Preserving Tomatoes

By Patty Glenn Leander

Contributing Writer

‘Those rainbow jars of summer

Sparkling on the shelf—

Nature’s bounty captured there

With something of myself.’

—Mary MacDonald Stewart

When life gives you tomatoes, make salsa! And tomato sandwiches, roasted tomatoes, salads, BLTs, gazpacho — enjoy these fresh tomato pleasures because as the heat and lack of rain take their toll, the quality of the fruit will decline and most plants fall victim to pests and diseases that are increasingly difficult to keep in check. A great way to capture the summer flavor of a surplus of tomatoes at their peak is by canning, freezing or drying.

Putting up food used to be a necessary part of American life. “Eat what you can and can what you can’t” was a constant reminder to America’s citizens during tough economic times, including both World Wars and the Great Depression. After World War II, the importance of the victory garden slowly began to fade, and the convenience of processed foods, in all their glory, became the norm as women sought to escape the domestic drudgery of the kitchen. Hopefully that mass exodus from the kitchen and surrender of our food preparation to the industrial food chain was only a blip on our cultural radar. As each new generation comes of age, so does the realization that there is no substitute for home-cooking; and home-grown and home-made provides a primal sense of satisfaction and self-reliance, along with a deeper understanding of and connection to our heritage.

The recent vegetable gardening explosion has ushered in a renewed interest in canning, pickling and freezing, and fortunately there are a multitude of resources available to would-be preservationists. USDA’s 196-page publication, “Complete Guide to Home Canning,” can be viewed online at, or a print copy can be purchased for $18.00 through the Purdue University bookstore ( University of Georgia Cooperative Extension offers a self-paced online course on home canning and preservation, free of charge, at The classic Ball Blue Book, first published in 1909, has been revised and updated, and their 100th anniversary edition is now sold in kitchen stores and bookstores for less than $6.00. Heck, you can buy it at Wal-Mart, right next to the canning jars. Library shelves are full of books on canning and preserving, and your local AgriLife Extension office is also an excellent source of information.

Canning techniques have been refined through scientific research, but the basic principles have not changed much over the last century. Low acid foods, including vegetables and meat, are canned under pressure to reach a temperature that is high enough (240°) to destroy harmful microorganisms that can cause spoilage or diseases. Foods that are high in acid, defined as foods with a pH of 4.6 or lower (most fruits and tomatoes), or foods that are preserved with acid (like pickles, chow chow and relish) create an environment which inhibits bacterial growth and hence can be processed in the boiling-water bath method which requires the heating of foods to 212° — no pressure canner required. Tomatoes are generally considered a high-acid food; however their acidity is variable, so reinforcing them with a small amount of acid, usually in the form of bottled lemon juice or citric acid, is recommended in most recipes.

Preserving your produce does not improve quality, so if you decide to preserve your bounty, be sure to use ripe, clean, unblemished fruit for processing. Fortunately for tomato enthusiasts, freshly harvested tomatoes are also ideal candidates for freezing, oven-roasting and drying. Multi-purpose glass canning jars are my favorite container for putting up tomatoes as they can be used in the refrigerator, freezer, boiling-water canner and pressure canner. They are also the perfect shape and size for using an immersion blender, which is less cumbersome than a food processor or food mill, especially when working with smaller quantities. Heavy duty plastic bags and containers are also suitable for freezing. Be sure to label and date all containers before storing. In general, produce that has been preserved by canning or freezing should be used within 6 to 12 months.

Tomatoes can be frozen whole or halved, or can be made into sauce or juice before freezing. When frozen intact, they may lose their visual appeal, but freezing is the quickest and most convenient method of capturing that gratifying “I-grew-them-myself” flavor. Blanching to remove the skins is a matter of personal choice. If you are making sauce and don’t like those pieces of skin, then peel before cooking, but if you are freezing tomatoes whole, don’t worry about the skins. When it comes time to use them, just let the tomatoes thaw for a few minutes, run them under cold water and the skins will slip right off.

Plum or paste tomatoes, such as ‘Roma,’ ‘Viva Italia’ and the super-sized ‘Big Mama,’ are excellent choices for preserving because they are meatier and have a lower water content. They are suitable for sauces, roasting, freezing and drying. Beefsteaks and slicers can be used, but the roasting process will take longer and canned sauces tend to be more watery.

