Hello,

I'm an experienced canner but today I'm actually researching the different methods for canning tomatoes and I'm realizing I'm confused about something.

Here's the NCHFP instructions for canning crushed tomatoes, and here's the instructions for quartered or halved tomatoes. Both of them tell you to peel and quarter (or halve) your toms, then cook them gently until hot through. I'm water bath canning at below 1,000 feet so those are the stats I'm focusing on:

In the crushed toms recipe, it says to crush a few of them at first, to create some juice, then add the rest of your quartered toms and cook gently 5 mins. It says there is no need to crush the rest, that they will soften during cooking. Then ladle hot toms/juice into jars, and process 45 minutes.

In the halved or quartered instructions it says to put them all in a pot and cover with tomato juice, then cook gently 5 mins, ladle into jars, and process 85 minutes.

To me, these seem like EXACTLY the same process with the exact same end product. In both cases, aren't the quartered tomatoes you're gently boiling on the stove getting equally soft and juicy before being ladled into jars? So then why do you process the one 45 minutes and the other 85 minutes? What is so different about the quartered tomatoes cooked in the juice from the few crushed toms in option 1, and the quartered tomatoes cooked in presumably separately-purchased tomato juice on the other? Aren't they both just quartered toms cooked in tomato juice? Reading these two sets of instructions, I feel like the product you are ultimately ladling into your jars is identical, so why the radical difference in processing time??

Would love to understand how this conclusion is arrived at. I'm not doubting this is all correct and scientifically safe! I'm just trying to understand why.

by Johann_Sebastian_Dog

4 Comments

  1. My guess is that the 85 minute process time is to insure full heat penetration of the halved/quartered tomatoes when doing a RAW pack.

  2. DancingMaenad

    The 2nd recipe is for *Whole* tomatoes as well. The longer cook time is to ensure heat penetrates the whole tomato.

    Edit- the 2nd recipe is for whole and halved, not quartered at all, so no its the not same as using quarters in the crushed recipe. The tomatoes would be 2-4x larger so require longer processing time.

  3. fire_dawn

    My understanding is that in the crushed recipe there’s some dependence on pectin and other enzymes being released in the initial crushing that kick started the breakdown process that continues as you add more.

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