The humble can of diced tomatoes: a pantry staple for home cooks and professional chefs alike. It’s a convenient, affordable, and readily available ingredient that forms the base for countless recipes, from hearty stews and flavorful pasta sauces to zesty salsas and comforting chili. But have you ever stopped to wonder exactly what kind of tomatoes are lurking inside that can? The answer isn’t always as straightforward as you might think.
The Tomato Varieties Commonly Used
While there’s no single, universally mandated “diced tomato tomato,” certain varieties are favored by producers for their characteristics that lend themselves well to canning. These choices are driven by factors like yield, disease resistance, texture, flavor, and processing suitability. Understanding these factors is key to deciphering what’s likely inside your can.
Roma Tomatoes: The Industry Standard
The Roma tomato is arguably the most prevalent variety used in canned diced tomatoes. These tomatoes are prized for their elongated shape, firm flesh, relatively low water content, and naturally sweet flavor. Their dense structure allows them to hold their shape well during the canning process, preventing them from turning into a mushy mess. The Roma’s meaty texture also contributes to a more substantial mouthfeel in the finished product. Moreover, Roma tomatoes are generally disease-resistant and high-yielding, making them a cost-effective choice for large-scale production.
Other Plum Tomato Varieties
While Roma tomatoes dominate, other plum tomato varieties, sharing similar characteristics, also find their way into canned diced tomatoes. These varieties, often bred for improved traits like disease resistance or higher yields in specific growing regions, offer subtle variations in flavor and texture. The general characteristics remain: a meaty, low-moisture tomato perfect for processing. These varieties may be proprietary to particular seed companies.
Round Tomatoes (Less Common)
While plum tomatoes reign supreme in the diced tomato kingdom, round tomatoes can sometimes be part of the mix. However, they’re less common due to their higher water content and tendency to soften more during canning. When round tomatoes are used, they are typically combined with plum varieties to achieve a desired balance of flavor and texture.
The Canning Process and Its Impact
The canning process itself has a significant impact on the final product, regardless of the tomato variety used. Understanding these processes helps to determine what qualities are being enhanced or diminished during preparation.
Harvesting and Preparation
Tomatoes destined for canning are typically harvested when fully ripe, ensuring maximum flavor and sweetness. Once harvested, they are thoroughly washed, sorted, and inspected to remove any damaged or unsuitable fruit. The tomatoes are then peeled, either through steam peeling or chemical peeling (lye treatment), before being diced into uniform pieces.
The Role of Calcium Chloride
A crucial ingredient in most canned diced tomatoes is calcium chloride. This salt helps to maintain the firmness of the tomato pieces during the canning process, preventing them from becoming overly soft or mushy. Without calcium chloride, the high heat and pressure of canning would break down the tomato’s cell walls, resulting in a less desirable texture. While calcium chloride is safe for consumption, some consumers prefer to avoid it, seeking out brands that offer “no calcium chloride” options.
The Importance of Tomato Juice and Purée
Canned diced tomatoes are typically packed in tomato juice or purée. This liquid serves several purposes: it helps to preserve the tomatoes, enhance their flavor, and provide a consistent texture. The juice or purée is usually made from the same type of tomatoes used for the diced pieces, although sometimes a blend of different varieties may be used to achieve a specific flavor profile.
The Heat Treatment and Preservation
The canning process involves heating the tomatoes to a high temperature to kill any bacteria and create a vacuum seal. This process ensures the product’s safety and extends its shelf life. The heat treatment can also affect the tomatoes’ flavor and texture, making them softer and slightly sweeter.
Decoding the Label: What to Look For
The product label offers valuable clues about the tomatoes in your can. Scrutinizing the ingredient list and product descriptions can shed light on the specific varieties and processes used.
The Ingredient List: Beyond Tomatoes
The ingredient list will reveal more than just the presence of tomatoes. Look for ingredients like calcium chloride, tomato juice, tomato purée, salt, and citric acid (used as an acidulant to maintain pH levels). The order of ingredients indicates their relative proportion in the product.
