Tuesday, August 7, 2012

Canning Tomatoes 101

As we become more discerning about what we eat and opt to buy fresh from the Farmers Market rather than the grocery store, it’s often said that “I wish I could get this in the winter.”  And while it’s nearly impossible to do unless you live in a temperate region, many items can be preserved for winter use and a big one for us is tomatoes, which we make into canned tomatoes, juice, and sauces.

Believing that many are intimidated by the prospect of canning, I thought I’d put together a little tutorial on preserving tomatoes using a pressure canner – it’s a lot quicker than a water bath canner.  My primary reference for preserving is “Keeping The Harvest” by Chioffi & Mead.

Jars – use only canning jars and not left over mayonnaise jars. 

Check them for any damage that could lead to breakage or nicks on the rim that would prevent sealing.  We just wash ours in the dish washer but they can be further sterilized by dipping in boiling water (more of a concern for low acid items like beans).

Tomatoes – We like to can with paste tomatoes (Kada, Quimbaya, Roma, San Marzano, etc.) as they have much less water in them, which must often must be cooked off later for sauces and they make a little thicker juice.  It takes a peach basket full (half bushel) to make a run (seven quarts).

More watery tomatoes work fine in soups but the more water you can, the more jars and shelf space it requires. 

For canned tomatoes, we cut out damaged areas (such as this spot caused by the fungus anthracnose, as seen on the one tomato below), blanch, ice water cool, and peel them. We then quarter them, squeeze out some of the water, and pack in jars, with 1 tsp. of canning salt - don't use table salt.

For juice, we core and remove bad places, then cook until soft enough to process – longer cooking will give them a different taste with less of a fresh tomato flavor.  We run them thru a chinois

and add the juice to jars (stirring the pan often to prevent water separation), with a tsp. of canning salt.  Use a canning funnel to keep the jar tops clean. .

For sauces, we do the same thing to the maters as for juice but have recently learned to simmer them all night before running them through the chinois.  We also tried a run of juice this way.  On our cooktop, we have to set the pan on a simmer plate to keep them from boiling. 

Bev used the food processor to chop some garlic (2 bulbs), onion (4 medium), celery (5 stalks), sweet pepper (3 med bells), and carrot (3 med) very fine and added it to the tomatoes (12 quart pot full) before cooking – adjust amounts to your taste.  This resulted in a basic tomato sauce that can now be used for Italian, Greek, and Mexican sauces depending upon the herbs and spices that are added at the time of use.

From right to left, here is a jar of tomatoes (cooked the least), regular juice, and cooked-all-night-juice (cooked the most) - note the more they're cooked, the darker the color.  We tried the cooked-all-night juice as an experiment, but it tasted more like sauce than juice so we’ll use it for soups and other cooking – now I know why Dad told me not to overcook the maters when he was training me, but you know us kids, we have to learn it the hard way.

To prepare the lids, boil some water in a sauce pan, turn off the heat and add the lids – rapidly boiling the lids can damage to seals.  I put my lids front-to-back-to-front so they don’t stick together. 

I stick my tongs in there as well to sterilize them.

After putting the product in the jars, run a wet paper towel around the rim to be sure it is clean and there are no nicks.  Then set the lids in place and tightly install the rings, whose sole purpose is to hold the lid against the jar rim until it seals.

Canner – We use a 16 quart Presto Pressure Canner (dial type) which will process seven quarts of product and there is nothing to fear from these devices unless you try to use in from another room, which is a bad idea once it starts building pressure.  Always read the instructions with your canner.

To can the tomatoes, add two quarts of water (depends on canner size) to the canner containing the lifting basket, which also keeps the jars from sitting on the canner bottom (important). 

Then sit the jars into the canner with a little gap between them if possible, and add the lid, after checking the seal to be sure it’s properly in the slot for it (over time, the seals have a tendency to get smaller and won’t seal properly – our local hardware store has replacements for about six bucks). 

Once the lid is on, turn on the stove heat as hot as possible and after about 10 minutes, steam should begin to come lightly from the vent, set a timer for 10 minutes (you can read the paper during this period as well as the previous 10 minutes).  After 10 minutes steam should be shooting from the vent in a steady stream and the jiggler is now put on the vent – you now are confined to keeping an eye on the canner.

When the pressure gets to 11 lbs., start a 10 minute timer (for tomatoes) and throttle back the heat to medium and watch the gauge, making minor corrections to maintain around 11 lbs.  (After 5 minutes it will usually stay close to the 11 lb. mark).  A gas range works best as the heat adjustments are immediate. If using an electric range, the canner may need to be moved to a different eye on medium heat to prevent the canner temperature from overshooting the 11# mark too much – 1 pound for a short time is okay.

