Aug 23 2011

Adventures in Canning: Tomatoes

Canning and preserving tomatoes felt unsettlingly like participating in a high school biology class experiment.  I dissected each plum tomato, peeling its skin away from its body.  I then squished these tomatoes into jars, squeezing out excess juice, leaving these naked fruits to suspend in mid-air, as if preserved in formaldehyde.

The process of making tomato jam could be viewed as even more gruesome, at least to an observer.   By the time I neared the end of dicing up 4.5 pounds of tomatoes, I was hacking at them.  Big dice, small dice?  Whatever.  I was hacking so violently that I felt like the demon barber of Fleet Street (a play that makes me queasy from its very gruesomeness!).

Moving away from the red splattered countertops in my kitchen, I’m filled with relief when I think about this upcoming winter.

We have two cans of whole plum tomatoes--which will equal at least two dinners featuring tomatoes at their peak of flavor.  We also have 5 jars of tomato jam: jam that can be slathered on sandwiches, paired with cheese, and baked in galettes.

Canned Whole Tomatoes

Adapted from Put ‘Em Up!

Makes a quart of tomatoes (double the recipe for another quart and so forth)


3 lbs plum tomatoes (I used Marzano)

2 tablespoons of lemon juice

1 teaspoon of salt


  1. The very first thing you need to do is also the longest step.  Fill your canner with water, turn the heat on, and wait.  It will take a long time--45 minutes to an hour--for the canner to heat up and approach boiling point.  Put your jars in the canner while the water is heating, to heat them up.
  2. When the water looks like it’s approaching boiling point:  start your tomatoes!  First, fill a bucket/large bowl/your sink with ice water.  Heat up a smaller pot of water to boil and drop your tomatoes in 5-6 at a time for 1 minute.  Immediately transfer the tomatoes to your ice water container.  Repeat with the remaining tomatoes.
  3. Remove the tomatoes from the ice bath.  Core the tomatoes and then peel away the skins with a small paring knife.
  4. Remove your jars from the canner (carefully!) but maintain the heat on the canner.  You want to ensure that the water is boiling when you put the filled cans back in.
  5. Put lemon juice and salt into the jars (I recommend a quart jar, but liter jars work well, too).  Pack the tomatoes into the jars one at time, pressing firmly to release some of the juices.  Don’t crush the fruit!  Continue packing the fruit until you reach an inch from the top.  Tomatoes should be covered by 1/2 an inch of their liquid and leave 1/2 inch of headspace between top of the liquid and the lid.  I had to top my second jar with boiling water to achieve the proper headspace.
  6. Can:  Appropriately affix the lids and then process for 85 minutes (yes, you read that correctly!).  Turn off the heat and let the jars rest for 5 minutes.  Remove the jars and set aside for 24 hours.  Check the seals and store in a cool place for up to 1 year.

Tomato Jam

Adapted from The Blue Chair Jam Cookbook

Makes approximately 5 8 ounce jars


4.5 lbs medium tomatoes

1.5 lbs white cane sugar

1 1/8 ounces freshly squeezed lemon juice

1 pinch of salt


  1. Place a saucer with 3-4 teaspoons in your freezer.  You’ll use this to test the jam later.
  2. Bring a medium pot of water to boil. Prepare an ice bath.   Put the tomatoes into the boiling water for 1 minute to loosen their skins.  Transfer the tomatoes to the ice bath.
  3. When they’ve cooled down, peel the skins off.  Then, chop the tomatoes into medium pieces.  Transfer these tomatoes (and the subsequent juices) back into the mixing bowl.
  4. Add the sugar and lemon juice, stirring well to combine.  Transfer the entire mixture to a large non reactive stock pot.
  5. Bring the mixture to a boil over high heat.  Add the salt and decrease the heat slightly.  Cook, monitoring the heat closely, until the jam starts to thicken.  This process will take 45 minutes or longer.  Scrape the bottom of the pan with a rubber spatula to ensure that none of the jam starts to stick.  For the final 15 minutes of cooking, stir constantly.
  6. After 40 minutes, when the jam starts to thicken, test it for doneness.  Put a small dollop on one of the freezer spoons and return for 3-4 minutes.  If the jam is gloppy and runs slowly when you nudge it and turn the spoon upside down, your jam is nearly done.  If it runs or is too watery, continue to cook and then test on another freezer spoon.

Are you storing it?

Using a stainless steel spoon or a ladle to transfer the jam into its storage containers. Let cool on the counter before putting into the refrigerator.  Keep in the refrigerator for up to 3 weeks.

Are you canning it?

Ladle into oven sterilized jars, leaving 1/4 inch of headspace.  (To sterilize your jars in the oven, heat your oven to 250 degrees before placing your jars and lids onto cookie sheets.  Keep in the oven for at least 30 minutes, but longer is fine, too.)

After filling your jars and securing the lids (use gloves if the jars are too hot to handle) carefully put the jars back on the cookie sheet(s) for 15 minutes.

Remove the jars from the oven keeping them on their sheet(s).  Put the sheet on a wire rack and cool them over night.  Test the seal and place any that didn’t seal into the refrigerator.  Store the rest in a cool place for up to 1 year.