canning tomatoes

New Tool Makes Canning Easier

I taught a class on food preservation this summer at Sterling College and one of the things that had my students stumped was the idea of putting on the screwbands on the canning jars just "finger-tight."

Applying the SureTight Band Tool 

Applying the SureTight Band Tool 

"Finger-tight"—the term is courtesy the National Center for Food Preservation (the ultimate authority on food preservation)—is something of a misnomer.  I suppose they chose the term to distinguish it from Ninja-tight or "plumbing-tight" but it implies a certain delicacy when a certain firmness is needed.

If a screwband is applied too tightly on a canning jar, there is the potential that the jar will explode in the canner.  But if the screwband is applied too loosely, the contents of the jars can bubble out, deposit food debris on the rims, and prevent a good seal.

Apparently, other people find the term "finger-tight" confusing because Ball Canning has come up with a tool to take the guess work out of it.  The tool is called the "Sure Tight Band Tool" and it can be found for between $7 and $15 dollars wherever canning supplies are sold and online.  What surprised me about the tool—and I've been canning for years—is how tight "finger tight" is.  I think "firm-tight" would be more accurate...

To tighten screwband, turn handle until arrows align.

To tighten screwband, turn handle until arrows align.

In any case, this is the time of year I when I can tomatoes, when the kitchen is cooled off (and before my freezer fills with a half pig share).  My tomatoes were dumped into jumbo plastic bags and unceremoniously frozen last summer.  I dump the tomatoes still frozen into a stockpot and cook them down into puree or paste. 

Just dump the frozen tomatoes into a stock pot and begin cooking.

Just dump the frozen tomatoes into a stock pot and begin cooking.

After the tomatoes have cooked down, strain out the seeds and skin.

After the tomatoes have cooked down, strain out the seeds and skin.

For my most recent batch, I made paste, cooking down the strained puree in an uncovered stockpot for about 16 hours, until a spoon leaves a trail when the paste is stirred.  Per USDA instructions, I added 1 teaspoon of citric acid.  

Cook down the puree until a spoon will leave a trail.  A slow cooker ensures the paste doesn't burn -- and it is easier to clean than it looks.

Cook down the puree until a spoon will leave a trail.  A slow cooker ensures the paste doesn't burn -- and it is easier to clean than it looks.

The formula is 14 pounds of tomatoes, cooked down to 8 or 9 half pint jars, with 1 teaspoon of citric acid.  I poured the paste into canning jars, leaving 1/2-inch head space and sealed the jars with my new band-tightening tool.  Then I processed the paste for 45 minutes. 

And every jar sealed.



Preserving Tomatoes and One-Dish Dinners

When preserving tomatoes, you get more bang for your buck with plum tomatoes (meaning more can be put in a jar, but I can a mix of tomatoes, whatever I need to preserve.

When preserving tomatoes, you get more bang for your buck with plum tomatoes (meaning more can be put in a jar, but I can a mix of tomatoes, whatever I need to preserve.

For gardeners who love tomatoes, tomato season is both a joy and a burden.  It's a joy because nothing beats a fresh tomato as a snack, as an add-on to a sandwich, as a quick sauce for pasta, as a side dish, sliced and topped with a drizzle of oil and vinegar and a sprinkling of salt.  As we walk through the garden, we pop cherry tomatoes in our mouths, almost without thinking.

The thinking part does come.  What to do with all those tomatoes?  Whether all those tomatoes will be enjoyed fresh or whether they will be canned, I have a recipe for you.

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101 One-Dish Dinners is filled with recipes that bring dinner to the table quickly, with a minimum of fuss.  There are a lot of my family favorites contained in those pages, a lot recipes that are streamlined for speed and ease.  These are the recipes that my husband makes when I am out of town and my adult kids make for themselves and their friends. 

The one ingredient that makes a lot of these recipes sing is the tomato—fresh in one-dish salads, canned in soups and stews you might want to make when the weather cools.  In fact, I counted 22 out of 101 recipes that use tomatoes in one form or another. 