Cherry, grape and paste tomatoes are the best candidates for drying, which can be accomplished in a low oven, in the sun or in an electric dehydrator. If you live in an area with low humidity and moisture, you may want to try sun-drying thin slices of tomato outside on racks or screens. This method requires more time but only draws energy from the sun — and you! The sun-drying process can take up to 2 weeks and tomatoes must be moved indoors if there is any chance of dew or moisture in the night. They also need to be monitored regularly and may need to be covered with screen or cheesecloth if insects present a problem.

There’s always a little trial and error involved with oven- and sun-drying; for carefree and truly dried and crisp tomatoes, an electric dehydrator will yield more consistent results.


Big Mama



Viva Italia

Days to Harvest

80 days

76-80 days

60 days

75 days


1, 2, 5

1, 2, 4

1, 3, 4

1. W. Atlee Burpee & Co.

(800) 888-1447

4. Tomato Growers Supply Company

(888) 478-7333

2.Harris Seeds

(800) 544-7938

5. Willhite Seed Company

(800) 828-1840

3. Territorial Seeds

(800) 626-0866


You do not have to use a blender/food processor. If you prefer, finely chop the first five ingredients by hand, then stir in the seasonings and adjust to your taste.

4 fresh tomatoes, chopped (peeled and seeded if desired, but I usually don’t)

2-3 jalapenos, chopped

1 onion, chopped

1-2 cloves garlic, smashed

1/4 cup cilantro

1-2 teaspoon salt

1/2 teaspoon pepper

1/2 teaspoon cumin

2-4 tablespoon lime juice

1/2 teaspoon sugar

Chop the onion, jalapenos, garlic and one tomato in a blender or food processor. Then add the seasonings and the remaining tomatoes, and blend until it seems right. This is personal taste. You can leave it chunky, but I usually blend out most of the chunks. Then I taste and usually end up adding more tomatoes, lime juice and sometimes another jalapeno. I let it sit a bit and then go back and taste and adjust seasonings if necessary. It gets a little redder and a little spicier as it sits.

Tomato Sauce

If you have a prized tomato sauce recipe from a great-grandmother who came to America on a ship from Italy, by all means use it. Otherwise, here is a basic recipe to get you started — take it and make it your own. This sauce, made with fresh tomatoes, can be used the same day it is made or it can be frozen for later use.

4 tablespoons olive oil

1 onion, diced

2 cloves of garlic, minced

1/2 teaspoon red chile flakes

8-12 plum tomatoes, peeled and cored

2 teaspoon salt

1 teaspoon pepper

1 tablespoon sugar

2-3 teaspoons fresh oregano, basil and/or thyme, if desired

1 tablespoon butter

Place a sieve over a large bowl. Seed tomatoes over sieve, catching juices in bowl. Reserve juice, discard seeds and chop tomatoes. Sauté onions in olive oil for 5 minutes. Add garlic and red chile flakes and sauté 1-2 more minutes. Stir in tomatoes and seasonings. Simmer uncovered approximately 1 hour, stirring occasionally, and adding a bit of reserved tomato juice if necessary. Add butter at end of cooking. Pack cooled sauce into freezer containers, leaving 1 inch of space for expansion.

Canned Crushed Tomatoes

Crushed tomatoes are quite versatile — they can be used in sauces, soups, pasta and casseroles, and are suitable for freezing in lieu of canning. The recipe below explains how to prepare them using the boiling water-bath method. If you are canning in quart jars, you will need to invest in an inexpensive water-bath canner, but pint and half-pint jars can be processed in a large stockpot, as long as it is deep enough to cover the jars with 1 inch of water and wide enough to accommodate a rack so that jars sit 1/2” above the bottom of the pot. A plastic jar funnel with a wide opening will make the task of filling jars a breeze, and special tongs, called a jar lifter, allows you to safely submerge jars and remove them from boiling water. Before starting, gather all equipment and wash jars, lids and bands in hot soapy water. Immerse jars in simmering water of canner until ready to use and drop lids into a small pan of simmering water (do not boil lids as this may damage the seal).

6-8 pounds tomatoes

Bottled lemon juice or citric acid

Salt, if desired

To remove skins, blanch whole tomatoes in a pot of boiling water for 30 seconds. Remove with a slotted spoon and place into a large pan of ice water to cool. Peel off skin, core and halve tomatoes. Squeeze gently to remove seeds and excess liquid.