“Vine-Ripened” vs. “Field-Ripened”
Some labels may boast “vine-ripened” tomatoes. While this sounds appealing, it doesn’t necessarily guarantee a superior product. “Field-ripened” tomatoes, harvested at their peak of maturity, can be just as flavorful. The key is that the tomatoes are allowed to ripen fully before harvesting, regardless of whether they’re still on the vine or in the field.
Organic vs. Conventional
Choosing organic canned diced tomatoes ensures that the tomatoes were grown without synthetic pesticides or fertilizers. This is a personal choice based on dietary preferences and concerns about environmental impact.
“No Salt Added” or “Low Sodium”
If you’re watching your sodium intake, opt for “no salt added” or “low sodium” varieties. These options allow you to control the amount of salt in your recipes.
Flavor Variations and Regional Differences
The flavor of canned diced tomatoes can vary depending on the tomato variety, growing region, and processing techniques. Exploring different brands and regional variations can enhance your culinary experiences.
San Marzano Tomatoes: A Premium Option
San Marzano tomatoes, grown in the volcanic soil near Mount Vesuvius in Italy, are considered by many to be the gold standard for canned tomatoes. They are known for their sweet, intense flavor, meaty texture, and low acidity. San Marzano tomatoes are typically more expensive than other varieties, but their exceptional quality makes them a worthwhile splurge for discerning cooks. When buying San Marzano tomatoes, ensure they are certified “DOP” (Denominazione di Origine Protetta), which guarantees their authenticity and origin.
Growing Regions and Their Impact
The climate and soil conditions of the growing region can significantly impact the flavor of tomatoes. For example, tomatoes grown in California’s sunny valleys may have a different flavor profile than those grown in the cooler climates of the Pacific Northwest.
Seasoning and Added Flavors
Some canned diced tomatoes are seasoned with herbs, spices, or other flavorings. These additions can add depth and complexity to your dishes, but be sure to check the ingredient list to ensure they align with your taste preferences. Common additions include basil, oregano, garlic, and chili peppers.
Using Canned Diced Tomatoes in Recipes
Canned diced tomatoes are incredibly versatile and can be used in a wide range of recipes. Here are some tips for maximizing their flavor and texture in your cooking:
Sautéing Before Use
Sautéing canned diced tomatoes with onions, garlic, and other aromatics before adding them to your dish can enhance their flavor and reduce their acidity.
Draining Excess Liquid
If you prefer a thicker consistency, drain off some of the excess liquid before adding the tomatoes to your recipe. You can reserve the liquid for use in soups or sauces.
Adjusting Seasoning
Canned diced tomatoes are typically seasoned with salt, but you may need to adjust the seasoning to your liking, depending on the recipe. Taste as you go and add salt, pepper, or other spices as needed.
Adding Acidity
If your dish tastes bland, try adding a splash of vinegar or lemon juice to brighten the flavors. The acidity will also help to balance the sweetness of the tomatoes.
In conclusion, the tomatoes found in a can of diced tomatoes are most likely Roma or other plum varieties, selected for their texture, flavor, and suitability for processing. While the canning process alters the tomatoes, adding ingredients like calcium chloride, and using varying qualities like San Marzano, the end result is a versatile and indispensable ingredient in the kitchen. Paying attention to labels and understanding the process allows cooks to make informed choices and maximize the potential of this pantry staple.
What types of tomatoes are typically used in canned diced tomatoes?
Canned diced tomatoes usually feature varieties specifically bred for processing. These varieties are generally firmer, have thicker walls, and possess less juice compared to fresh market tomatoes. They are chosen for their ability to withstand the canning process without becoming mushy and for their uniform shape and size when diced. Common varieties include Roma, UC82, and other similar plum-type tomatoes that offer a consistent product after processing.
The exact tomato variety used can vary depending on the brand, region, and seasonal availability. However, processors prioritize varieties with high solids content and low acidity. This ensures that the final product maintains its texture and flavor profile throughout its shelf life. Often, the specific varieties used are proprietary or blend of different varieties to achieve the desired consistency and taste.
Are the tomatoes in canned diced tomatoes always ripe when processed?