So, let's say you might want to make one of these recipes every two weeks or so.  That means you'll want to put up 26 quarts of tomatoes.  But, of course, just about everyone is going to want to make some form of spaghetti—with meat sauce, with sausage, or with a simple tomato sauce—every two weeks, so that's another 26 quarts of sauce or puree you'll need.  Homemade pizza is so much better than the greasy store-bought or delivery pizza, so add another 14 quarts of sauce or puree.  That's 64 quarts of tomato products.  And I haven't even thought about ketchup or salsa yet.

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While I am in a calculating mood, let me add that a lot of recipes in 101 One-Dish Dinners and elsewhere call for a 28-ounce can of diced tomatoes.  That's equivalent to a quart of home-canned tomatoes (mine weigh in at anywhere between 25 and 40 ounces, depending on the variety and how much I managed to squish in).  Another way to look at equivalents is that a 28-ounce can holds 3 cups.  So you can drain your home-canned tomatoes (save the juice), measure, and return enough liquid to make 3 cups.  Or just figure that your quart of home-canned tomatoes is equivalent to a 28-ounce can and don't sweat the difference.

Tuscan Tuna Salad with White Beans -- served with a sourdough biscuit from  The Backyard Homestead Book of Kitchen-Know-How.

Tuscan Tuna Salad with White Beans -- served with a sourdough biscuit from The Backyard Homestead Book of Kitchen-Know-How.

Now I have to go—I have more tomatoes to can.  And when I'm done, I'll whip up a dinner with a recipe from One-Dish Suppers.  Last night I made a Mediterranean Tuna Salad with White Beans and the night before it was Antipasto Antipasta Salad.  Quick one-dish meals make life so much easier when you are busy.



Steam Canners are Safe to Use!

I have a guilty secret.  For years, I’ve been canning my high-acid foods (pickles, fruit, jams, and tomatoes) in a steam canner—even though the USDA has frowned upon the practice and even though I have taught classes using the boiling water bath canner.  It was a “do as I say, not as I do” practice. 

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I use the steam canner to process tomator puree.

Finally, too late to include in my new book, The Backyard Homestead Book of Kitchen Know-How, researchers from the University of Wisconsin, Madison, funded by a grant from the USDA and the National Center for Home Food Preservation (NCHFP), have concluded that steam canners (properly called “atmospheric steam canners” to distinguish them from pressure canners which use pressurized steam) can be as safe and effective as water bath canners when properly used to preserve acidified or naturally acidic foods.

Why do I prefer the steam canner to the boiling water bath canner? Because they speed up food processing.

The boiling water bath canner is a large pot with a lid and a rack to hold jars—large canners hold up to 9 quart jars and the small ones hold up to 7 quart jars.  When you heat the water in a boiling water bath canner, you have to bring at least 5 quarts of water up to a simmering temperature.  Then add your jars and wait for the water to come to a boiling temperature, adding even more water if needed to cover the jars with at least 1 inch of water.  This can take 30 to 60 heat-filled minutes, before you even begin processing, depending on the size of your canner, whether the jars were hot-packed or raw-packed, and the BTU output of your stove.

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Heating water is faster in a steam canner than in a boiling water bath.

By contrast, the steam canner is a 2-quart pot with a perforated metal rack for holding jars and a tall dome lid that allows a steady stream of steam to flow around the jars. There is less water to heat and less time spent waiting for the water to heat.  Best of all, pickles are exposed to less heat during steam canning, resulting in crisper pickles.

The University of Wisconsin released guidelines for using steam canners and I am replicated them here.  My remarks are in square brackets.

1. Only steam can foods high in acid, with a pH of 4.6 or below. [[This means pickles, fruit, jams and jellies, and acidified tomatoes—i.e., tomatoes to which you have added 1/2 teaspoon citric acid per quart.]]

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Adding citric acid to tomatoes acidifies them for safe canning.

2. Always use a research-tested recipe developed for a water bath canner. Acquire recipes from university extension programs or from the NCHFP ( The booklets that accompany steam canners usually don’t provide safe instructions.

3. Heat jars prior to filling them with food and minimize the amount of cooling time that passes prior to processing. You can use half-pint, pint, or quart jars.  [[I set the jars upside down on the canner rack and let them heat as I heat the water in the pot below.  When the water has boiled for about 10 minutes, if I am not ready to can, I turn off the burner, but leave the jars as they are.  They will hold their heat.]]

