Part 2: Home-canning Heirloom Tomatoes – A step-by-step guide with safety tips!

craig canned maters June 7 2016

By Ciranna Bird, CFSA Member and Medical Writer for Farmers

Seek the experts

Home-canning expertise used to be handed down through generations. For example, my dad and uncles learned how to hunt deer with compound bows, shoot wild ducks and fish for rainbow trout in the Colorado River from my grandpa. My grandmother taught my Aunt Pat how to home-can trout, as well as the vegetables and fruit they grew in their yard. Unfortunately, I lost contact with my dad and his side of the family for fourteen years, after my parents’ divorced. Since I didn’t grow up with this culture of food self-sufficiency or even have the desire to learn how to be a home-canner at that time, I like many adults my age am looking for ways to learn these skills. Where can we start?

Chatham Co Cooperative Extension Canning Class

Chatham Co Cooperative Extension Safely Preserving at Home class

Based on my excellent experience attending a class at the Chatham County North Carolina Cooperative Extension service, I would recommend your local Cooperative Extension Service county center. Visit if you live in North Carolina and if you live in South Carolina to search for the office nearest your home. The Cooperative Extension Service offers free testing of your pressure canner gauges as well as affordable and informative courses.

Check out Part 1 of this series to gain 5 more motives to embrace home-canning.

Research the process

In the “Safely Preserving at Home” course, family and consumer sciences extension agent, Phyllis Smith, shared the most up-to-date, research based information on how to safely home-can vegetables and fruits. The participants of the workshop were a mix of newbies like myself and experienced home-canners. We walked away with copies of the 37th edition of Ball’s Blue Book Guide to preserving, handouts describing the parts of a typical pressure canner, frequently asked questions, and electronic resources that have the most current instructions and tested canning recipes. The interactions and questions during the class revealed that there was new information to learn even for those with prior years of hands-on experience.


New scientific research, newer models of canners, and a better understanding of the ways to reduce foodborne illness, all have resulted in improved and safer recipes and methods over the years. To benefit from all the progress made, it is important to seek out the most up to date guidance from a trusted source. I emphasize the word trusted because I recently found a canning book for home-canners that was published in 2011, which prided itself on skipping vital safety steps.

For my piece of mind, I encourage the readers of this article to use the United States Department of Agriculture (USDA) Complete Guide to Home Canning. Scientists and researchers at the USDA and Cooperative Extension Service universities, including Clemson University and North Carolina State University, have spent years developing the perfect the process of preserving tomatoes in glass jars.

They have identified the bacteria, yeasts, and mold that cause spoilage in tomatoes and identified the exact temperature and amount of time needed for processing and cooling to destroy them. In their research laboratories, scientists use the same size canners and same size glass jars that are available to the public.

These men and women from the USDA and Cooperative Extension services have tested thousands of variables (are the tomatoes packed into the jar raw or hot? Are there pieces of tomato in the jar or is it just the tomato juice? Are the tomatoes canned in a pint-sized jar or a quart-sized jar? Are you using a boiling-water canner or a pressure canner? Etc.) to identify the ideal conditions for home-canning our food safely..


CFSA is growing a regional food system that is good for consumers, good for farmers and farmworkers, and good for the land. Join CFSA’s Perennial Givers Guild and your monthly donation of any amount will help us grow local & organic from seed to plate.


Follow the recipe

Home-canning recipes must be followed exactly as written. Canning food is different than preparing a meal that you will eat within a few days. When you add the wrong ingredients or try out a new recipe for a meal you risk the chance that the food might not taste as good as you hoped it would.

In the home-canning world, if you substitute ingredients, attempt to double or halve the recipe, fail to reach the target temperature for the exact time the stakes are higher. The jars may not seal properly which could lead to food spoilage and waste. Worse, if the bacterial spores that produce botulinum toxin aren’t destroyed, eating the canned food which may look and smell perfectly normal may lead to paralysis and death.

