Backyard Gardener: Canning tomatoes

Aug 31, 2023

Sep 1, 2023

(Photo Illustration/MetroCreative)

Hello Mid-Ohio Valley farmers and gardeners! September has arrived along with college football season, back to school and the fall harvest.

I am dedicating this column to my cousin Kim Barrett, who passed away Aug. 20. Kim was an avid gardener, including working in her community garden in Columbus, Ohio. She loved growing tomatoes, and her favorite was Mr. Stripey.

This week let’s talk preserving tomatoes. Many backyard gardeners across the valley are harvesting America’s favorite garden vegetable. Salads, sandwiches, and fresh eating are just a few of the uses for tomatoes. My two favorites are on grilled burgers and the famous tomato sandwich. This brings up a mayonnaise or miracle whip debate.

Mayonnaise is made of oil, eggs, and vinegar or lemon juice. Miracle Whip has the same basic ingredients but with less oil, and the addition of water, sugar, and spices like mustard, paprika, and garlic. Miracle Whip has less calories (due to half the fat) and is sweeter. I enjoy either one, depending on what’s in the fridge.

If you now have a huge harvest of tomatoes, you can always process them and make salsa, pizza sauce, whole and crushed tomatoes, as well as the famous home canned tomato juice. Tomato juice is low in calories and packed with nutrition including B-vitamins, vitamin c and potassium.

Canning, drying, freezing, salting and fermenting are some of the methods used. Tomatoes are one of the most commonly canned vegetables and many recipes have been handed down from generation to generation in many families.

My grandmother would can hundreds of quarts of tomato juice to store in the basement of their house. I am sure many people around the area have similar memories of canning and preserving the harvest with family to be enjoyed throughout the year.

Proper methods, choice ingredients and awareness of acidity levels are critical to a safe home-canned product. Tomatoes vary in their acidity. For this reason, all tomatoes must be acidified before canning to prevent botulism, a potentially deadly illness caused by a toxin produced during growth of the bacterium Clostridium botulinum.

Only boiling water or pressure canning methods are recommended for canning tomatoes. Older methods, such as oven canning and open-kettle canning, have been discredited and can be hazardous.

The risk of botulism poisoning determines the choice of either boiling water or pressure canners for canning foods. In acid foods (pH 4.6 or lower) the microorganism that causes botulism cannot grow. Therefore it is safe to use a boiling water bath canner. All other foods must be canned using tested pressure canning processes.

Unfortunately, there are many canning recipes that are inadequate to kill all spoilage microorganisms. Canning recommendations for tomatoes have changed over the years so be sure you follow the most up to date guidelines when canning tomatoes.

Although tomatoes have a tangy acidic taste, precautions must be taken to can tomatoes safely as they are considered borderline between a high and low acid food.

Here are a few recommendations for preserving a safe, nutritious and delicious homemade tomato product.

Make sure you acidify the tomatoes. Add bottled lemon juice or citric acid to each jar before processing. To assure a safe acidity level, place 2 tablespoons bottled lemon juice or ¢ teaspoon citric acid crystals in the bottom of each quart jar before filling with the tomato product.

Use half those amounts when canning in pint jars. Other tomato products should also be acidified. Some catsup and barbecue sauces do not need to be acidified because they contain large amounts of vinegar that provides the needed acidity. If in doubt, add the lemon juice or citric acid.

Processing time depends upon the method of pack and added ingredients. Tomatoes may also be processed in a pressure canner. Please follow the recommended process time, adjusted for altitude, for the product you are making.

Do make sure you process long enough. Processing times have increased over the years. For processing times and information relating to canning and preserving check out The National Center for Home Food Preservation website at nchfp.uga.edu.

Match the type of tomato to the product being canned. Regular tomatoes work well for juice and canned tomatoes. Paste, plum and Roma varieties are good for making sauce, salsa, catsup, and purees. The two types can be mixed.

Follow the same directions for canning low-acid or yellow tomatoes as are recommended for regular tomatoes. Although low-acid tomatoes don’t taste as sour, their acidity is masked by the natural sweetness of the variety; no changes are needed in the recipe for safety.

Always use high quality tomatoes. Some growing conditions may cause the tomatoes to be unsafe to can even when the tomatoes look fine. Tomatoes with blight and those from dead or frost-killed vines may be lower in acidity and are more likely to carry bacteria.

Do not can using the open kettle method. Do not just heat the tomatoes or tomato product and pour the hot product into the jars, add the lids, and wait for the lids to “pop” without any further processing.

Even though the jars may seal, the contents inside the jars have not been heated adequately to destroy harmful spoilage organisms.

Do not make up your own recipes for canning salsa, spaghetti sauce, pizza sauce, etc. All these foods have added low acid ingredients for flavor. Use up-to-date scientifically research-based recipes.

Tomato products with added vegetables or meat require pressure canning. Do not add extra low acid ingredients to canning recipes. Measure ingredients accurately and do not add extra peppers, onions, garlic, or other vegetables for flavor in a tested recipe.

Add no more than three cups in any combination of finely chopped celery, onions, carrots, and pepper for each 22 pounds (the amount for seven quarts) of tomatoes when making tomato-vegetable juice blends. It is safe to reduce or omit a low acid ingredient such as garlic in a tomato sauce recipe.

Some people love stewed tomatoes. Do not add thickeners or milk to tomatoes or tomato products before processing. Add the ingredients to make stewed tomatoes or tomato soup when you are ready to serve them.

Use only standard canning jars. Packer’s jars from commercially canned foods you purchase at the grocery such as mayonnaise, peanut butter and jelly may break in the canning process or may not seal. Use new lids too.

After processing, use a jar lifter to carefully remove jars from canner and place on rack, dry towel or newspaper, leaving at least 1? space between jars. Allow jars to cool untouched, away from drafts, for 12 to 24 hours before testing seals.

To test jar seals, press lids at the center. They should be slightly concave and not move. If sealed, remove screw bands. Label sealed jars with contents, canning method and date. Store in a clean, cool, dry, dark place. If not sealed, the product must be reprocessed, refrigerated, or frozen immediately.

A few more word of advice from the WV Extension Publication “We Can Tomatoes”. Select only disease-free, preferably vine-ripened, firm fruit for canning. Do not can tomatoes from dead or frost-killed vines. Green tomatoes are more acidic than ripened fruit and can be canned safely with any of the recommendations for ripened tomatoes.

Tomatoes may be canned with a boiling-water canner or a pressure canner but a pressure canner gives a higher quality, more nutritious product.

To give you an idea of how many pounds of tomatoes it takes to make juice on average, 53 pounds (1 bushel) yields 15 to 18 quarts, 23 pounds yields a canner load of 7 quarts, and 14 pounds yields a canner load of 9 pints. My Grandma figured 52 weeks in the year, 2 quarts of tomato juice per week, so they need 104 quarts of tomato juice per year for the family.

Contact me at the Wood County WVU Extension office at (304)-424-1960 or at [email protected] with your questions. Until next time, Good Luck and Happy Gardening!

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