Blanching and Cold-Dipping
The most important steps in canning are the preliminary steps of blanching, cold-dipping, packing in hot, clean containers, adding hot water at once, then immediately half sealing jars and putting into the sterilizer. Spoilage of products is nearly always due to carelessness in one of these steps. Blanching is necessary with all vegetables and many fruits. It insures thorough cleansing and removes objectionable odors and flavors and excess acids. It reduces the bulk of greens and causes shrinkage of fruits, increasing the quantity which may be packed in a container, which saves storage space.
Blanching consists of plunging the vegetables or fruits into boiling water for a short time. For doing this place them in a wire basket or piece of cheesecloth. The blanching time varies from one to fifteen minutes, as shown in the time-table.
Spinach and other greens should not be blanched in hot water. They must be blanched in steam. To do this place them in a colander and set this into a vessel which has a tightly fitting cover. In this vessel there should be an inch or two of water, but the water must not be allowed to touch the greens. Another method is to suspend the greens in the closed vessel above an inch or two of water. This may be done in a wire basket or in cheesecloth. Allow the water to boil in the closed vessel from fifteen to twenty minutes.
When the blanching is complete remove the vegetables or fruits from the boiling water or steam and plunge them once or twice into cold water. Do not allow them to stand in the cold water. This latter process is the Cold Dip. It hardens the pulp and sets the coloring matter in the product.