Canning tomato sauce, research and frustration

Ever since I started making our own tomato sauce I’ve wanted to can it instead of freezing it (like I do).  And yes, technically you can, safely, can tomato puree.  But the approved as safe recipes all tell you to add extra acid to the mix for safety.  Since part of why we like our homemade sauce is the low acid this didn’t appeal to me.  What I’ve never quite understood is why they tell you to add acid to the pressure canned version too.  After all the whole point of the pressure canner is to do LOW acid stuff.

So this week I emailed the National Center for Home Food Preservation to find out WHY they tell you to add acid to the pressure canned version.  The response was that the listed pressure canner version is just the equivalent of the water bath method (for folks who prefer to pressure can), not a low acid, safe from botulism, method.  Personally if I can safely water bath can it I’m going to do that rather than haul out the pressure canner, but ok, I can see that.

But there’s an approved spaghetti sauce recipe, with very similar proportions, for pressure canning with no added acid.  Is there any reason why I can’t just use those times to pressure can a low acid tomato puree?

The response had two parts, the first stated that since that hadn’t been tested with pure tomato puree she couldn’t say that was safe (which I can understand, after all, if she agrees with me that it’s safe and I do something stupid with it and get sick, or die, from botulism, she doesn’t want to get sued).  But she should have just left it there.  The next part stated that most likely the tomato puree is going to be thicker than the spaghetti sauce so THATS why its not safe, cause the thicker the sauce the harder it is to get the heat to the center of the jar right.

Look, the tomato sauce (which is pure tomato puree if you follow the instructions) recipe calls for 28 pounds of tomatoes to make 9 pints of sauce.  That’s just about 3.11 pounds of tomatoes per pint of finished sauce.

The spaghetti sauce recipe calls for 30 pounds of tomatoes, plus other stuff, to make 9 pints of sauce.  That’s 3.33 pounds of tomatoes, plus other things, per pint of finished sauce.

I highly doubt that the tomato puree is going to end up thicker than the spaghetti sauce……

I haven’t decided if I’m going to try canning my sauce or not this year (though I’m highly tempted).  But I really dislike being given stupid reasons for why I shouldn’t do something…….

3 Comments

  1. Comment by Mrs. S:

    When I make marinara sauce, I squeeze out excess juice & seeds from the tomatoes, which makes the sauce thicker and probably also lower in acid. Sometimes low acid yellow tomatoes sneak into the mix too. The sauce also contains garlic, olive oil, and oregano, and probably less salt than most BWB recipes require. As such I figured a boiling water bath would be insufficient. I used the instruction manual from my pressure cooker to guess-timate an appropriate time & pressure. I used their guide for canning okra and tomatoes which is 10 lbs. pressure, pints for 25 minutes, quarts for 40 minutes. So far we are still alive. The only trouble I have had was with some of the newer canning jar lids. Stick with the ones made in USA, but even then you might find that they are using such thin metal that the lids can deform or fail to seal properly when used in a pressure cooker. Usually that problem appears right away. As with anything canned, if you don’t hear the pop when you open the jar, or it smells funny, throw away the contents.

    If you are really worried about the time, just process it as if you were pressure canning something really low in acid, like say pumpkin 10 lbs pressure, 60 min. for pints, 80 min. for quarts.

    • Comment by Ruth:

      Yup, another recipe that makes sense of it too.

    • Comment by Ruth:

      I’ve been pressure canning meats now for a couple years without issue. Husband loves having the pre-cooked chicken breast to use in soups, or pizza toppings, calzones, etc. And we both like having pre-cooked bacon to use in all sorts of things!