I emailed Presto (I have 2 of their 6 qt cookers) - got an email and a tel call.
You can use pressure cookers for canning - two points - do not use over 3000 ft altitude - and use the instructions for canning in pressure COOKERS specifically. They emailed them - I've attached them
CANNING IN THE 4 & 6 QUART PRESSURE COOKERS
Pressure canning is recommended by the United States Department of Agriculture, Washington, D.C., as the only safe method for canning low-acid foods - vegetables, meat, poultry, and fish. These
instructions for canning at 15 pounds pressure are according to research done by the Department of Food Science and Nutrition, Agriculture Experiment Station, University of Minnesota, St. Paul,
National Presto Industries, Inc.
3925 North Hastings Way
Eau Claire, WI 54703-3703
1-800-368-2194 Home Economist
1-800-877-0441 Parts and Service
Why Pressure Canning?
Water boils at 212 degrees F. (except in mountainous regions) and this is sufficient to arrest or destroy some spoilage organisms - enzymes, molds, and yeast. However, a temperature of 240 degrees F. or above is needed to destroy harmful bacteria, especially clostridium botulinum. In pressure canning, some of the water in the Pressure cooker is converted to steam and, after all air is exhausted through the vent pipe and air vent/cover lock in the cover, the pressure regulator is placed on the vent pipe. Expanding steam will close the air vent/cover lock and will then create pressure. As pressure within the pressure cooker increases, temperature increases to 15 pounds pressure -- 250(F.
Four specific agents produce food spoilage. They are enzymes, molds, yeast and bacteria. Three of them (enzymes, molds and yeasts) are easily destroyed by heat during the processing. Bacteria, especially clostridium botulinum, can be destroyed only with temperatures above boiling. And their destruction is of prime importance. If enzymes are not destroyed, the quality of food is lowered. Unchecked mold may spread through the entire contents of a container of food. Yeast causes fermentation. Bacteria spoilage fall into four groups:
1) Fermentation, recognized by the formation of gas and acid, which causes
food to sour
2) Flat Sour, in which acid is produced, but no gas is formed
3) Putrefaction, characterized by gas, bad odor and sometimes by darkening of food
4) Toxins or poisonous substances which may show no visible signs of spoilage unless other spoilage organisms are also present
As a safeguard against using canned foods that may be affected with spoilage that is not readily detected, heat all low-acid foods (all meats and all vegetables) to 15 pounds pressure before tasting or using.
Pour canned food into a pressure cooker. Close cover securely. Place pressure regulator on vent pipe. When pressure attains 15 pounds, remove pressure cooker from heat. Let pressure drop of its own accord. Another method to detect food spoilage is to pour canned food into a saucepan and boil 10 - 15 minutes before tasting or using.
Many times odors that cannot be detected in the cold product will become evident by these methods. If after pressure cooking or boiling, food does not smell or look right, discard it without tasting.
Foods, such as fruits and tomatoes, may also be canned in a pressure cooker.
Young, tender, fresh vegetables, slightly immature, are better for canning than overripe produce. As a rule, vegetables are best if canned immediately after picking, since flavor decreases upon standing and
often unpleasant color changes take place. Avoid bruising vegetables because spoilage organisms grow more rapidly on bruised vegetables than on unblemished ones.
Wash and prepare garden fresh vegetables as you would for cooking. Vegetables may be raw packed or precooked before they are processed. If raw, pack prepared vegetables into clean jars.
To precook vegetables, cover with boiling water and cook until heated through. Pack precooked vegetables into clean jars. Leave one inch head space in jars.
Can with or without salt. If salt is desired use only pure canning salt. Table salt contains a filler which may cause cloudiness in bottom of jars. Add 1/2 teaspoon canning salt to each pint jar (1/4 teaspoon salt to each one-half pint) if desired. Cover vegetables with boiling water leaving one inch head space.
When vegetables are precooked, some of the nutrients dissolve in the water. So whenever possible, the precooking water should be used as liquid to cover the vegetables. However, do not use the precooking water for canning turnips, greens, kale and sometimes asparagus, because the precooking water may be bitter.
Adjust cap closure according to manufacturer's instructions. Follow the specific directions for the operations of your cooker. Place boiling water, cooking rack and jars in the cooker. Close cover securely. Do not place the pressure regulator on the vent pipe. Exhaust air from the cooker and jars by adjusting heat to a relatively high setting to obtain a free flow of steam from the vent pipe. Allow steam to flow for 5 minutes. Place the pressure regulator on the vent pipe. Continue heating
until 15 pounds pressure is reached.
