Check the Label Before Buying Canned Tomatoes — This Ingredient Can Ruin Your Sauce

You might think fresh is always better than canned when it comes to fruits and vegetables, but there are some exceptions. One of those comes when you're cooking with tomatoes.

Because tomatoes can be picked at their very ripest and then stored and shipped worldwide without damage, chefs and many home cooks tend to prefer canned tomatoes for everything from a quick weeknight marinara to a rich Sunday sauce . 

But not all cans are created equal. Some contain extra ingredients that can work against you, especially if you're trying to cook those tomatoes down into a sauce. One to avoid: calcium chloride. If you see it listed as an ingredient, there are good reasons to put that can back and look for another.

Related: The Only Tomato You Should Use for Sauce, According to Chefs

What is calcium chloride, and why do tomatoes use it?

Chemically, calcium chloride is a type of salt. It's similar to table salt (aka sodium chloride). Despite the name, however, it doesn't provide any nutritional calcium. 

Calcium chloride is used in a variety of ways, including to deice roads. Industrial canning companies use small amounts to keep certain foods — including tomatoes, pickles, tofu, peppers, and tomatoes — firm.

"Calcium ions interact with pectin in the tomato cell walls, forming calcium-pectin crosslinks that help the tomatoes retain their shape during the high-temperature canning process," says Kit L. Yam , PhD, a professor in the Department of Food Science at Rutgers University. "This [can be] particularly desirable for products such as diced tomatoes, where maintaining the integrity of the pieces is important."

Why you should avoid calcium chloride in canned tomatoes

Unfortunately, as Yam notes, "the same strengthening effect also makes tomato tissue more resistant to breakdown during cooking." 

So when you're using those tomatoes to make a homemade marinara or a creamy tomato soup , calcium chloride will keep the tomato flesh firmer and chunkier than you want.

There are other reasons to avoid calcium chloride, too.

PJ Monte, owner of Monte's Fine Foods , whose jarred tomato sauce was F&W's favorite in a massive taste test, explains that calcium chloride in the ingredients list is an indication that the tomatoes aren't the highest quality.

Related: 5 Canned Tomatoes Chefs Always Keep in Their Pantries

"A good tomato doesn't need [it] or any preservatives. The tomato should have a low-enough pH and good texture all by itself," he says. 

But "if you've got a [subpar] tomato that was plucked at 90°F, then it sits overnight at the bottom of a pile on the back of a truck...would you want to eat that tomato? No. That's when you need those preservatives." 

There are a wide variety of canned tomato products on the shelves, from whole peeled all the way to tomato paste. While all of these categories are available without any firming agents, some are more likely to contain it.

Related: 16 Ways to Use Tomato Paste, From Tomato Bisque to Shakshuka

In general, you're likely to find calcium chloride in cans where tomatoes have some structure, including whole peeled, diced, crushed, and stewed. Cans of tomato puree, paste, and sauce are much less likely to contain the ingredient, but it's still always worth reading the label. 

How to pick superior canned tomatoes

No matter what you're using canned tomatoes for, Monte suggests sticking with whole peeled tomatoes the majority of the time, as they tend to be of higher quality.

"When I was doing the research [for my jarred sauce], I deep-dived into the research on this," he says. "We proudly use canned tomatoes in our recipes, and we're very picky about where we get them from. This is because 90% of the flavor [of a sauce] is in the tomato." 

What Monte discovered was that tomatoes are typically rated in the field, and those ratings determine what kind of can the tomatoes end up in.

Related: The $3 Store-Bought Shortcut I Use for Breakfast, Lunch, and Dinner

"The whole peeled tomatoes are generally the best: the ripest, the freshest, and the best-looking," he says. "Your A-tier tomatoes go in those cans. Then there's the B- and C-tier tomatoes. They've maybe got some blemishes. They're a little less nice looking. Maybe they're a little under- or overripe. Those go into the crushed or diced cans," he says. 

After that, anything that's salvageable goes into the even more highly processed cans, ending at tomato paste. So if you're looking for the highest-quality tomatoes for your sauces, stick with the least-processed cans with the fewest ingredients — ideally just tomatoes.

As for where to get them? Monte says it's worth experimenting. 

While a lot of people focus on San Marzano, Monte notes the extreme popularity has led to a lot of mislabeling and other issues. "California tomatoes are great — they're more plentiful and I believe are often better than what you can get elsewhere," he says. "But there are plenty of great tomatoes out there. I've seen canned cherry tomatoes, and delicious canned varieties of all types. Experiment. Have fun."

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