The convenience of this plan will be readily seen when it is understood that, with the exception of the special vegetables, the same method of preparation and the time given for the various steps in the canning process apply to all vegetables of the same class. Thus, if directions for a vegetable belonging to a certain class are not definitely stated in the text, it may be taken for granted that this vegetable may be canned in the manner given for another vegetable of the same class.
57. GENERAL DIRECTIONS.--The canning of vegetables may be most successfully done by the one-period cold-pack method. Tomatoes, however, because of the large quantity of acid they contain, may be canned and kept with little difficulty by the open-kettle method, but they will be found to keep their shape better if the cold-pack method is employed.
The time required for cooking any vegetable after it is packed in jars depends on the kind and the age. Therefore, if a vegetable is hard or likely to be tough, it may be necessary to increase the time given in the directions; whereas, if it is young and tender or very ripe, as in the case of tomatoes, the time for cooking may perhaps have to be decreased. Because, in altitudes higher than sea level, the boiling point of water is lower than 212 degrees Fahrenheit, the length of time for boiling foods in the water bath must be increased after an altitude of 500 feet is reached. Therefore, for every additional 500 feet over the first 500 feet, 10 per cent. should be added to the time given for the boiling in water. In case a pressure cooker is used, however, this is not necessary.
The canning directions here given are for 1-quart jars. If pint jars are to be used, decrease the salt proportionately; also, decrease the time for cooking in each case one-fifth of the time, or 20 per cent. If 2-quart jars are to be used, double the amount of salt and add to the length of time for cooking one-fifth, or 20 per cent. For instance, if a 1-quart jar of food requires 90 minutes, a pint jar of the same food would require 72 minutes and a 2-quart jar, 108 minutes.
GROUP 1--GREENS
58. In canning greens, or vegetables belonging to the first group, select those which are fresh and tender. Greens that are old and inclined to be strong and tough may require longer blanching and cooking. Look the greens over carefully, rejecting all leaves that are wilted or otherwise spoiled. Cut off the roots and drop the leaves into a pan of cold water. Wash these thoroughly a number of times, using fresh water each time, in order to remove all sand and dirt that may be clinging to them. Then proceed to blanch them for 10 to 15 minutes in steam, suspending the greens over boiling water in a piece of cheesecloth, a colander, or the top of a steamer. After blanching, dip them quickly into cold water. Then pack the greens tightly into jars and add 1 teaspoonful of salt to each jarful. No water has to be added to greens, because the leaves themselves contain sufficient water. When the jars are thus packed, adjust the covers and proceed to sterilize and cook the greens according to the directions previously given. If the water bath is to be used, boil them in it for 1-1/2 to 2 hours; but if the pressure cooker is to be employed for this purpose, cook them at a 5-pound pressure for 60 minutes or at a 10-pound pressure for 40 minutes.
GROUP 2--POD AND RELATED VEGETABLES
59. The best results in canning vegetables belonging to the second group will be derived when those which are fresh and tender are selected. As has been mentioned, the sooner vegetables are canned after they are taken from the garden, the better will be the canned product. Directions for practically all vegetables included in this group are here given.
60. ASPARAGUS.--Select tender asparagus, and proceed with the canning no later than 5 hours after it has been taken from the garden. Remove the hard portions at the ends of the stems, and cut the trimmed stems into pieces the length of the jars into which they are to be placed. If preferred, however, the asparagus may be cut into small pieces. Wash the cut asparagus thoroughly in cold water, and then sort out the uneven pieces that were cut off in making the stems even in length. These may be canned separately for soup. Lay the stems of asparagus in an orderly pile in a colander or a wire basket, cover it, and place it into a large vessel where it may be kept completely covered with boiling water for 5 minutes. Then cold-dip the asparagus quickly, and pack it neatly into the jars, keeping the tip ends up. Add 1 teaspoonful of salt to each jarful and pour boiling water into each jar until it is completely full. Adjust the covers and proceed to sterilize and cook the jars of food. Cook for 1-1/2 to 2 hours in the water bath, or, in the pressure cooker, cook for 60 minutes at a pressure of 5 pounds or for 40 minutes at a pressure of 10 pounds.
61. BRUSSELS SPROUTS, CABBAGE, AND CAULIFLOWER.--In canning Brussels sprouts, cabbage, or cauliflower, first prepare each vegetable as if it were to be cooked for the table. When thus made ready, blanch it with the aid of a square of cheesecloth or a colander in live steam, over boiling water, for 10 to 15 minutes. Then cold-dip it and pack it tightly into the jars. Add 1 teaspoonful of salt to each jarful and fill each jar with boiling water. Proceed next to sterilize and cook it according to the method selected. Boil for 90 minutes in the water bath; in the pressure cooker, cook for 60 minutes at a 5-pound pressure or for 40 minutes at a 10-pound pressure.