Donít Try This at HomeBy Paul Rodman (paulgrow)
October 16, 2013
Canning can be fun, save you money, and a convenient way to store food for cold winter months and even a great family activity. Canned food can also be safe or unsafe, depending on how it is processed. Some methods that have been determined to be unsafe and are NOT recommended include steam canners, solar canning, oven canning, open-kettle canning, microwave processing, and dishwasher processing. Do not put your family's health and the quality of your food at risk for the sake of a shortcut. Be sure to only use research-based methods and tested recipes for safe home food preservation. One of the most reliable sources for information is the Ball Blue Book.
Do not confuse steam canners with steam pressure canning. Steam canning uses a covered, shallow pan and rack to circulate steam around filled jars. Steam in this type of canner is not pressurized and does not maintain a steady flow of steam, or an even or consistent temperature. There are several brands on the market.
The manufacturer claims this process uses less water, saves time and energy, and recommends the same processing times as those required for boiling-water bath treatments. Studies have concluded atmospheric steam canners result in significantly lower product temperatures at the beginning and end of the scheduled process when compared to water-bath canning.
Use of steam canners as instructed by the manufacturer would result in under processing and considerable economic spoilage. Steam canners have not been tested by research based reliable sources, and cannot be recommended.
There are several reasons not to use your oven to can your food. For starters, the glass jars are not designed to withstand the intense dry heat and may shatter in the oven. There is also the danger of breakage and burns while removing them from the oven.
Also, and most importantly, the transfer of heat into the jars is much slower through air in an oven than in a water bath or a pressurized steam canner. Traditional canning recipes have been scientifically tested using a water bath or pressure canner and should be followed exactly as written. Otherwise there is a heightened risk of spoilage, or worse, survival of Clostridium botulinum spores, the source of deadly botulism poisoning. Besides the food poising aspect:
- Jars may explode when the oven door is opened.
- You or anyone nearby can be seriously cut or burned if a jar explodes.
- Your oven can sustain serious damage if jars explode.
- There is no available reliable research based information as to how long or what oven temperature to use.
Open kettle canning
I expect this method to elicit the most comments as this method is probably used by most home preservers than any of the other unsafe practices. Since the late 1980s, extension educators have been teaching that open kettle canning is no longer safe. Gradually, home food preservers are abandoning this practice and moving to processing all canned goods. Some educators have found that many young people may not even know about open kettle canning.
Open kettle canning involves heating the food to boiling, pouring it into the jars, applying lids, and allowing the heat of the jar to cause the lid to seal. Many years ago, it was commonly used for pickles, jams and jellies, and sometimes used for juices, tomatoes and applesauce. The reason open kettle canning is no longer recommended is that the food is not heated adequately to destroy spoilage organisms. Molds and yeasts can enter the jar while you are filling the jar; processing heats the head space of the jar destroying them. Instead, process jars in a boiling water bath or in a pressure canner to make sure they are adequately heated and to drive air out of the jar and form a strong vacuum seal.
Open kettle canning is not safe! It is especially dangerous when used for canning tomatoes or tomato products where the acid level may be low enough to allow bacterial growth. And never use open-kettle canning for low acid foods such as meats, vegetables and soups that must be pressure canned.
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. Many people are under the incorrect assumption that once a vacuum is formed, no germs can live in there and no spoilage can occur. Wrong, wrong, wrong!
For the life of me I don't know why someone would even want to try this. A dishwasher is great for washing and sterilizing your empty jars before canning. But this method involves putting food into jars, sealing them, and then "cooking" them in the dishwasher. The temperature of the water during the washing and rinsing cycles are far below those required to destroy microorganisms. The food would be under-processed and unsafe.
Microwave oven canning
The microwave oven has become the workhorse of most kitchens. We use it for everything from popcorn to prime rib; but canning food is something that should never be done in a microwave. Home-canned food can reach a safe temperature of 212-degrees Fahrenheit when heated in a microwave. So the reason why you shouldn't use this home canning method isn't because of low temperature. Rather, it's dangerous because the heat isn't evenly distributed, leaving cold spots in the food. Also, the canning jars can explode inside the microwave, and when they are taken out. Enough said, do not can in your microwave.
This involves putting food into jars, sealing them, and then cooking them in a solar oven. The temperatures don't get hot enough and the cooking is also uneven. Not safe, not reliable.
Please, please be safe in your canning. Properly done, you can stock your pantry full of safely preserved, delicious fruits, vegetables and meats that have a shelf life of approximately a year. They'll be completely safe to eat. When you take shortcuts with your canning, you are potentially taking shortcuts with your own life.
THERE ARE ONLY TWO SAFE METHODS OF CANNING FOODS:
- Boiling-water bath canning - where you pack HIGH ACID FOODS (like fruits, jams/jellies, pickles and some tomatoes), either raw or cooked according to directions, into jars, seal, and boil in water for a specified time.
- Pressure canning - where you pack LOW ACID FOODS (like vegetables, meats, and soups), either raw or cooked according to directions, into jars, seal, and process under pressure for a specified time.
Pressure Canner Water Bath Canner