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I was very surprised to see an article in a recent publication toting the benefits of oven canning. With this method of canning hot food is put in canning jars, the lids tightened on and then the food jars are put in a heated oven to "can" them. IMHO this is just plain dangerous. "True home canning is when the food is heated enough to destroy or sufficiently acid enough to prevent growth of all spores of Clostridium botulinum (that causes botulism) and other pathogens during room temperature storage on the shelf." - The National Center for home Food Preservation
1) Risk of food poisoning. This method banks on the idea that an oven can get the internal temperature of the food in the jars hot enough to kill all and any bacteria in them. Actual oven temperatures can vary from the temperature setting on the oven control knob. There is a very real risk of a potentially deadly case of food poisoning from food canned in this manner. The food may look, smell and feel perfectly safe and still be deadly to ingest. Bacteria, especially in low acid foods can be harder to kill which is why a pressurized canner is requirement to can them.
According to The National Center for home Food Preservation:" Is it safe to process food in the oven?
No. This can be dangerous because the temperature will vary according to the accuracy of oven regulators and circulation of heat. Dry heat is very slow in penetrating into jars of food. Also, jars explode easily in the oven."
Link: http://nchfp.uga.edu/questions/FAQ_canning.html
2) Jars could be damaged. Scientifically glass is not described as a solid but as a rigid liquid. This is one reason why old window panes often look blurry. The "liquid" glass has been flowing downward over the years due to gravity. Putting glass in a heated oven may weaken it. I use to put my canning jars in a very low oven (200 F) to help keep them hot and sterile while I was getting the food ready for the water bath canner. Some of the jars began to develop the blurry patterns similar to those old window panes.
3) Jars can explode. Canning jars could do this because they were not designed for oven canning. Three reasons this could happen are: a) the pressure in the jar increases to a point where there is failure due to the heated food expanding or b) the pathogens in the jar were not killed as the food spoiled the pressure increased in the jar to the point of failure and/or c) prolonged exposure to the dry oven heat may cause weaknesses in the glass that may make it more prone to failure. Regardless flying glass can be dangerous. Cleaning up the mess is not fun either.
1) Risk of food poisoning. This method banks on the idea that an oven can get the internal temperature of the food in the jars hot enough to kill all and any bacteria in them. Actual oven temperatures can vary from the temperature setting on the oven control knob. There is a very real risk of a potentially deadly case of food poisoning from food canned in this manner. The food may look, smell and feel perfectly safe and still be deadly to ingest. Bacteria, especially in low acid foods can be harder to kill which is why a pressurized canner is requirement to can them.
According to The National Center for home Food Preservation:" Is it safe to process food in the oven?
No. This can be dangerous because the temperature will vary according to the accuracy of oven regulators and circulation of heat. Dry heat is very slow in penetrating into jars of food. Also, jars explode easily in the oven."
Link: http://nchfp.uga.edu/questions/FAQ_canning.html
2) Jars could be damaged. Scientifically glass is not described as a solid but as a rigid liquid. This is one reason why old window panes often look blurry. The "liquid" glass has been flowing downward over the years due to gravity. Putting glass in a heated oven may weaken it. I use to put my canning jars in a very low oven (200 F) to help keep them hot and sterile while I was getting the food ready for the water bath canner. Some of the jars began to develop the blurry patterns similar to those old window panes.
3) Jars can explode. Canning jars could do this because they were not designed for oven canning. Three reasons this could happen are: a) the pressure in the jar increases to a point where there is failure due to the heated food expanding or b) the pathogens in the jar were not killed as the food spoiled the pressure increased in the jar to the point of failure and/or c) prolonged exposure to the dry oven heat may cause weaknesses in the glass that may make it more prone to failure. Regardless flying glass can be dangerous. Cleaning up the mess is not fun either.