4. Process jars only after the temperature reaches pure steam at 212 degrees Fahrenheit. Wait to start the processing time until the canner has vented and a full, steady column of steam appears. Monitor the temperature with a thermometer.  [[The dome lid has holes to release the steam.  This is why you can’t adapt another pot to be a steam canner—you need to see that steam escape.]]

5. Modify processing time for elevation — in general, add 5 minutes for each 1,000 feet you’re above sea level in elevation.

6. Only use recipes that require 45 minutes of processing time or less, as the amount of water in the canner may not last any longer. Don’t open the canner to refill the water while processing foods. [[Not a problem at most elevations.  Most pickles and jams require 5 to 10 minutes of processing time.  Acidified tomatoes and tomato purees require 40 minutes.]]

7. Cool the jars in still, ambient air. Cool jars on a rack or towel away from drafts. Don’t place them in the refrigerator to hasten the process.

Prices for steam canners vary widely.  Go for the simplest, least expensive one you can find.  My steam canner is about 35 years old and has been beaten up in suitcases when I take it to demos.  It will last a lifetime.  And remember: It is only good for high-acid foods, like the applesauce I am about to make.

It's applesauce time!

It’s applesauce time!

Playing Ketchup

Playing Ketchup

 We grew about six different varieties of cherry tomatoes, including some black, some currant, some grape, some yellow.

I’m always playing catch-up with my garden and my life.  So one of my best tricks for keeping up with my tomato harvest is to freeze the tomatoes as they ripen and make sauces and salsas when I am ready.  Why mention it now?


Because I just turned a 10 pound bag of cherry tomatoes into sauce.  So I figure while you are contemplating how many tomato seeds to order, I will tell you how to tame sugary sweet, amazingly prolific cherry tomatoes into sauce.

 The finished sauce.

There are, of course, plenty of things to do with cherry tomatoes as they ripen.  And because they tend to ripen earlier than beefsteaks or Romas, I do find myself giving over a large portion of my tomato “orchard” to cherries.  Cherry tomatoes are dependable, even when the weather is not.


At some point, a daily harvest of cherry tomatoes yields more than one household could ever eat fresh. Not a problem. I buy jumbo-size plastic bags and the cherry tomatoes go directly into the bag, unwashed, unstemmed, and the bag goes into the freezer.  If the bag isn’t completely filled, I can add more as the tomatoes ripen.


At some point (like now), I’m ready to can them.  The tomatoes go from bag to colander for a rinse, and then from colander to pot to cook them enough to break them down.  Then I run the tomatoes through a food mill, which takes care of the skins and stems and most of the seeds.  The resulting puree is much less than expected, since cherries are mostly seed and skin, but at least they were harvested and put to use, rather than popping up as volunteers next season (though there will be plenty of those).

 First I cook the tomatoes to break them down.Then I run the sauce through a food mill.

I cook the puree down to a consistency good for sauce.  If I’m in the mood to pressure can, and no reason not to, I’ll add lots of sautéed onions, garlic, bell peppers, and herbs-- either frozen pesto or dried or frozen basil leaves, plus dried oregano, thyme, and rosemary.  Salt and pepper, of course.  If the sauce is still too sweet, some balsamic vinegar tones down the sweetness nicely, as does a little soy sauce.  Of course, with no added vegetables, it would be fine to can the tomatoes in a boiling water bath.  But the reason to master using a pressure canner is to be able to have foods that are ready to be heated and served.

 The sauce is cooked down until it has a nice consistency.

The sauce is still sweet but it pairs particularly well with sausage, I think.  Its just fine on pasta, on pizza, on toasted bread with cheese. Maybe it is a little sweet for all applications, but it is just fine for an occasional meal.

 Dinner is served!

The cherry tomatoes could have gone into ketchup, with the natural sugars in the cherry tomatoes replacing some of the added sweetener in the recipe. 


With frozen cherry tomatoes and long, cold winter nights, there’s no reason not to get some canning done when the extra heat in the kitchen is more than welcome.