The following vegetables are the only ones which must be blanched before canning:

Greens - All greens should be blanched about five minutes to reduce the bulk.

Corn - In order to prevent loss of the milk, corn should be blanched on the cob until it is firm to the touch and until the milk does not ooze out when the corn is pricked with a fork.

Beets, Carrots, Parsnips - Beets, carrots and parsnips should be blanched until the skins will slip off easily.

When Boiling Water is Used, place the fruit or the vegetables in a piece of cheese-cloth or in a crate; lower this entirely under the water, and heat for the required number of minutes. Blanch only a small quantity of the product at a time in order to keep the water as near the boiling point as possible all during the process.

For Blanching in Steam place the food in some perforated utensil or in a piece of cheese-cloth and suspend it in a tightly closed steamer. Greens should be blanched until no further shrinkage will occur. Blanching in steam generally requires a longer time than does blanching in boiling water. The steam must penetrate to all parts of the mass. For this reason do not crowd the fruits or vegetables, particularly when you are blanching greens.

The Cold Dip Which Follows Blanching rapidly chills the outside of the blanched fruit or vegetables and is accomplished by plunging them into cold water. "While the food should be cooled sufficiently to make it easy to handle, do not allow it to remain in the cold water too long.

Cooking or Processing in the Cold-Pack Method

Food to be canned by the cold-pack method is usually heated or, as it is called, processed in one of two ways.

1 - Continuous boiling in a hot-water bath (at 212° F.).

a - For a long period of time.

b - For a shorter period of time, if a small amount of lemon-juice or vinegar is used.

2 - Cooking at a high temperature in steam under pressure.

While a continuous period of cooking in boiling water may be successful for vegetables and meats, if the period is long enough, it is not generally considered as effective in destroying the organisms that cause spoilage as cooking in steam under pressure. As a precaution against botulinus poisoning, vegetables canned in the hot-water bath should be boiled after being opened, before they are used.

Acid as an Aid in Canning by the Cold-Pack Method

If a steam pressure cooker is not available, the use of a food acid (lemon-juice or vinegar) with foods processed in a hot-water bath increases the certainty of success in canning corn, peas, beans, asparagus and greens. The acid flavor is scarcely noticeable and to most persons not objectionable.

Quantity of Acid to Use - For each pint jar of vegetables, use one tablespoon of vinegar or lemon-juice and one teaspoon of salt. Boil the jars of vegetables in the hot-water bath for one and one-half hours, according to the directions given farther along in this chapter for each vegetable.