When the timer goes off, turn off the heat and go read the paper – DO NOT OPEN THE CANNER UNTIL THE PRESSURE IS ZERO or bad things will happen - also don't run cold water on it to speed the process, like you might do with a pressure cooker. 

When the pressure gage reads zero, remove the canner lid (back side first so the heat goes that way), remove the jars with a jar lifter

and sit them at least 1” apart to cool and you’ll hear them sealing over the next several minutes.  Once the lids seal and the jars are cool, I like to remove the rings and test the seals by giving them a little pull with my finger – you will not be able to open a properly sealed jar with your finger – unless you are mighty man. 

Since we have too many rings and they are a pain to store, I run them through the dish washer, wipe the jar threads and lightly reinstall the ring – like I said this is just for storage. 

Some folks just leave them on after canning but this is unnecessary for properly sealed jars and requires lots of rings.  You really only need enough rings for a canner load or two, and we trash them when they get some rust as they are more difficult to get on and off.

Starting with clean jars and pre-washed tomatoes, it takes 2- hours total time to do a run of tomatoes - juice takes about 3½ as the tomatoes require about two hours to cook. 

All photos can be enlarged by clicking on them and I can't figure out why I have two different type sizes.
Have a great day and thanks for stopping by Almost Heaven South.

One year ago:  None


July, 2012 event date


  1. I hope I'm not the only one that had no idea how much effort and work went into canning tomatoes. And that doesn't count the fact that you took the time and trouble to grow your own!

  2. My friend Cauleen lives just a couple block away and for a few years, I would borrow her water bath canner rather than run and buy one. Last year I decided to buy my own. Stood there for probably 10 minutes trying to decide on a water bath or pressure. I chose water bath. I still think pressure canners sound so complicated. Maybe I should just watch someone do it and I'd feel more comfortable about the process.Anyway, I love canning and all those pretty jars lined up with Summer's bounty. Tis the season. Great tutorial Larry.

  3. great tutorial - nothing better than home grown, put up foods...
    canning is not difficult, it just takes time, like a well made cake, something we have to allow ourselves do

  4. I keep threatening to get canning equipment but it never happens. I think I'm a bit intimidated by it actually..... which is silly because look at what you can produce!!!

  5. I remember my grandmother's old pressure cooker and how nervous it made me. I was sure it was going to explode at any minute. What a treat to be able to have home canned tomatoes during the winter months.

  6. Larry, Laurie and I love your and Bev's energy...as well as your finished products! We are just so lazy in comparison... Take Care, Big Daddy Dave

  7. I used to help my MIL in can tomatoes, then we moved to rural NJ and I did my own canning because I had such a huge vegetable garden. I do miss those years.

  8. Wow Larry this is great. Looks like my Mom's kitchen many, many years ago. Lids and jars and tomatoes everywhere. Very, very nice. Thanks!

  9. Look at you getting all fancy with your pictures! Looks like you're putting those gifts and lessons from your friends to good use. Great job, Dad!

  10. Awesome tutorial, Larry! I'm still bummed that I didn't get a single full size tomato from our garden this year. Not sure if it was the heat or our traveling or what, but I am telling myself there will always be the next garden. Fall will be here before I know it, right?

  11. My mom always canned the best tomatoes that she would put in chili. I have only canned them once or possibly twice but I used a water bath canner. I don't have the pressure cooker style. You've made me want to can some but I think our tomatoes aren't producing that well because of the strange weather and temperatures.

  12. There's nothing better than opening up a jar of summer love in the dead of winter!

    I've been a canning queen this past week! Enjoy your hard work!


  13. I thought this was a great tutorial Larry. I have a water bath canner but just don't have the room to store it or the jars at our summer cottage. I make a basis tomato sauce out of the tomatoes from the garden and freeze it.

  14. So much work! But so greatly appreciated when winter sets in and you want fresh garden taste. I canned tomatoes once, once. It really is a job for 2 or more and I was alone. Now I only have time for Mason Jar Meals, maybe someday I will can again, but these kids are keeping me busy right now;-)

  15. Thank you so much for such a self-explanatory and very understandable post on canning tomatoes (with pictures to boot!). Last year, my husband Bill used his method of non-water bath, and I ended up throwing away 20 quarts, that's right, QUARTS, of canned tomatoes. Needless to say, I was one pissed off gardener!

    I'll never let him can tomatoes any other way but this way from now on.!

    Thanks so much!


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