Differences between canned and fresh tomatoes

Question

I read on the web (including here) that canned tomatoes are usually more suitable for tomato sauces (in particular pizza sauce) than fresh tomatoes. It is unquestionable that both are really different, but What makes them so different ? Canned tomatoes aren't supposed to be baked already, or are they ?

I'm thinking it may have to do with the maceration in tomato juice, in which case one should be able to achieve similar results by making jars of fresh tomatoes. Another possible (partial) cause could be that tomatoes are much more mature than fresh tomatoes a normal human would pick.

Of course I'm assuming we are considering similar tomato varieties (e.g. Roma, I guess).

Answer 1

Canned tomatoes, compared to fresh, are:

• Cooked. As part of the canning process, they are fully cooked.
• Peeled. Most canned tomatoes are peeled
• Acidic. For safety reasons, canned tomatoes often have additional citric acid added to the can (this prevents botulism growth)
• Ripe. The tomatoes to be canned are often vine ripened to a more ideal ripeness than retail tomatoes, and then immediately harvested, processed and canned.

Most of these attributes are actually an advantage in creating a pizza sauce, and so starting with a quality canned tomato may be far more convenient and flavorful than starting with raw tomatoes.

Answer 2

It's really a matter of time, and cost. You can make a great tomato sauce with fresh tomatoes, and it will beat anything you get out of a can. However, you need a whole load of very good tomatoes, and lots of time and effort to scald them, peel them, then cook them down until they thicken. It's not worth making a tomato sauce out of mediocre tomatoes, you'll spend a lot of time on a bland sauce, so depending on where you are and the time of year it's an expensive proposition.

Good canned tomatoes are picked at the peak of ripeness and then immediately used, sometimes they are partially processed before they even leave the field. Store bought tomatoes are picked before they are at their peak (most are still green!) and then artificially ripened after they are transported, which is why you can get tomatoes all through the year but mostly they taste like cardboard. So the ones you get in the can are probably better than the ones you can buy. This is why I grow my own, they aren't that much work and there's nothing better in the world.

If you can get really good tomatoes and can afford to do so then by all means make your own sauce from scratch as it does taste different from canned, generally fresher and less acidic. If that's not an option buy the best quality canned tomatoes you can get afford, they will be very tasty and they are instantly ready.

Answer 3

Most canned tomatoes are processed so that the natural pectin is locked in. This helps keep the shape, but is no good if you want to make a thick sauce. That's why most recipes using canned tomatoes also use tomato paste. The paste supplies available pectin. You don't need to worry about any of this with garden tomatoes.