Successfully Canning Tomato Sauce

Since my Mother's tomato sauce always separated, I grew up wondering how commercially canned tomato sauce was so perfectly homogeneous. What was their secret?

Considering that my best guesses were way off mark, it is a good thing that we have books to educate us. My best lesson in preventing separation, came form the Ball Complete Book of Home Preserving. I can't figure out why the Ball Blue Book doesn't pass this advice on.


Any way, to understand separation, lets talk about the way my mother did it. She would quarter a huge kettle full of tomatoes, then put it on the stove to cook. The whole time that she was standing there quartering tomatoes, the air was interacting with an enzyme in the tomatoes and breaking down the pectin in the tomatoes.

In commercial production, the whole tomatoes are flash heated. The heat deactivates this enzyme. At this point, it doesn't matter if the insides of the tomato get exposed to air, because the enzyme has already been deactivated.

Since we don't have the equipment to flash heat foods at home, does this mean that there is no hope for home canned tomato sauce? Well, I can't promise perfect tomato sauce, but I can offer advice to increase your chances.

Quarter just a few tomatoes, turn the heat on and smash them with a potato masher. Quarter a few more, add them to the pot, and smash them too. Stir the pot every time you add more tomatoes. Since you only cut a few tomatoes at a time, the cut surface is only exposed to air for a very short time before it gets heated.

When you have them all cut up simmer your tomatoes for about 5 minutes, then run them through your food mill.