Care and Maintenance of a Pressure Cooker

The outside surface may be kept bright and shiny by cleaning with a good silver polish or simply by washing with soap and water. Iron and various materials in water and foods may darken the inside of the cooker but this discoloration will in no way affect the food cooked. These stains may be removed by using a solution of water and cream of tartar. For each quart of water, use one tablespoon of cream of tartar. Pour enough solution into the cooker to cover the discoloration (do not fill over 2/3 full), then close the cover securely. Place regulator on the vent pipe and heat until 15 pounds of pressure is reached. Remove the cooker from the heat; allow cooker to stand for two or three hours. Remove the regulator, open cooker and empty it's contents. Scour thoroughly with a soap impregnated steel wool cleaning pad; wash, rinse and dry. Due to the acidic nature of the water supply in some areas, deterioration of the interior surface of the cooker may occur. To minimize this effect, thoroughly scour the inside of the cooker with an abrasive cleaner at least once a year. Each time the cooker is washed, remove the sealing ring and wash in warm, sudsy water; rinse, dry and replace in cover.

The air vent/cover lock may be removed for occasional cleaning or for replacing. Wash all parts in warm, sudsy water. Use a soft cloth or small nylon brush to clean the cover hole. The small gasket must be in place when reassembling the air vent/cover lock.

The over-pressure plug can be removed for cleaning by pushing it out of it's opening from the top of the cover. After cleaning, reinsert the plug by pushing the dome side of the plug into the opening from the under-side of the cover until the bottom edge is fully and evenly seated against the under-side of the cover. When the over-pressure plug is properly installed, the word, "top," will be visible on the over-pressure plug when viewing the outside of the cover.

If the over-pressure plug is ever forced out of it's cover opening due to excess pressure while cooking or canning. Do not attempt to use the released over-pressure plug! Pouring water into a dry, over-heated cooker may crack the metal. Do not strike the rim of the cooker body with any cooking utensils as this will cause damage to the rim and allow steam to escape. When your pressure cooker is not in use, invert the cover on the cooker body and store in a dry place. Storing the cooker with the cover locked may cause unpleasant odors and deform the sealing ring.

To ensure safe operation and satisfactory performance, replace the over-pressure plug every time you replace the sealing ring or earlier if it becomes hard, deformed, cracked, worn or pitted. Replace the sealing ring and over-pressure plug at least every three years. Failure to follow these instructions could result in bodily injury or property damage. If the cooker body or cover handles become loose, tighten with a screwdriver. If leakage of moisture or steam develops while using your cooker, check the following possible causes:

• The formation of a small amount of moisture under the pressure regulator is normal when canning or cooking first begins. This condensation is a result of the temperature of the pressure regulator being lower than the rest of the cooker. If excess condensation continues, the vent pipe may be loose and should be tightened with an adjustable wrench.
• Leakage between the cover and body is usually caused by shrinkage of the sealing ring after prolonged use. Replace the sealing ring and over-pressure plug. 
• A slight amount of leakage around the air vent/cover lock is normal when canning or cooking first begins. If leakage continues, the cover handles may not be fully aligned with the body handles, therefore, the cover lock can not engage. Clean the air vent/cover lock occasionally to ensure that it operates correctly. Replace the small gasket if cracked or nicked. 
• A small amount of steam or moisture may be visible around the over-pressure plug when canning or cooking occurs. This will stop when the over-pressure plug seals. If leakage continues, clean or replace over-pressure plug. 

Do not operate the pressure cooker with continual leakage. If the preceding steps do not correct the problem, replace the entire cooker. If the pressure cooker becomes difficult to open or close, replace the sealing ring.

Important: The sealing ring, over-pressure plug and rubber gasket of the vent/cover lock may shrink, become hard, deformed, cracked, worn or pitted with normal use. Exposure to high heat, such as, a warm burner or oven top will cause the parts to deteriorate rapidly. When this happens, replace the sealing ring, over-pressure plug and the small rubber gasket of the air vent/cover lock. Replace the sealing ring and over-pressure plug at least every three years. Before inserting a new sealing ring, clean the sealing ring groove with a nylon brush.

Pressure Canning

The United States Department of Agriculture recommends the pressure cooker as being the only safe method for canning low acid foods; vegetables, meat and poultry.

There are invisible micro-organisms present all around us. Fruits, vegetables and meat contain these micro-organisms naturally and yet they are not a problem unless food is left to sit for extended periods of time, causing   food spoilage. This is nature's way of telling us when food is no longer fit to eat.

There are four basics agents of food spoilage; enzymes, mold, yeast and bacteria. Canning disrupts the natural spoiling process so the food can be preserved safely. Molds, yeast and enzymes are destroyed at temperatures below 212 degrees Fahrenheit; the temperature at which water boils (except in mountainous regions). Therefore the boiling water process is sufficient to destroy those agents. 

Bacteria however, are not as easily destroyed. The bacteria, clostridium botulinium, produces a spore that makes a poisonous toxin which causes botulism. The spore is not destroyed at 212 degrees Fahrenheit. In addition, the bacteria thrives on low acid foods in the absent of air. For a safe food product, low acid foods need to be processed at 240 degrees, which can be achieved only with a pressure cooker. 

In pressure canning, some of the water in the pressure cooker is converted to steam, which creates pressure within the cooker. As pressure increases, temperatures increases; 5 pound increments at 228 degrees Fahrenheit, 10 pounds pressure at 240 degrees Fahrenheit and 15 pounds of pressure at 250 degrees Fahrenheit. This pressurized heat destroys the potentially harmful spores. As the jars cool, a vacuum is formed, sealing the food within and preventing any new micro-organisms from entering and spoiling the food.

As a safeguard against using canned foods, which may be affected with spoilage that is not readily detected, boil all low acid foods and tomatoes for ten minutes at altitudes below a thousand feet. Extend the boiling time 1 minute for each thousand-foot increase in altitude.

Many times odors that cannot be detected in the cold will become evident by this method. If after boiling, food does not smell or look right, discard it without tasting! 

Mason Jars: While there are many styles and shapes of glass jars on the market, only mason jars are recommended for home canning. Mason jars are available in half pints, pints and quarts; with threads on the cap which may be screwed on. See the owners manual of your pressure cooker for the correct size of mason jars to be used. 

Closure of Mason Jars: The two-piece vacuum cap consist of a flat metal lid held in place by a screw band. A rubber compound on the underside of the lid forms a seal during the process. Follow the closure process of the manufacturer to be certain there is a good seal. If the closure has not sealed, completely reprocess or use the food immediately. Refer to the closure directions for additional information.

Maximum Jar Capacity: An example of a 16 quart pressure cooker and it's equivalent jar capacity.

•  12 half-pint jars
• 10 pint jars
• 7 quart jars