Process vegetables according to chart.
Canning Meat and Poultry
Cut meat or poultry into pieces convenient for canning. Precook meat until red color changes to light brown. Precook poultry until medium done. Precooking can be done by boiling, frying, or roasting.
To precook by boiling, make a concentrated broth from bones and meat or poultry trimmings. Heat to boiling and precook meat or poultry in broth. Meat should not be browned with flour, nor should flour be used in the gravy of meat used for canning.
Pack hot meat or poultry into clean jars leaving one inch head space. Do not pack tightly. Salt may be added, 1/2 teaspoon for each pint, or it may be added at serving time. Cover with hot liquid broth, meat juice or water. It is important to leave one inch head space.
Adjust cap closure according to manufacturer's instructions. Follow the specific directions for the operations of your cooker. Place boiling water, cooking rack and jars in the cooker. Close cover securely. Do not place the pressure regulator on the vent pipe. Exhaust air from the cooker and jars by adjusting heat to a relatively high setting to obtain a free flow of steam from the vent pipe. Allow steam to flow for 5 minutes. Place the pressure regulator on the vent pipe. Continue heating until 15 pounds pressure is reached.
Process meat and poultry according to chart.
Canning Fish and Seafood
Only fresh fish should be canned and these should be bled and thoroughly cleaned of all viscera and membranes when caught, or as soon as possible. Canning should be restricted to proven varieties where it is definitely known that a product of good quality may be obtained.
Clams, Whole (Littleneck)
Scrub clams and soak overnight in 10% brine. Open clams and wash in salted water using 1 tablespoon salt for each quart of water. Cover clam meat with boiling water, to which 1/8 teaspoon citric acid crystals have been added to each quart of water. Allow to stand 1 minute. Pack loosely into clean, hot Mason jars, leaving 1 inch head space. Cover with hot concentrated clam juice to 1/4 inch from top. Adjust jar lids. Process according to chart.
Place crabs in ice water 1 - 2 minutes. Separate claws from body, remove waste portions, and wash thoroughly. Place bodies and claws with 2 cups water in cooker, and cook 5 minutes at 15 pounds pressure. Cool cooker at once. Remove meat from shells. Wash thoroughly in salted water using 1/2 cup salt to 2 quarts water. Drain and dip in solution of 1/2 cup vinegar to 2 quarts water. Drain and remove all excess moisture. Pack loosely into clean, hot Mason jars, leaving 1 inch head space. Add 1/2 teaspoon salt and cover with boiling water. Adjust jar lids. Process according to chart.
Fish - General Method
Cod, Mackerel, Herring, Lake Trout, Whitefish, and Mullet. Clean fish thoroughly, fillet large fish or leave small pan fish whole. Cut into container length pieces and soak in brine, 1 cup salt to 1 gallon
water, for 1 hour. Drain. Pack with skin side of fish to the outside of the Mason jar. Leave 1/2 inch head space. Then submerge open jar in a kettle containing hot brine, 1/2 cup salt to 1 gallon of water, and boil 20 minutes. Remove, invert and drain thoroughly. Add a bay leaf and a slice of onion to each jar, if desired. Adjust jar lids. Process according to chart.
Plunge live lobsters in boiling, salted water, 2 tablespoons salt to 1 gallon water. Cook 15 - 30 minutes depending on size. Remove and dip in cold lightly salted water. Remove meat and wash quickly. Drain. Dip meat in solution of 1/2 cup vinegar to 2 quarts water. Drain and remove all excess moisture. Pack in clean, hot Mason jars, leaving 1/2 inch head space. Cover with hot brine, 1 1/2 tablespoon salt to 2 quarts water. Adjust jar lids. Process according to chart.
Clean and wash fish thoroughly. Cut into container length pieces, leaving in backbone. Soak in brine, 1/2 lb. salt to 1 gallon water, for 1 hour. Drain well. Pack solidly in Mason jars leaving 1/2 inch head space. Adjust jar lids. Process according to chart.
Shrimp should be canned when absolutely fresh as they deteriorate quickly. Wash shrimp thoroughly, peel and wash again. Cover with cold brine, 1/2 cup salt to 1 quart water, for 20 - 30 minutes depending on size. Drain. Place on cooking rack and cook 6 to 8 minutes in boiling brine, proportions as above. Dry and cool shrimp. Pack loosely in clean, hot Mason jars leaving 1 inch head space. Fill containers with boiling brine, 1 1/2 tablespoon salt to 1 quart water, leaving 1 inch head space. Adjust
jar lids. Process according to chart.
