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OSU Extension

College of Food, Agricultural, and Environmental Sciences

August 21, 2017 - 10:02am -- Anonymous

It’s the end of summer and the end of the canning season.  I’ve had many phone calls and conversations as I’ve been testing pressure canners this week, below is a quick list of the most common questions I’ve received:

*How tightly should the ring bands be put on when closing jars with two-piece lids?

     Fingertip tight or if you want to be more precise, one inch past the point of first resistance.  Putting the ring on too tightly may cause the lids to buckle.

*Can food be reprocessed if it was incorrectly processed or if the lids failed to seal?

     If it’s within 24 hours, you may: refrigerate the food and use within two days, freeze the food (allow headspace in the jar for expansion of the food and drain the vegetables) or reprocess the food using the same processing time and a new lid. 

*Can I use my pressure cooker or saucepan for home canning low-acid foods? 

     No, they are not recommended for canning.

*Why is liquid lost from glass jars during processing? 

     The most common reasons for loss of liquid are packing jars too full, packing food too tightly into jars, changing pressure in a pressure canner or lowering pressure too suddenly.  If all air bubbles are not removed from jars before processing, the liquid may be lower in the jars after processing.

*Why does fruit float in the jars? 

     It may float because the pack is too loose or syrup too heavy or because some air remains in the fruit after heating or processing.

*Can I use tomatoes that are from dying vines?

     Remember to use only disease free, fresh fruit.  Do not can tomatoes from dead or frost killed vines.  All types of tomatoes can be processed, green, yellow, orange or red and for best results process the tomatoes within 2 to 3 hours of harvesting. 

*Do all tomatoes need to be acidified?

     Yes- all tomatoes and tomato juice need to have additional acid to ensure their safety.  You may use lemon juice, citric acid or vinegar to do this.  Check out our (food, then food preservation) to find the canning tomato fact sheet that will give you the amounts for each.

*May I can whole cherry or grape tomatoes?

     It is not advised by USDA, but they may be frozen for use in soups and stews this winter

*How many pounds of tomatoes does it take to make 7 quarts of juice? 

     About 23 pounds of tomatoes are needed per canner load of 7 quarts; 14 pound will yield 9 pints.  If you are buying or picking a bushel of tomatoes it should yield about 15-18 quarts of juice.  Remember to add acid to your juice as well.

*Do I have to add salt?

     The use of salt is optional in all canned tomato products.  Salt can be used for flavor or color protection of the product.

*Can I process my grandmother’s spaghetti sauce recipe? 

     If you really want a specific recipe, then freeze it.  Only tested, approved recipes should be used to can low acid vegetables and meats.  Besides Ohioline check out the National Center For Home Food Preservation web site at the University of Georgia for a great library of tested recipes.  It is really important not to alter the tested recipes as it will change the ph. value and thus the processing times. 

If you have home canning or freezing questions that you want answers to, give me a call at 330-264-8722.  Happy Harvest!