Perhaps because the acidity is concentrated with the reduction of water. Beyond that I can't tell you.

The NCHFP recipe doesn't require lemon juice either and it even has added sweet red peppers.

There are differences in recipes, even from reliable sources. Some, for example, require lemon juice in applesauce and some don't. Ball Complete Book of Home Preserving yes, Ball Blue Book no.

Carol

Here is a link that might be useful: NCHFP Tomato Paste

That's the recipe I'm following. I wanted to be certain there wasn't an omission in the recipe! The jars are now in the canner! Thanks!

Jill

I've always shied away from canning cooked down tomatoes (wanted them for spaghetti sauce), because of the density problem (not wanting to add bottled lemon juice either). What's the difference here with tomato paste?

Bejay

It is because of water activity. Less water, less available to allow bacteria to grow.
Plus, it is packed in only half pint jars. The processing time is comparable to other tomato products, but you will notice the smaller jar size.

Bejay - What's the difference ph wise or density wise?

pH, like Carol said, is because of the markedly reduced amount of water. More water = higher pH.

The density issue is resolved by the much smaller jars and the much longer processing time 45 mins. for a half pint of paste vs. 35 mins. for a pint of sauce. And the fact that both are tested recipes.

Dave

I made this recipe today (from So Easy to Preserve), and omitted the red peppers, but otherwise followed the recipe to a tee. I was originally just going to freeze it, but am wondering if it is safe to can? Seems like it should be ok since it is am omission of a low-acid food, not an addition, but wanted to get opinions. Thanks!

I think anything from So Easy to Preserve is safe to can if you're using the most recent version and following the recipe.

I was having the same question. The Ball Complete book says to add 1/4 teaspoon citric acid (the usual amt for pints) to the 8 oz jars before adding the cooked down paste. So Easy to Preserve doesn't mention acid. So I have to decide whether I feel an abundance of caution is in order or not. They also differ on headspace, ball says 1/2 inch, sotp says 1/4 inch.

I don't know how you resolved your citric acid vs. no citric acid dilemma, but my suggestion is to just buy some and keep it dry in a jar, and use it whenever you are canning tomatoes or tomato juice because it has no taste when added in small quantities. It does provide a margin of safety, is really cheap, will last a long time if you buy 8 ounces or a pound, and it has no shelf life if you keep it dry.
Also, if you have some over-ripe fruit to can or over-ripe fruit for jam making, you can add a little citric acid to give the fruit a little "bite".
It is what they used in children's Gummy Bears and all such sweet sour candies to give them that tart taste.
Del Monte even adds citric acid to canned grapefruit sections - a fruit you may not think could benefit from citric acid.
Certain cheese calls for citric acid to acidify milk products. So it does have multiple uses.
Just my thoughts,
Jim in So Calif

The NCHFP recipe in the most recent edition of So Easy to Preserve calls for 8 quarts chopped tomatoes, 1 1/2 cups chopped red bell, some salt, some bay leaf, 1 clove garlic. (Garlic and bay leaves removed before processing.) No citric acid and 1/4" headspace.

So I wouldn't worry about the citric acid one way or the other. Add it if you like or not.

So Easy to Preserve is basically USDA; it doesn't get more reliable than that.

Carol