Looking for Do I Need to Use a Canner for Jams, Jellies, Salsa, Pickles, and other Home Food Preservation? in 2020? Scroll down this page and follow the links. And if you bring home some fruit or vegetables and want to can, freeze, make jam, salsa or pickles, see this page for simple, reliable, illustrated canning, freezing or preserving directions. There are plenty of other related resources, click on the resources dropdown above.
People occasionally ask, "why use a water bath method or a pressure canner. My grandmother used and she never got ill!" That may be true, just as there are occasionally smokers who live to 100 or people who cross the street without looking and don't get hit by a car. But no rational person would recommend these either...
The US Department of Agriculture and many major universities (Clemson, University of Georgia, University of Illinois, University of Wisconsin, University of Minnesota, to name a few; click here for links to the references, at the bottom of this page) l have each extensively studied food safety and home canning. To summarize their findings; all of them state that if you are canning at home, including making jams and jellies, you must use a water bath or pressure canner, if you want to avoid food poisoning. By food poisoning they are referring to varieties of bacteria, such as botulism, that grow in a sealed environment. Without hyperbole, death is one of the outcomes of such poisoning. See this page for detailed information about botulism food poisoning.
Some recipes, particularly old family recipes and many floating around on the internet don't call for processing. The food is cooked in an ordinary pot or kettle, then packed into hot jars and sealed without processing (this is called the "open kettle method").. The temperatures obtained in open kettle canning are not high enough to destroy all spoilage and food poisoning organisms that may be in the food. Also, microorganisms can enter the food when it is transferred from the kettle to jar and cause spoilage. These are obsolete and may be dangerous. According to the USDA;
"Canning recipes prior to 1990 should not be used. Many old recipes do not include instructions for processing foods. The foods are canned by the open kettle method, sealed and stored. This method for canning, the open kettle method, is not recommended for it presents a serious food safety hazard. All high acid foods should be processed in a water bath canner and all low acid foods in a pressure canner. "
Were he alive, Louis Pasteur would tell you that at the time you sealed the jars, the temperature of the contents had already dropped way below 212 F. Meanwhile, the jars were exposed to the air (temp 70f to 90 F) which is not a sterile environment and does contain floating spores of Clostidium Botulism and other harmful bacteria. Therefore, the sealed jars now contain small amounts of live lethal bacteria.
Also, microorganisms can enter the food when it is transferred
from the kettle to jar and cause spoilage. (Surprisingly to some, the air in
your kitchen is not sterile).
Over time, those spores would grow. Typically, some bacteria grow that consume remaining oxygen and create an environment ideal for Clostidium Botulism to then grow as a secondary bloom. How fast and to what extent, is subject to many variables, but how many of us want to play Russian roulette with our health and food?
Water bath processing would kill the vast majority of those spores, creating a sealed sterile environment. Does this help explain it in terms that even Grandma would grasp? :)
Equipment for heat-processing home-canned food is of two main types--boiling-water canners and pressure canners. There are many other types which are NOT recommended by the authorities (see this page for more about obsolete and unsafe canning methods)
Most are designed to hold seven quart jars or eight to nine pints. Small pressure canners hold four quart jars; some large pressure canners hold 18 pint jars in two layers, but hold only seven quart jars. Pressure saucepans with smaller volume capacities are not recommended for use in canning. Small capacity pressure canners are treated in a similar manner as standard larger canners, and should be vented using the typical venting procedures.
You can also find free information about canners from the USDA in this PDF file (it will take a while to load!) about selecting and using canners here!
Q. I have never been able to get a straight answer about whether adding lemon juice or vinegar is necessary if canning salsa in a pressure canner. It would seem to me that you would not need to add the vinegar or lemon juice because you would be bringing up the temperature and maintaining it at high points that would kill off any botulism spores. This would seem to me to be similar to what you do when you safely can your own tuna in a pressure cooker. Can you please provide an answer to this question?
A. Yes, it is necessary! It's more complicated than that!! No process, of any kind, kills ALL spores, so part of the equation is; to what extent is the population of spores diminished, and what will be the replication rate of those that survive? Pressure canning, using high temperatures destroys more spores than water bath canning, and commercial conning equipment destroys a far, far greater percentage of the resident spores than any home method. The addition of acid inhibits the remaining spores growth, keeping the levels of bacteria (which are always present) to a level that is effectively, undetectable and not a threat. Of course, if you store ANY canned food (home or commercial) long enough, it WILL spoil! That's why they're stamped with expiration dates!
See this page for more Answers to Common Questions About Home Canning, Freezing and Making Jams!
Who Invented the Canning Jar? Does Ball still make jars? - See: