freshare.net
By University of Mo. Extension
07-25-2008It is that time of year when the pressure canner comes out and foods are preserved for winter.
Both new and seasoned home canners have questions this time of year according to Tammy Roberts, nutrition and health education specialist, University of Missouri Extension.
Listed below are some of the most common questions Roberts has received this year followed by her answer.
Q. How should I store home-canned foods and for how long?
A. The recommendation is that you use home-canned foods within one year. To store, a dry dark place between 50 and 70 degrees is best.
Q. How often should a pressure canner gauge be checked?
A. The dial gauge should be checked every year. An accurate gauge helps to ensure the safety of the home-canned foods.
Q. I have lots of mayonnaise jars on my shelf. Is it safe to use them for home canning?
A. It is not recommended. These jars break more easily in a pressure canner.
Q. The house gets too hot when I can inside. Can I do it on the camp stove outside?
A. It is not recommended that you use the camp stove, kerosene stove or turkey fryer as a source of heat for canning. The heating patterns are hard to maintain making it hard to maintain the proper pressure for a safe product.
Q. Why do I lose liquid from the jars when I am canning?
A. That can happen for several reasons. One is that the jars may have been packed too full and the liquid boiled out of the jars during processing. Another reason is that temperatures may have been fluctuating during the canning process. This can happen while turning the temperature up and down to adjust pressure. A common reason this occurs is because the pressure was lowered too suddenly.
Q. Can I run cool water over the canner to speed the cool down process?
A. The cooling process is an important part as bacteria are still being destroyed at this time. Cooling the canner can result in food being under processed and the possibility of bacteria surviving. Rapid cooling causes a change in pressure that draws the liquid out the jars.
Q. Why do lids buckle after processing?
A. Buckling occurs because the screw band was too tight. The screw band should be tightened firmly by hand but not forced to the tightest possible seal. If the lids have buckled during processing, the foods should be refrigerated and used within one to two days or reprocessed.
Q. How tight should the lids be screwed on then?
A: Unlike lids of years ago, new lids require a lighter touch when closing the jar for canning. Some time ago, major canning lid companies redesigned their lids. Lids today need only be screwed on gently.
Q: Should I boil or sterilize the lids before using them?
A: Although it is important to keep items used for canning clean, it is not a good idea to boil canning flats to sterilize them. The sealing compound used these days will soften when boiled. With this change happening prior to the actual canning process, when the lids on the jars are then processed at canning temperatures, they will form a seal prematurely. Buckling occurs and food is spoiled.
Q. What is “headspace” and why is it important to be precise with it?
A. Headspace is the amount of space between the top of the jar and the ingredients in the jar. If you don’t leave enough headspace, contents of the jar can boil over and leave particles on the rim. That prevents the jar from sealing properly. If too much headspace is left, air may remain in the jar after processing which causes food at the top of the jar to darken.
Q. Can I process two layers of jars in the canner at one time?
A. Yes, if your canner is tall enough. Place a wire rack between the two layers of jars to allow the water or steam to circulate around all jars and then process according to timetables appropriate for the food you are canning.
Q. I cooked my salsa for four hours, is there any need to process it?
A. The days of putting a hot liquid in the canning jar that causes the jar to seal are over. All home preserved foods should be processed. Tomatoes, fruit and pickles can be processed in a boiling water canner with the jars covered with one to two inches of water for a specified amount of time. All other vegetables, meat and dairy products should be processed in a pressure canner to ensure safety.
For salsa, University Extension recommends that only tested recipes be home canned and that processing directions be closely followed. If using a recipe not tested, salsa can be frozen with good results.
MORE INFORMATION
For more information contact Tammy Roberts at (417) 682-3579 or contact the nearest MU Extension Center for a copy guide sheet, “Steps to Success in Home Canning GH 1452.”