Do you enjoy the fresh taste of tomatoes just off the vine and still warm from the sun? Nothing reminds you more of summer than home-grown tomatoes. This is the vegetable we long for most when supermarkets offer less flavorful tomatoes grown in greenhouses.
If processing tomatoes with citric acid or lemon juice added is not part of your tomato canning procedures, you need to update your canning information. Tomato processing procedures have changed over the past few years. Tomatoes are considered a high acid food but the amount of acidity can vary according to type. The latest recommendations from USDA include adding acid and processing some packs of tomatoes 85 minutes in a boiling water bath. If you are using a pressure canner, call us for the preparation procedures and processing times.
Other recommendations for home canning from USDA include:
— Sterilizing jars in boiling water for 10 minutes if not processing foods for 10 minutes or more.
— Pre-treating lids according to manufacturer’s recommendations. Lids are often simmered before using. However, some lids require different pretreatments.
— Processing high acid foods (jellies, fruit and pickles) in a water bath canner according to tested recipes. This kills molds and other spoilage organisms that can grow during storage. Using paraffin for jellies is NO longer recommended.
— Processing low acid foods (vegetables including green beans, meats and seafood) in a pressure canner according to tested recipes. This kills spoilage organisms and bacteria that cause botulism.
— Venting all pressure canners 10 minutes before the weight is put on the vent pipe or the petcock is closed. Venting means allowing steam to escape from your canner through the vent pipe. This is important for driving air out of the canner so that you can reach the 240 degrees needed to kill harmful bacteria.
— Removing air from the jars before applying lids. Use a rubber spatula or a plastic “debubbler” available where canning supplies are sold. A metal knife or spoon may weaken jars so they crack during processing. Removing air helps ensure that your food is processed at temperatures high enough to kill harmful bacteria.
— Reprocessing jars that do not seal within 24 hours. Always use new lids and re-process for the full amount of time recommended in the recipe. The quality of the food will be lower, but it will be safe. Alternatives to reprocessing are to refrigerate the food and use in 1 or 2 days or freeze it.
Here a few other tips for successful canning: The best way to peel tomatoes is to dip them in boiling water for 30 to 60 seconds; then dip them in cold water to split the skins. The skin should slip off. Hint: If you cut a small “X” on the bottom before dipping, it helps them split more easily.
To ensure safe acidity in whole crushed or juiced tomatoes, add two tablespoons of bottled lemon juice or ½ teaspoon of citric acid per quart of tomatoes. For pints, use one tablespoon bottled lemon juice or 1/4 teaspoon citric acid. Add the acid to each jar rather than adding to the entire batch of tomatoes.
Adding other vegetables lowers the acidity of tomatoes, which can provide a favorable environment for the growth of bacteria that cause botulism. This product would require the pressure canner method of processing and use of tested recipe.
If you have food preservation questions you would like addressed in the “Home Canner’s Column,” call your local office of University of Tennessee Extension-Bradley County at 728-7001.
The Bradley County Cannery is opened by appointment by calling the facility at 728-7031. They are open Tuesday through Friday and look forward to your questions.