| Pint jars | 55 minutes |
| Quart jars | 90 minutes |
As soon as you remove jars from canner, complete seals if necessary.
In tin cans.—Pack hot sweetpotatoes to ¼ inch of top. Add ½ teaspoon salt to No. 2 cans; 1 teaspoon to No. 2½ cans. Fill to top with boiling water or medium sirup. Exhaust to 170° F. (about 10 minutes) and seal cans. Process in pressure canner at 10 pounds pressure (240° F.)—
| No. 2 cans | 70 minutes |
| No. 2½ cans | 90 minutes |
Questions and Answers
Q. Is it safe to process foods in the oven?
A. No, oven canning is dangerous. Jars may explode. The temperature of the food in jars during oven processing does not get high enough to insure destruction of spoilage bacteria in vegetables.
Q. Why is open-kettle canning not recommended for fruits and vegetables?
A. In open-kettle canning, food is cooked in an ordinary kettle, then packed into hot jars and sealed without processing. For vegetables, the temperatures obtained in open-kettle canning are not high enough to destroy all the spoilage organisms that may be in the food. Spoilage bacteria may get in when the food is transferred from kettle to jar.
Q. May a pressure canner be used for processing fruits and tomatoes?