Q and A: acidity of tomatoes, soft chicken eggshells, and vitamin C to keep fruit fresh — 5 Comments

  1. Sometimes it isn’t that the tomato is less acid, it’s that it is more sweet and the sweetness hides the acid taste, if that makes sense. I’ve wondered how much soil, amendments, and field ripeness affect acidity but don’t have any data (I freeze my tomatoes whole). Here’s a chart for acidity of some tomato varieties
    scroll down to the last post. On the way to that chart is variety information from the U of Minnesota. On the chart I was surprised to see Amish Paste, Polish Giant Paste and Jersey Devil listed as above 4.6 (the safe pH for canning with no added acid) because these are all very old OP varieties that have been home and commercially canned for generations, but Rutgers (also an old bred for canning tomato) is 4.5. Pineapple is listed as 4.62, but I recently had a Pineapple tomato that tasted so sweet I didn’t enjoy it. Neither Johnny’s nor Tomato Growers Exchange lists acidity related to canning in their descriptions. Although canning instructions changed in 1994 supposedly because of “low acid” tomato varieties, I wonder if there’s something else involved that needs more research. Colorado State University Extension Service published this information: “Research has found several conditions that can reduce the acidity of tomatoes. These include decay or damage caused by bruises, cracks, blossom end rot or insects, and overripening. Tomatoes grown in the shade, ripened in shorter hours of daylight, or ripened off the vine tend to be lower in acidity than those ripened in direct sunlight on the vine. Also, tomatoes attached to dead vines at harvest are considerably less acidic than tomatoes harvested from healthy vines. Decayed and damaged tomatoes and those harvested from frost-killed or dead vines should not be home canned.” But as Jackie said, to be safe, add lemon juice or vinegar.

  2. Zak and Karla,

    Yes, they are, but they are tasty tomatoes. If you can them, you must add lemon juice or vinegar. There are dozens and dozens of high acid tomatoes. Just research them when you buy seeds and you’ll learn a whole lot.

  3. Hi, Jackie,
    I’m wondering the same thing as Zak. I think you’re saying those varieties are low-acid, right?
    Do you have a list of high-acid varieties, or can you recommend a resource for finding out? Or is it just something to research as you buy seeds?
    Thanks for all your great advice and wisdom that you share with us!

  4. In regard to the fragile egg shells, my grandmother always said to keep crushed oyster shell in a container in the hen house so they can partake of it free choice….I have always followed that advice and the only time I had problems with soft thin shells was when I had let them do without it for an extended time. I purchased layer mash from our local farm store and they told me it wasn’t necessary to use the crushed oyster shell as their feed had sufficient calcium to ensure good shells. However, when I followed their advice my hens had the shell problem. In my area the crushed shells ware pretty cheap and a 50 lb. bag lasted a long time for 2 or 3 dozen hens. I just poured it into a wooden box in the corner near the feeder. and when it got down about halfway I’d get a backup. One bout of poor egg shells was sufficient. Also in winter if it was too cold or snowy for the hens to go into the yard I gave then a square of hay a couple times a week. They love it….Rick