Canning & Preserving: Methods & Basic Terms

There are two traditional methods to can; Pressure or Stream Canning and Water-Bath Canning.  Here are simple explanations to both and what types of foods you could use for each type.

Pressure Canning

Steam or Pressure canning is the method of processing your foods under pressure at a temperature of 240 degrees.  In pressure canning you will hear the term pounds of pressure.  Most pressure canners come with weighted gauges that measure either at 5, 10 or 15 pounds of pressure, it will vary depending on what type of food you are processing.

A pressure canner is the only kitchen utensil that supplies enough heat to destroy the spores of bacteria that cause botulism.  It is used to process low acid vegetables: beans, green beans, corn, eggplant, mixed vegetables, blackeye peas, okra, pumpkin and meats.

Water-Bath Canning

WaterBathcanning is simple processing your food at the temperature of 212 degrees.  This is simply using a large stock-pot type kettle to process your jars in boiling water.

This method can only be used in foods that are highly acidic such as fruits, tomatoes, pickles, applesauce, jams and jellies and even some juices.  Enough heat is supplied by boiling water to destroy the bacteria, enzymes and molds only in highly acidic foods.

Home Canning Terms

In canning there are many terms used that if you are new to canning you may not be familiar with.  Here are some of the basic terms and what they mean:

Jar Lid-The shallow piece of metal used to cover the opening of the jar.

Metal Band-This is the band that is threaded that holds down the jar lid and makes your two-piece metal cap.

Jar Rubber-This is the flat ring that is used as a gasket in the reusable Tattler Lids.

Acid Foods-These are foods that naturally contain .36 to 2.35% acid or foods that are preserved in vinegar.

Low Acid Foods-These are foods that contain little to no natural acid.

Processing-This is the term used to refer to cooking of your jars of food in either a water-bath canner or pressure canner for a long enough time to destroy bacteria, enzymes, molds and yeasts.

Cold-Pack or Raw Pack-This is a method used when jars are filled with raw food, then jars are filled with liquids and processed.

Hot Pack-this is the method used when you are filling your jars with hot food, then they are processed to the recipe specifications.

Head Space-This is the amount of space left at the top of the jar when you are filling or packing your jar with food.

Partial Seal-This is to refer to leaving the metal band on loosely while the jars are being processed.  The jars are then closed airtight as soon as they are removed from the canner to create a vacuum seal.

Vacuum Seal-When the proper caning procedures are followed, within 6-12 hours after being removed from the canner, as the jar cools everything in it shrinks and a partial vacuum forms.  If the jars have sealed properly, the center of your conventional canning lid should have a slight indentation and not pop back when you apply pressure.  If it makes a popping noise, it did not seal properly and needs to be refrigerated or re-processed.  When you have a proper vacuum seal it will prevent air from going back into your sealed jars and keep your foods preserved.

While this is not an all-inclusinve list, it will provide you with the basic terms that are used in canning.  If something comes up along the way that you would like to be further explained, please feel free to comment and I will do my best to explain it as we go along.

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