But pineapple slices or pieces are so hard they cannot be put directly into the jars as berries are. Pineapples must undergo a preliminary process to make them palatable and soft. This preliminary process is known in canning as "blanching."
After the pineapple has been prepared by paring and removing the eyes, it can be left in slices or cut into cubes. In cutting hold the pineapple at the top and use a sharp knife. It is then placed in a wire basket or a piece of cheesecloth for the blanching. Blanching means to immerse the product in boiling water for a certain length of time to reduce its bulk and soften it.
Pineapples are blanched for five minutes. We scald peaches and apricots, which are soft fruits; but we blanch pineapples, apples and quinces, the hard fruits.
Scalding means to immerse the product in boiling water for a very short time—just long enough to loosen the skins. Blanching is just a longer period of scalding.
When you blanch pineapples use only enough water to cover them. This same blanching water can be used for making the sirup. It contains much of the pineapple flavor and there is no reason for discarding it. But this is absolutely the only blanching water that is ever used. All other blanching water, particularly that in which vegetables are blanched, is full of objectionable acids that we want to get rid of, so under no circumstances must it be used. But with pineapples the object of blanching is primarily to soften the hard fiber, so there is no objection to using the blanching water.
After the pineapple has been in the covered kettle of boiling water for five minutes, it is held under cold water until cool enough to handle. Never let it soak in cold water, as that will impair its delicate flavor. After this it is packed into hot sterilized jars. Rubber rings are put on the jars, the covers are put in place—not tight—and the jars are put in the canner.
Pineapple is sterilized for thirty minutes in a hot-water-bath outfit; thirty minutes in a condensed steam outfit; twenty-five minutes in the water-seal; twenty-five minutes in the steam pressure under five pounds of steam, and eighteen minutes in the pressure cooker under ten pounds of pressure. At the end of the sterilizing period the jars are removed, the covers completely tightened and the joints carefully tested for leakage.
A thin or medium-thin sirup is best for pineapples. Measure the blanching water and to every two cups of it add three cups of sugar. If you wish the sirup thin heat until the sugar is dissolved. If medium-thin sirup is desired, boil it about four minutes or until it begins to be sirupy.
STEPS IN CANNING PINEAPPLE
1. Cut the pineapple into slices of desired thickness.