Quarter tomatoes and add a shallow layer to cover the bottom of a large pot. Bring to boil over high heat while crushing layer of tomatoes with a potato masher. Gradually add the remaining tomato quarters, stirring constantly to prevent scorching. Once all tomatoes have been added, boil gently for 5 minutes.

Remove jars from simmering water. Add 1 tablespoon of bottled lemon juice or 1/4 teaspoon citric acid to each pint jar and, if desired, 1/2 teaspoon salt. Double amounts if using quart jars. Ladle hot tomatoes into hot jars, leaving 1/2 inch headspace. Run a non-metallic spatula or chopstick around inside of jars to remove air bubbles, and wipe the rims with a clean, damp cloth. Place lids and bands on jars and screw until tight, but do not over-tighten. Use jar lifter to carefully lower jars into simmering water and place upright on rack, leaving 1 inch of space between jars. After all jars are in place it may be necessary to add more hot water to be sure that jars are covered by at least 1 inch. Bring water to a full boil, cover, and process 35 minutes for pints and 45 minutes for quarts. Remove jars from canner and set on dish towel or rack to cool. During cooling lids should make a faint pop when vacuum seal is complete; wait 12-24 hours before removing bands and checking seal. If the lid did not seal properly, refrigerate the tomatoes and use within a couple of days.

Quick-Freeze Tomatoes

Freezing tomatoes is like freezing blueberries — minimal preparation required. Tomatoes retain their flavor but lose their texture during the freezing process, so they are fine for cooked dishes like soups and sauces, but not so good for salsas or salads.

Wash and dry tomatoes. Larger tomatoes should be cut in half; smaller varieties can be frozen whole. Lay tomatoes on a tray or baking sheet lined with wax paper and freeze until solid, then remove tomatoes and place in clean canning jars, freezer bags or plastic containers. Label and place in freezer immediately.

Roasted Tomatoes

Roasting tomatoes brings out an amazing, concentrated flavor — they can be used in sauces, pasta, salsa, sandwiches or simply as a savory snack. They don’t last long around my house, but they can be stored in the refrigerator for 2-3 weeks or frozen for up to three months without compromising the flavor. This method works well with plum type tomatoes, including the popular variety ‘Juliet.’ Standard-size tomatoes may take 2 or even 3 hours longer.

24 plum tomatoes

6 tablespoons olive oil

1 clove of garlic, minced

Salt and pepper to taste

Minced herbs (I like to use oregano or thyme)

Wash, dry and core tomatoes. Cut in half lengthwise and gently remove seeds and excess pulp. Lay tomatoes cut side up on a foil-lined baking sheet. Mix garlic and olive oil. Drizzle over tomatoes and sprinkle with salt, pepper and minced herbs. Roast in a 325º oven for 1-1/2 to 2 hours. Tomatoes will look deflated and slightly charred. Some tomatoes may need to be removed sooner than others; some may take slightly longer.

Easy Oven-Dried Grape or Roma Tomato Slices

Thinly slice tomatoes crosswise. Arrange in a single layer on a parchment-lined, rimmed baking sheet. Drizzle or brush slices with olive oil. Sprinkle with salt and pepper. Roast at 175° for 1-1/2 to 2 hours. Store up to one week in the refrigerator or cover with olive oil and refrigerate up to one month. When tomatoes are gone, flavored olive oil can be used for salad dressings and marinades.

Oven-Roasted Cherry Tomatoes

Cherry and grape tomatoes are especially delicious when roasted whole.

Toss whole cherry or grape tomatoes generously in olive oil, season with salt and pepper, and roast 4-6 hours at 300°. Store 2-4 weeks in the refrigerator or eat them all as soon as you take them out of the oven.


—Ultimate tomato flavor comes from tomatoes that never see the cold, especially the inside of a refrigerator. It is preferable to store tomatoes at room temperature, but like most vegetables their life can be prolonged under refrigeration. If you must resort to this step, allowing them to sit at room temperature for 24 hours before consuming will help recover some of that fresh flavor.

—Tomatoes get their red color from an antioxidant called lycopene, and studies have shown that lycopene is more readily absorbed when tomatoes are cooked, especially when combined with oil or fat.

—Harvest tomatoes in the morning for best quality and flavor, and process as soon as possible after harvest.

—For drying and roasting, remove seeds and cut tomatoes into uniform slices for more consistent results.

—Date and label all containers before storing.

—For best results, use freshly harvested, unblemished tomatoes, and follow recipe directions carefully.

—Canning jars and bands can be used multiple times, but lids may only be used once for a proper seal.

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