At this point you might be saying “Wait a minute! My Aunt Pat (you can fill in the blank here) has been canning almost her whole life. She hasn’t ever used a recipe and she’s perfectly fine. Nobody has gotten sick from eating the canned food she prepares.” I don’t have a good response to this reasoning. I’m grateful that my Aunt Pat who still home-cans is alive and well in Colorado. I also feel passionate about sharing information with the readers of this article about the value of following up to date, trustworthy recipes exactly as they are written.

A recipe for making crushed tomatoes with no added liquid

To keep this recipe simple and provide the exact processing time, I have chosen the following options: The processing time listed below is specific for the use of a boiling-water canner. The processing pressure and time are different if you are using a pressure-canner. The processing time below is specific for the use of pint-sized jars with a boiling-water canner. The processing time for boiling-water canners is longer if you use quart-sized jars. A pint is equal to 2 cups; a quart is equal to 4 cups of food. The processing time below is specific for the use of pint-sized jars with a boiling-water canner in places where the elevation level is less than 1,000 feet above sea level. The processing time for boiling-water canners is longer if you live in mountainous regions. To find out the elevation level of your county view the North Carolina Topographic Map at or the South Carolina Topographic Map at

USDA Guide 3 Tomatoes and Tomato Products page 7

USDA Guide 3 Tomatoes and Tomato Products page 7


1.      Harvest or buy 14 pounds of organic tomatoes from your local farmer:

Size: medium to large
Color: Any color (yellow, purple, pink, green, orange, striped, red, etc.)
Shape: Any shape (Round, funny-looking, pumpkin shaped, pointy, etc.)
Condition: Firm tomatoes picked from living tomato vines. It is tempting to think that it is okay to use soft over-ripe tomatoes since they are going to be softened by the canning process anyway. However over-ripe tomatoes are soft because of the enzymes, bacteria, yeast, and mold that are breaking them down. Choose plump, firm and good-smelling tomatoes to ensure the best taste and safest product.

2.      Gather your instructions, equipment and ingredients

Visit your local Extension Service to get a hard copy or download the most recent version of the following USDA Home-Canning guidance material at Download Guide 1 – Principles of Home Canning and Guide 3 – Selecting, Preparing and Canning Tomatoes and Tomato Products

  • Lemon juice (9 tablespoons) or citric acid (2 and ¼ teaspoons)
  • A boiling water canner (16 quarts or larger)
  • Nine mason jars – pint-sized, heat-tempered glass
  • A canning rack to hold the glass jars
  • Two-piece vacuum caps that fit the mason jars (1) unused metal lids with the sealing compound on the outer edge and (2) metal screw bands
  • Thermometer
  • Large cooking pots
  • Cutting board and knife
  • Wooden mallet or spoon
  • Clean dish clothes and paper towels
  • Jar lifter
  • Canning funnel
  • Plastic spatula or bubble remover
  • Headspace tool or measuring tape
  • A magnetic wand to remove and attach lids
Canner funnel with elevated rack

Canner funnel with elevated rack

3.      Prepare the jars, lids, and canner

Follow the instructions in Guide 1, pages 14 and 15.

4.      Prepare the crushed tomatoes

Follow the instructions in Guide 3, page 7.

5.      Fill one hot jar at a time:

a)      Add 1 tablespoon of lemon juice or ¼ teaspoon of citric acid to the bottom of the hot pint-sized jar according to Guide 3 page 5.

b)      Fill the hot jar with the hot tomatoes and leave exactly ½ inch of unfilled space in the jar between the food or liquid and the rim of the jar (Guide 3 page 7). This space is called the headspace and allows the food to expand and form a vacuum seal.

c)      Remove air bubbles, food debris from the rim of jar, and add the lids. To see pictures and more detailed descriptions of how to do these steps refer to Guide 1 page 15-16.

d)      Place the filled, sealed jar onto the canning rack that is elevated above the simmering 180 Fahrenheit degree water in the boiling-water canner.

e)      Repeat steps a – d until all the jars have been filled.