Canning Fruits and Tomatoes
Fruits and tomatoes may be canned in a pressure cooker. The pressure processing method for fruits and tomatoes gives a heat treatment equivalent to the much longer processing in boiling water bath canner.
Select firm, fully-ripened but not soft fruit or tomatoes. Do not can overripe tomatoes. Wash, peel, core, or remove pits, if necessary. To loosen skins of peaches, apricots and tomatoes, blanch for 30 seconds in boiling water. Dip into cold water and peel. Cherries and plums are usually canned whole. Prick the skins with a fork to prevent them from breaking during processing. Leave fruit whole or cut as desired (halves, slices, or chunks).
Some fruits tend to darken while they are being prepared. To prevent the darkening, place fruit in an ascorbic acid solution (1 teaspoon ascorbic acid to 1 gallon water) or use ascorbic acid or citric acid mixtures according to manufacturer's instructions.
Although fruit has better color, shape and flavor when it is canned with sugar, it may be canned unsweetened if desired. Sugar is used for flavor. It is not used in high enough concentration to act as a preservative.
White sugar is preferable to brown sugar for canning. Honey or light corn syrup may be used to replace up to 1/2 the sugar. If you wish to use sugar substitutes, follow manufacturer's instruction.
The amount of sugar desirable to use in preparing syrups will depend upon the tartness of the fruit and on your preference. It should be remembered that fruit, when heated, releases some of its juices which will dilute the syrup in proportion to the juiciness of the fruit.
Syrups for Canning Fruits
Very Light 1/2 cup sugar to 1 qt. Water yields 4 cups
Light 1 cup sugar to 1 qt. Water yields 4 1/2 cups
Medium 2 cups sugar to 1 qt. Water yields 5 cups
Heavy 3 cups sugar to 1 qt. Water yields 5 1/2 cups
Heat sugar with water or juice until sugar is dissolved. Add fruit and cook until heated through. Pack fruit into clean jars to within 1/2 inch of top of jar. Cover with hot liquid leaving 1/2 inch head space.
The liquid may be syrup, fruit juice or plain water.
If preferred, fruit may be packed raw (except apples, cranberries, figs and strawberries) into containers and covered with boiling hot syrup. When this is done, processing time need not be increased. When fruit is packed cold, it shrinks during processing, and the container is less full than when fruit is preheated in boiling syrup before packing. Pack tomatoes into clean jars to within 1/2 inch of top of jar, press down to release juice and fill spaces. Add 1 tablespoon of lemon juice per pint. Add 1/2 teaspoon canning salt to each pint jar if desired.
Adjust cap closure according to manufacturer's instructions. Follow the specific directions for the operations of your cooker. Place boiling water, cooking-canning rack and jars in the cooker. Close cover securely. Do not place the pressure regulator on the vent pipe. Exhaust air from the cooker and jars by adjusting heat to a relatively high setting to obtain a free flow of steam from the vent pipe. Allow steam to flow for 5 minutes. Place the pressure regulator on the vent pipe. Continue heating until 15 pounds pressure is reached. Process fruits and tomatoes according to chart.
After Processing Time Is Complete
At the end of processing time, turn the burner to "Off" or remove cooker from the heat source. Let the pressure drop of its down accord, do not quick cool. When pressure is completely reduced, remove the pressure regulator from the vent pipe. Allow cooker to stand approximately 10 minutes, then remove cover and jars.
Processing Time Chart For Use with 4 or 6 Quart Pressure Cookers
Processing times at 15 pounds pressure apply only to altitudes up to 3,000 feet. Do not use a 4 or 6 quart pressure cooker at altitudes above 3,000 feet. Processing times are for 1/2 pint and pint jars.
Use 5 cups water in pressure cooker for processing. Exhaust air from the cooker and jars by adjusting heat to a relatively high setting to obtain a free flow of steam from the vent pipe. Allow steam to flow for 5 min.
Beets, whole or sliced/25
Corn, whole kernel/60
Greens, all kinds/45
Okra and Tomatoes/25
Poultry, with bone/40
Game fowl, with bone/40
Lobster *use only 1/2 pint Mason jars/45