are mushy and start to prematurely break down in the can. They are ideal for one thing, however: chili. They absorb all the spices while they cook, but maintain enough of their texture that the result is little pockets of warm, chili-soaked tomato goodness.
Crushed
The clutch player. If you're looking for a time-saver, I recommend buying crushed. The texture will reduce down in a sauce in less time than whole or diced, and result in a velvety-rich texture. Depending on the brand, the blend can range in viscosity, but a properly crushed can of tomatoes will resemble cocktail sauce that's heavy on the horseradish. Imagine a thick applesauce: not chunky, but not pureed like baby food, either. If you can find a brand that uses New Jersey vine tomatoes (or a faux San Marzano brand), buy with confidence. I've been impressed with the super-fresh flavor and even consistency of both. In fact, these are the default canned tomatoes in my own kitchen.
Stewed
Fast-forward two steps ahead: Stewed tomatoes are boiled completely and mixed with onions, green bell peppers and other seasonings before being canned. Depending on the brand, they come either diced or halved, but I found that most brands halve their stewed tomatoes. Because of the spices added, stewed tomatoes are a great addition to casseroles, bean soups and certain Latin American or Creole recipes that use similar flavor profiles. Just beware of the halves, which will require a longer cooking time.
Purees, passatas, strains and sauces are relatively the same in terms of consistency. They all pass through a thinning application (strainer, mill, etc.) to achieve a sauce-like texture. Generally, they descend in viscosity with purees being the thickest and sauces being the thinnest. The primary differentiating factor among them is whether the tomatoes are seasoned and/or cooked and how thoroughly they are sieved.
Puree
The key to a proper puree is sieving. After the tomatoes are cooked, they are passed through a fine sieve to remove seeds and achieve an even texture. Consistency can vary depending on brand and how much moisture they retain in their mixture, but I prefer a puree of a medium-heavy viscosity that holds little mounds when I move it with a spoon. Since the tomato is being so heavily processed, I recommend buying a higher-quality brand for puree — you're already losing textural complexity, so aim for maximum flavor by buying a brand that clearly uses plum tomatoes. Or buy whole San Marzano and puree yourself at home in a blender or food processor. Be sure to seed them first, as pulverizing the seeds can add a bitter flavor.
Passata
Passata is essentially an uncooked tomato puree; however, most brands label their passatas as "passata/puree," suggesting that they are one and the same. A true passata is raw and packaged in a glass bottle instead of a can to avoid the acid-aluminum interaction that taints fresh tomato flavor. They also have a much shorter shelf life (two days after opening) in light of the raw contents. I'm a little skeptical that jarred passatas are actually raw, as that sounds like a food safety violation to me, but I'll let it slide. Treat passata like you would a puree: a great shortcut toward a super-smooth pizza sauce or marinara.
Strained
Strained tomatoes can be more difficult to find than their more popular counterpart, pureed tomatoes. For a proper strained product, the tomatoes are peeled, seeded, and cooked and their liquid separated before the tomatoes are sieved, ensuring an even consistency free of any pith or seeds. It also usually means a very thin but very smooth final product, since the straining process breaks down the tomato more than sieving. I've only found strained tomatoes packaged in a BPA-free box, which makes them easily pourable and storable.
Sauce
In many ways, sauce is the most manipulated canned tomato option. In addition to heavily processing the tomatoes into a thin puree, the mixture is also seasoned. Tomato sauce is typically a combination of puree/passata and strained tomato and/or tomato juice, with added spices like basil, oregano, and garlic. Sauces vary wildly based on the brand and their seasoning decisions. As a general rule, if you must buy canned sauce, opt for a high-quality brand and be sure to incorporate it into a dish with other layers of flavor and additional rounds of cooking. I would never recommend pouring plain sauce out of a can onto a pizza crust, for example.
Paste
Tomato paste is a concentrate made from reducing tomato pulp (skins and seeds removed). It is the most flavorful option of all shelf-stable tomato options and is used in very small quantities to give a powerful, tomato-y umami depth to a dish. If making a braise or ragout, I recommend caramelizing about two tablespoons of paste with well-sautéed mirepox before deglazing and/or adding a canned tomato option from the above list. It will give the dish a depth of tomato flavor not achievable with canned (or fresh) tomatoes alone, no matter how long you reduce them.