Home canning of foods high in acidity is not difficult, but it requires proper equipment and careful attention to directions. The following information has been compiled using the "Ball Blue Book--The Guide to Home Canning and Freezing" and publications on canning from the U.S. Department of Agriculture.
Through the process of canning, heat destroys potentially harmful microorganisms and enzymes. At the same time, a partial vacuum is formed and the jar seals, preventing recontamination of the food inside.
Foods that contain natural acid, such as fruits, can be safely processed using a water bath canner. This is a large kettle with a rack that fits inside to hold the canning jars separated and off the bottom so heat can penetrate properly. Standard glass canning jars with two-piece vacuum lids should be used.
Select Perfect Fruit
It's important to select firm, ripe, unblemished produce for canning. Only enough food for one canner load at a time should be prepared. Although instructions vary for different fruits, the following information on canning peaches is representative.
Begin by assembling the canner and jars already mentioned, along with a long-handled spoon, sharp knife, non-metallic spatula and clean potholders, dishcloths and towels. A jar lifter--a tong-like device with heat resistant handles and soft plastic tips to protect the jars--is another good item to have on hand.
Check that the canning jars are free of chips, cracks or defects, then wash the jars and closures in hot soapy water. Rinse well and leave in hot water until needed. (A dishwasher may also be used to wash the jars and keep them warm.)
How to Make Syrup
Make a light or medium syrup using one of the following formulas. Water or fruit juice may be used for the liquid.
Light--2 cups sugar plus 1 quart liquid (yields five cups syrup).
Medium--3 cups sugar plus 1 quart liquid (yields 5 1/2 cups syrup).
Medium with Corn Syrup--1 1/2 cups sugar, 1 cup corn syrup and 3 cups liquid.
Medium with Honey--1 cup sugar, 1 cup honey and 4 cups liquid.
Place the sugar (and corn syrup or honey) and liquid in a saucepan and heat until the sugar dissolves. The syrup should be kept hot until needed, but don't allow it boil down.
Also place 2 tablespoons salt and 2 tablespoons vinegar in a large bowl. Add 1 gallon of water and set aside.
Wash and rinse the peaches, then, using a slotted spoon or wire basket, lower them into a pot of boiling water for about one minute to loosen the skins. Remove the peaches, dip in cold water and peel.
Cut the peaches in half and remove the pits. Scrape the cavities to remove the pink or red fibers, which are likely to turn brownish after canning.
Drop the halves into the bowl of prepared water to prevent the fruit from darkening. Do not leave them in the solution for more than 20 minutes, however, and rinse thoroughly before packing.
Pack the peaches into the prepared canning jars, cavity side down, layers overlapping (Step 1). Cover the peaches with hot syrup, leaving 1/2 half inch head space. It will take 1/2 to 3/4 of a cup of syrup for each pint jar; one to 1 1/2 cups for each quart jar.
Run a non-metallic kitchen utensil gently between the fruit and jar (Step 2) to release air bubbles. Add more syrup if needed.
Wipe the rim and threads of the jar with a clean, damp cloth, then place the vacuum lid so the sealing compound is next to the jar. Add the band, screwing it down evenly and tightly.
The Water Bath
As each jar is filled, stand it in the rack of a boiling water bath canner. The water in the canner should be hot but not boiling. When the rack is filled, the water needs to cover the jars by one or two inches. If it doesn't, add more hot water (Step 3).
Cover the canner and bring the water to a boil. Adjust the heat to maintain a steady boil. Start counting the processing time when the water reaches a full boil. Process pints 25 minutes, quarts 30 minutes. If the water boils away during the processing time and exposes the tops of the jars, add more boiling water to maintain the proper level.
When the processing time is completed, remove the jars (Step 4) from the canner and stand on a clean cloth or towel, out of drafts and with space between for air to circulate. Do not retighten the jar bands.
After 12 to 24 hours, check the seals by trying to push down on the lid center. If it depresses but springs back, the jar is not sealed.
If the lid is not already concave but holds when pushed down, the seal is questionable. Remove the screw band and carefully lift the jar by the edges of the lid just a fraction of an inch above a padded surface. If the lid comes off, the contents should be reprocessed using a new metal disc with sealing compound.
Before storing, remove the metal bands from the sealed jars, be certain the jars are clean and labeled with the contents and date. If stored in a dry, dark, cool place, canned peaches should remain in optimum condition for a year.
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