6.      Process the pint-sized jars with a boiling-water canner at an elevation of 1,000 feet or below sea level:

a)       Lower the canning rack into the boiling-water canner which is already filled halfway with simmering water.

b)      Follow the steps on Guide 1 page 18 to ensure a continuous time of 35 minutes of a rolling boil.

c)      Follow the steps on Guide 1 page 18 to remove jars from the boiling-water canner.

7.      Cool the jars for 12-24 hours.

Follow the instructions in Guide 1 page 25.

8.      Check the jar seals.

Follow the instructions in Guide 1 pages 25-26.

Enjoy your delicious, local, organic canned tomatoes

Pop open a jar of your tomatoes, add your own seasonings, and use them to make lasagna, pizza sauces, stir-fry, stews and anything else you can think of. I’ll leave you with this quote from the NC Tomato Man, Craig LeHoullier: “I think that it is fair to say that we use our canned tomatoes in any cooked recipe – risotto, soups, stews – anything the commercial canned tomatoes goes into is improved if using our own home canned tomatoes.”

Beef Tajine with home-canned heirloom tomatoes

Beef Tajine with home-canned heirloom tomatoes

Ciranna Bird helps local farmers educate their customers on the health benefits related to small-scale pasture-based production of meat, dairy, and eggs. On July 21st, she will be presenting a workshop entitled “Protect your egg-laying hens and customers from Salmonella” at the Inter-Faith Food Shuttle. Registration is first come first serve. Information on her other speaking engagements, as well as her NC food blog, can be found at

Part 1: Home-canning Heirloom Tomatoes – Leaving the canned goods grocery aisle behind

TomatoesBy Ciranna Bird, CSFA Member and Medical Writer for Farmers

Tomato season is my favorite time of year. From July through September, my vision, taste buds, and tactile senses are delighted with tomatoes of all sizes, shapes, and colors. Visit any farmers market and you will find organic, juicy, flavorful tomatoes which have been grown from seeds that have been preserved over the years by local farmers. These heirloom tomatoes have enticing names such as the Cherokee Purple, Anna Banana Russian, Tasmanian Chocolate, and Brandywine.

My favorite way to eat organic heirloom tomatoes is raw and unseasoned. After washing them I pop the grape-sized tomatoes in my mouth like popcorn, or sprinkle them in my cereal (yes, breakfast cereal!). For the larger size tomatoes, I eat them like I would eat an apple, with tons of napkins on hand to handle their juices.

But when I was asked to write an article about home-canning tomatoes, I was at a loss. My only experience with canned tomatoes is the metal containers of stewed tomatoes, pre-made tomato sauce, and tomato soup that I buy from the grocery store. I enjoy their convenience and affordability. However, canned tomatoes taste good only after they have been mixed with a lot of other ingredients to make dishes like stuffed peppers, chili, and lasagna. Why would I ruin a beautiful tasty heirloom tomato by putting it into a can?

To learn more about the taste of home-canned tomatoes I reached out to Craig LeHoullier, a North Carolina gardener, author of The Epic Tomato and co-organizer for Tomatopalooza™, a tomato tasting event which was held annually for 10 consecutive years. Craig explained that the intense flavors of home grown heirloom tomatoes produce a great tasting canned product. The texture of the tomato changes but the flavor remains.

“We’ve kind of been conditioned to enjoy pretty ordinary tasting canned tomatoes – just like we’ve been conditioned to accept the awful taste of ‘grocery store’ tomatoes,” said Craig.  

Well, that’s great news that a home canned organic heirloom tomato will taste better than a store-bought canned generic tomato. But if I’m going to buy a canner, glass jars, and two piece lids and go through the trouble of learning how to home-can fresh fruits wouldn’t there be much more exciting things to can? It seems easier to continue buying bland canned tomatoes at my grocery store…

In an effort to give home-canning tomatoes a fair chance, I began researching the types of tomatoes and farming practices that go into making commercially canned tomato products. Tomatoes destined to be commercially-canned are called processing tomatoes. These Roma-sized tomatoes are bred to have thick skins with a dense, non-juicy, mealy consistency.

