Oct 01 2013

Adventures in Canning: Revisiting Tomato Jam

Two summers ago, this tomato jam recipe transformed me from a canning dabbler into a canning convert. In January of 2011, while still living in Brooklyn, I rather abruptly decided that I was going to be a “canner”. This impulse stemmed from an innate drive to become more self-sufficient, to further my awareness of seasonality, and to invest myself in “creating”. Though I express my creative side through photography, I remain envious of crafters, knitters, and those who can quickly sketch a believable (or silly) image on a whim. My sketches are the same as they’ve been since I was 7: tulips, a rudimentary house, and a sun. So on a secondary level to seasonality and self-sufficiency, my decision to preserve allowed me to access a different side of creativity, and to share my creations with others.

As I taught myself the intricacies of canning – from pectin amounts, to jar preferences, to flavor combinations, to ensuring accurate seals – the reality of preserving food seemed more stressful than I’d envisioned when I was sitting on my couch in January, thumbing through expertly photographed books.

My hours spent canning in our galley kitchen that spring and summer were tinged with doubt; my arms were singed with boiling water and sputtering jelly lava. While each successfully sealed jar felt high-five worthy, I wasn’t awed by any of the flavors I developed, and I was continually frustrated by the water bath process. Every time I lowered jars into the canner, half would fall over. Or the handles on the canner would fall into the boiling water. And then when I’d retrieve the jars, warned by numerous sources to disturb them as little as possible, I’d inevitably tilt them or shake them while simultaneously scalding my forearms.

Mishaps aside, I never felt compelled to abandon home preserving that summer, but I did wonder if it would become as enjoyable as my books promised (and I know my husband wondered when he’d be able to walk into our kitchen when I was canning without being met by a wincing face and pleas to “leave the kitchen until I was done”.)

I credit this tomato jam for diverting me from a lifetime of scalding arms and mediocre creations. With this jam, I switched from water bath canning to oven based canning, via Rachel Saunders’ Blue Chair Jam cookbook. This is the method I write about with all of the canning recipes I post, and it started with this jam. Instead of dropping jars in water and steaming up the kitchen, I began to sterilize and seal them in the oven.

And, just as monumentally, this jam was the first jam I made that elicited reactions that made me want to create more concoctions just so I could hear that same excitement. That year both of our parents visited us for a final Thanksgiving in New York before we moved to Portland. The turkey was cooking slower than anticipated, so in an attempt to ward off crankiness, we pressed paninis with a recent batch of tomato jam. And though everyone knew they were about to eat a massive, nap-inducing dinner, no one could resist asking for another panini, professing unhindered and spontaneous compliments about the jam.

Canning is no longer the stress-inducer it used to be. This change partially comes from experience and maturity. But I also credit this jam for allowing me to find a calmer path. Though canning on a 90 degree day will never be relaxing, it’s no longer “get out of the kitchen!” stressful. I now have a 99.5% success rate with seals, and I’m starting to expand on tried-and-true recipes to draw the peak flavor out of various fruits.

I have no plans to let a summer pass without making tomato jam. Stirring the boiling pot feels like a fitting conclusion to a summer well-spent (and well-eaten). And I know from experience that slathering this sweet and savory jam on freshly baked bread will automatically improve a dreary February day.

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 overnight.  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.