Flippin’ jelly! It sounds like a curse of sorts, doesn’t it? Maybe something you would say when the jelly you made doesn’t set up to the right consistency. In fact, flipping jelly is an old-school canning technique that involves pouring very hot jellies or jams into jars, tightening the canning lid, and turning the cans upside down on a towel for 5 minutes or so. After the five minutes or so, you flip the jars right side up and allow them to cool and (in theory) ping. The fancy term for it is inversion canning. It’s also occasionally referred to as open kettle canning.
Some things are great to pass down through the generations. Grandma’s world famous apple pie filling recipe is something to cherish. Some of her preservation techniques should, however, be left in the past. Times, they are a-changing.
Inversion canning was a common method for preserving pickles, jams, jellies, applesauce, and even (shuddering) tomato sauces.
Why is jelly flipping canning dangerous?
When jelly flipping/open kettle canning/inversion canning, food is cooked in an ordinary sauce pot, then packed into hot jars and sealed without processing. The temperatures obtained in the cooking process 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 sauce pot to the jars and cause spoilage.
The scary part is that I am seeing on canning forums that people are forgetting steps like sterilizing jars first. Yes, you can forget to sterilize with water bath canning and it’s not the end of the world. The can is boiled for so long that it self-sterilizes. With inversion canning, it’s dangerous as heck. Can you identify food spoilage before it grows fur? See more about home canning safety. I worry about some of these people that are just getting started and they are starting with this method.
According to Penn State Extension…
Just because a lid “pops,” it doesn’t mean the contents inside the jar are safe. The time saved with open kettle canning is not worth the risk of food spoilage or illness.
Since the 1980s, community extension offices have been urging canners to discontinue this practice. Still, advice on the technique abounds. The worst part is that it’s most common in jelly and jam making, which is the food most susceptible to mold growth. Mold lowers the pH of the food. A low pH allows for the botulism toxin to be created. See where I’m going here…
It should also be mentioned that today’s canning lids are not made to seal in this manner. They are made to vent under extreme heat. If you manage to heat your jelly and jam enough to kill all bacteria and micro-bacteria, the canning lid may cause the can to vent.
Additional Scary Canning Techniques
Although I am focusing my attention on flipping jelly to can it, there are a few additional canning techniques that should be left in the past. These include…
- Paraffin Wax Sealing involves pouring thin layers of wax over your jams and jellies until it is about 1/2″ thick. These wax seals do not remove the air in the can and frequently separate from the sides of the can, opening it up to bacteria.
- Steam Canning (not the same is pressure canning with steam) involves a small steamer that holds only an inch or so of water at the bottom. You put in your cans and close the lid and steam the cans. Unfortunately, the pressure doesn’t get strong enough to vacuum seal the cans and the temperatures don’t get high enough to sterilize.
“Information available on steam canners to date is contradictory. In the mid-1980’s Dr. Von Mendenhall at Utah State University did some research for a Salt Lake City steam canner manufacturer. In a personal letter (1986), he wrote that, based on research at Utah State and the University of Massachusetts, steam canning is safe for high acid foods only (fruits, jams, and jellies). However, there is no indication that his work was published or that it was reviewed by his peers.” (Clemson Extension Program)
“Due to the lack of definitive research into the safety of steam canning the Utah State University Extension program currently agrees with the present USDA and National Center for Home Food Preservation recommendation against using Steam Canners.”(Utah State University Extension Program)
- Aspirin Preservation involves adding aspirin tablets to low acid foods in the belief that they can be safely water bath canned instead of pressure canned.
- Oven Canning is something I am seeing way too much of lately. It involves using dry heat to can. There are two flaws with this. First, cans aren’t meant to be exposed to high levels of dry heat. There is a high risk of explosion. Second, dry heat takes an extremely long time to reach the middle of the can. The risk of the middle not getting hot enough to kill bacteria is too high.
Do yourself a favor and get the Ball Blue Book: Guide to Preserving and always keep the newest edition on hand during your canning adventures. If you are ever in doubt about a canning method or practice, check with your local cooperative extension office. They are a valuable resource.