Canning

Pressure cooker is necessary in order to kill the botulism organisms that can survive unless food is heated from 240 to 250 degrees for specific time lengths. 240 is equivalent to 10 lbs of steam pressure.
Processing time at 10 lbs. of pressure (minutes):
Asparagus 25 pints 30 quarts
Carrots 25 pints 30 quarts
Corn 55 pints not recommended
Onions 25 pints 30 quarts
Potatoes 30 pints 40 quarts
Tomatoes 15 pints 20 quarts
Asparagus - 12 lbs yield 6 pint jars ‘stalk’ and 2 pint jars cut.
Beets - one bushel, by measure, cut in small thin slices yields 40 pint jars.
Cherries - 9 baskets yield 2 pint jars, pitted, or 7 pint jars whole.
Corn - 100 ears, yield an average of 14 pint jars.
Greens - 1 bushel, spinach, yields 10 pints jars. One bushel, dandelion, yields 13 pint jars.
Peaches - 2 and 1/4 lbs. yields 14 1 quart jars.
Peas - one bushel, pods well filled, yields 14 pint jars.
Pineapples - one-half crate, 15 pines, yields 30 pint jars.
Plums - one basket of 14 lbs. yields 25 pint jars.
Strawberries - one crate yields 26 pint jars canned or 31 glasses of jam - 7 1/2 ounce size.
String Beans - one bushel, by measure, yields 17 to 20 quart jars.
Tomatoes - 3 lbs. yield 1 quart jar.
Procedure:
In packing fruits for hot or cold pack canning, the product should be packed to within 1/2 inch of the top of the jar.
If using syrup on the product, fill jar with syrup to within 1 1/2 inches of top.
If using water or fruit juice, fill jar to within 1/2 inch of the top of the jar.
For open kettle canning, fill only one sterilized jar at a time with the boiling hot product and liquid to within 1/2 inch of the top of the jar and seal immediately.
1. Prepare puree and hot pack into sterilized jars.
2. Install rack and add 3 inches of water. Put on the cover, adjust or clamp. Let steam escape for 7-10 minutes.
3. Let pressure build up, adjust heat, and process for specific time.
4. Turn off heat and cool canner.
5. Remove jars from caner and adjust lids if necessary.
6. When the jars are completely cooled, check to see if the seal is complete.
7. Store in a cool, dark place.
When using heat the concentrated and add an equal amount of milk, heat to simmering point.
Canning fruit without sugar - all fruit and fruit juices can be successfully canned in jars without sugar, but the addition of syrup at the time of canning helps to develop and improve the flavor of the fruit. When canning fruit without sugar the jar is filled to within 1/2 inch of the top with water or fruit juice and the jar cooked method (hot or cold pack) is recommended.