Despite the Italian-themed colors on the outside of store-bought canned tomatoes, the majority of U.S. canning facilities and tomato fields are in California. According to the Commercial Tomato Production Handbook (B 1312), after California, Indiana, Michigan, and Ohio are other major producers.

commercial-whole-canned-tomatoes (1)

Farming operations under contract with tomato processors have a narrow list of approved processing tomato varieties to choose from. In 2005, more than half of the California processing tomatoes belonged to only five varieties (Hartz et al, Processing Tomato Production in California). The reason for the lack in seed diversity is that the goal for processing tomatoes is high yields, disease resistance, uniform size, shape and color, as well as the ability to have 90% of the tomatoes in the field ripen at the time of harvest..


CFSA members believe that food you can trust starts at the source – with the farmer. Join CFSA’s Perennial Givers Guild and your monthly donation of any amount will help us grow local & organic from seed to plate.


U.S. farming operations grow processing tomatoes on a large scale, where tomatoes are mechanically harvested, and collected into bins that can hold between 800 and 1,200 pounds of fresh tomatoes. The fertilization, weed management and pest managements vary among growers and can involve the use of fertilizers, herbicides and insecticides (Hartz et al, Processing Tomato Production in California). Canning tomatoes occurs in 55 gallon drums and often involves a lot of added sugar and salt.

Tomatopalooza kristina bulgarian

I have to admit canning heirloom tomatoes at home is looking more and more attractive. But here’s the last selling point: by learning how to can local tomatoes you and I can play a vital role in reducing local crop loss and waste. Did you know there are times that it can be more expensive for farmers to harvest and sell their tomatoes than it is to leave them in the fields? This tomato loss happens when their supply is greater than the demand. And tomato waste has happened to the most enthusiastic tomato-eating customer. This occurs when the lovely tomatoes you have bought from your local farmer spoil before you have the chance to eat them.

But our heirloom tomatoes don’t have to spoil. By learning how to home-can tomatoes you and I will be able to preserve them at the peak of the freshness. Read Part 2 to learn how to can!

It is heartbreaking to see an heirloom tomato spoil. The demise of a delicious plump and firm tomato may begin with some parts of the fruit becoming darker than the rest. You may see white, green, or black-colored mold growing on the surface. The consistency gets mushy. Other tell-tale signs of a rotting tomato are when the skin becomes puckered and wrinkled, an oily looking liquid begin leaking out from the bottom of the tomato, and the smell becomes rancid and unpleasant.

In summary here are five reasons to home-can local organic tomatoes:

  1. Support local farmers in North Carolina and South Carolina: 90% of domestically commercially-canned tomatoes are grown and processed in California (Hertz et al. Processing Tomato Production in California)
  2. Promote seed diversity and tomato varieties: Unlike processing tomatoes, heirloom tomatoes are selected for their diverse sizes, shapes and colors.
  3. Reward small-scale organic farming practices: Choose to home-can tomatoes from local farmers that manage their pests and weeds organically.
  4. Improve the flavor of canned tomatoes and remove unhealthy ingredients: Commercially-canned tomatoes often come with excess amounts of sugar and salt and don’t have the delicious flavors of heirloom tomatoes.
  5. Prevent local heirloom tomatoes from being wasted: Read “Part 2: Home-canning Heirloom Tomatoes – a step-by-step guide with safety tips!” to prevent crop loss and food waste.

Ciranna Bird helps local farmers educate their customers on the health benefits related to small-scale pasture-based production of meat, dairy, and eggs. On July 21st, she will be presenting a workshop entitled “Protect your egg-laying hens and customers from Salmonella” at the Inter-Faith Food Shuttle. Registration is first come first serve. Information on her other speaking engagements, as well as her NC food blog, can be found at


William Terry Kelley and George Boyhan. History, Significance, Classification and Growth. In: Commercial Tomato Production Handbook (B 1312). University of Georgia. Re-published on Feb 5, 2010. Reviewed on Jan 4, 2014. Accessed June 15, 2015.

Hartz T, Miyao G, Mickler J, LeStrange M, Stoddard S, Nunez J, Aegerter B. Processing Tomato Production in California. University of California. Division of Agriculture and Natural Resources. Pg. 1