Yes, the tomatoes used in canned diced tomatoes are ideally fully ripe when processed. Ripeness is crucial for achieving the desired flavor, color, and texture. Tomatoes harvested at their peak ripeness contribute to a sweeter, richer flavor profile in the canned product. Processors closely monitor ripeness levels to ensure optimal quality. However, they also need to balance this with firmness to withstand processing without becoming too soft.
To control the ripeness, tomatoes may be harvested slightly under-ripe and allowed to ripen further under controlled conditions. This allows for better management of the process and ensures a consistent supply of tomatoes with the right characteristics. The timing of harvesting and processing is meticulously planned to maximize flavor and minimize spoilage.
How are canned diced tomatoes processed to ensure their safety and shelf life?
Canned diced tomatoes undergo a process that involves washing, sorting, dicing, and filling the tomatoes into cans. After the cans are filled, they are typically steamed or blanched briefly to remove air. Then a liquid, usually tomato juice or tomato puree, is added to cover the diced tomatoes.
The most critical step is the heat sterilization process. The sealed cans are heated to a high temperature under pressure to kill any harmful microorganisms, particularly Clostridium botulinum, which can cause botulism. This sterilization process is what gives canned diced tomatoes their extended shelf life. After sterilization, the cans are rapidly cooled to prevent overcooking and preserve the texture and flavor of the tomatoes.
Do canned diced tomatoes contain any additives or preservatives?
Many brands of canned diced tomatoes contain minimal additives, often only calcium chloride. Calcium chloride is added as a firming agent to help the diced tomatoes retain their shape and prevent them from becoming mushy during the canning process. It is generally recognized as safe for consumption in the amounts used in canned tomatoes. Some brands may also include citric acid to adjust the acidity and maintain the color and flavor of the product.
However, some brands may include other additives such as salt, sugar, or flavor enhancers. It’s always best to check the ingredient list on the can to know exactly what is included. Look for brands that specifically state “no added salt” or “no added sugar” if you are concerned about these additives. Organic canned diced tomatoes generally avoid synthetic additives and preservatives.
Are there any nutritional differences between fresh and canned diced tomatoes?
Canned diced tomatoes are nutritionally comparable to fresh tomatoes. They retain most of the vitamins and minerals found in fresh tomatoes, including vitamin C, vitamin A, and potassium. The heat processing can actually increase the bioavailability of lycopene, a powerful antioxidant found in tomatoes. Lycopene has been linked to various health benefits, including a reduced risk of certain cancers.
However, the canning process can lead to some loss of water-soluble vitamins like vitamin C and some B vitamins. Salt content may be higher in canned tomatoes, especially if salt is added during processing. Comparing the nutritional information of different brands allows you to choose a product that best fits your dietary needs. Draining and rinsing canned tomatoes can also reduce sodium content.
Can I use canned diced tomatoes interchangeably with fresh tomatoes in recipes?
In many recipes, canned diced tomatoes can be used as a convenient substitute for fresh tomatoes. They work well in sauces, soups, stews, and casseroles where the fresh tomato flavor is desired but the exact texture of fresh tomatoes is not critical. Canned diced tomatoes can save time and effort in preparation, especially when fresh tomatoes are not in season or readily available.
However, the flavor and texture differences should be considered. Canned tomatoes have a cooked flavor and are generally softer than fresh tomatoes. If a recipe calls for raw fresh tomatoes, such as in a salad or salsa, canned diced tomatoes are not a suitable substitute. Also, consider the amount of liquid in the recipe, as canned diced tomatoes contain liquid that may need to be adjusted for in the recipe.
How should I store canned diced tomatoes after opening?
Once a can of diced tomatoes is opened, it is important to store any unused portion properly to maintain its quality and prevent spoilage. Transfer the leftover tomatoes to an airtight container. Glass or food-grade plastic containers are ideal choices to prevent the tomatoes from absorbing any off-flavors from the container itself. Seal the container tightly to minimize exposure to air.
Refrigerate the diced tomatoes promptly after opening, ideally within two hours. Properly stored, opened canned diced tomatoes can be safely stored in the refrigerator for up to 5-7 days. Discard any leftover tomatoes that show signs of spoilage, such as mold growth, an off odor, or a slimy texture. Freezing the tomatoes is also an option for longer storage, although the texture may change upon thawing.