Just as the tomatoes in your garden grow and the varieties of tomatoes in markets continue to increase in number, we also encounter a generous assortment of directions for canning tomatoes. But canning your tomatoes does not have to be too complicated, if you simply use reliable, research-based directions for preparing and processing your food.
For example, home canned tomatoes may be crushed so that they are ready-to-use, or left whole or halved. Whole or Halved Tomatoes may be canned with water, in tomato juice, or with no added liquid. While the no-added-liquid version of canned tomatoes is a raw pack, Crushed Tomatoes are a hot pack only. Tomato Juice can be made as is or as a Tomato-Vegetable Juice Blend, as hot packs only. Also only available as a hot pack is Tomato Sauce. Many more classic canned tomato product directions are available, such as Spaghetti Sauce with or without meat and Ketchup.
No matter how you choose to can your tomatoes, remember that it is very important to use a canning process time that matches up with the preparation directions for filling your jars. Also, it is important to the safety of your canned tomato products to use tested directions, like those from USDA. For many of these tomato products, there are canning options for both boiling water and pressure canning available in our directions.
In the case of these tomato products with both options, the pressure processing still requires acidification in these products. The pressure options only provide the same amount of heat to the product as the boiling water processes. Just because pressure is used to decrease the process time, the canning process is not the same as one to destroy spores of Clostridium botulinum as you would expect for low acid foods.
Tomatoes are borderline in pH between acid and low acid foods, so the USDA preparation directions for these products call for acidification to allow a less severe heat treatment than would be required without it. 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. (Citric acid results in a less noticeable change in taste for most people.) For pints, use one tablespoon bottled lemon juice or ¼ teaspoon citric acid. Acid can be added directly to the jars before filling with product; in fact, this is recommended to be sure you get the acid in each and every jar. Sugar may be added to offset an acid taste, if desired, but the acid cannot be decreased to taste. (Four tablespoons of a 5 percent acidity vinegar per quart may be used instead of lemon juice or citric acid. However, vinegar may cause undesirable flavor changes.)
The National Center for Home Food Preservation has recommended directions for canning tomatoes and tomato products under “How do I”….”Can”…..”Canning Tomatoes and Tomato Products“.
This entry contains excerpts from an article called “Sorting Out Tomato Canning Directions” written by Elizabeth Andress, PhD and Director of the National Center for Home Food Preservation.