PRESSURE CANNING VS. BOILING WATER BATH

You may have heard the terms "Hot Water Bath" or “Boiling Water Bath” and "Pressure Canning” when you are looking into preserving foods at home, but do you know the difference? If you plan to can fruits, vegetables, or meats you will be using both methods. The following is a quick overview on both types of canners.

Whether you are preserving high acid or low acid foods, it is important to read through the instructions and recipe, assembling all needed ingredients and cookware before beginning any canning or preserving process.

High acid foods can be preserved using a Boiling Water Bath. Acid foods include: Jellies, Jams, Marmalades, Fruits, Tomatoes (with added acid), Pickles, Relishes and Chutneys. Because Clostridium botulinum spores do not grow in the presence of acid it is safe to can high acid foods using the Boiling Water Bath method. The canner should be deep enough to allow at least 1 to 2 inches of water to boil over the jar tops. It must have a tight-fitting lid and a rack to keep jars off its bottom.The temperature of boiling water is 212 degrees Fahrenheit this can temperature is achievable using the Boiling Water Bath method of canning. 

When preserving vegetables, meats, seafood – low acid foods you will require a Pressure Canner. Low acid foods include: Vegetables, Meats, Poultry, Seafood, and combination Recipes (those that include low acid and high acid ingredients.) These foods MUST be heat processed at 240 degrees Fahrenheit for a specific, established time. The only way to achieve this temperature is by using a Pressure Canner. 

The Pressure Canner itself is a large kettle with a jar rack, a lid that locks in place, a safety valve, a vent, and gauge. Gauges indicate inside pressure and are either dial gauges, or metal weighted gauges. Individual cannes will come with instructions.  Read them throughly before using your canner.



The National Center for Home Preservation has extensive information on Pressure Canners as well as canning, drying, freezing, curing, smoking, pickling, fermenting and making jams and jellies. Ball Canning also offers a complete guide on canning, including some very helpful canning tutorials in the form of videos.

Whichever type of preserving  you are doing it is important to use ingredients at the peak of freshness. Follow the basic guidelines offered on either of the above websites, keep everything sterile, and your pantry will soon be filled with jars of delicious homemade preserves.

PRESSURE CANNING

Pressure canning is an economical method of preserving low acid foods and the only method recommended as safe by the United States Department of Agriculture (USDA) for low-acid foods such as vegetables, some fruits, meats, fish and seafood.  A temperature of 240 F must be reached and maintained for a specified amount of time to kill harmful bacteria. This temperature can be reached only by creating steam under pressure.


Pressure canners can be relatively expensive, but if properly cared for will last years. If you plant a good-sized garden or can get lots of produce cheaply, it is definitely worth having one in your pantry. If your family is small and canning is something you probably will not do that often, freezing and/or canning using a Hot-Water Bath is probably good enough.


Hot Water Baths, aka Boiling Water Baths, are suitable only for canning strong acid foods like tomatoes – and for finishing pickles, relishes, jams, jellies, chutneys, conserves, vinegary preserves and the like.


Pressure canners were redesigned in the 1970's. Models made before the 1970's were heavy-walled kettles with clamp-on or turn-on lids. Modern pressure canners are lightweight, thin-walled kettles.


To be considered a pressure canner for preserving food, and not just for cooking under pressure, the USDA recommends that the pressure canner be large enough to hold at least 4 quart-sized jars. Really, in this case, bigger is better.


A tight-fitting lid that holds the ‘controls’ covers the kettle itself. Clamps fasten down the lid. Basically, pressure canner controls are: a pressure gauge, often referred to as the ‘dial’; an open vent to let steam escape; and a safety valve that blows if the pressure becomes unsafe.


Like the hot-water bath canners, the pressure canner will have a removable rack to keep the jars from touching the bottom of the canner or each other, and/or a wire basket that lets you lift all your jars out at one time.


Food scientists have determined that 10 pounds in the sea-level zone (240 F/116 C) as the safest and most effective pressure to use for low-acid foods. Depending on your location across the country, that amount will be variable, make sure to read instructions for putting your food by carefully and adjust the pressure accordingly.


Do not be intimidated by pressure canning. Your new pressure canner, and I do recommend purchasing a new canner - not a used one, will come with instructions. Take the time to read them through carefully and you will realize that operation is not as difficult as you may think.