Canning fresh corn is not for the faint of heart - and also not for the short of time.
Preserving corn requires serious pressure canning since corn is one of the lowest-acid vegetables. Whole-kernel corn may be canned in pint or quart jars. Because of its density and the long processing time needed, cream-style corn may only be packed in half-pint or pint jars.
a result of the long processing time and high pressure, you may find your home-canned corn to be fairly mushy. Sweeter varieties may turn brown when canned, so you might want to can a small amount and check the color and flavor before canning large amounts.
For best quality, preserve corn within six hours of harvest. The corn should be fully mature. Husk the ears, remove the silks, trim off the ends of the ears to remove small fibrous kernels, trim out any insect-damaged kernels, and wash the corn.
To prepare whole-kernel corn for canning, place the ears in 2 to 3 gallons of boiling water and blanch for 3 minutes after the water returns to a boil. Cool the ears in ice water for at least five minutes, drain, and cut the kernels from the cob at about three-fourths of their depth. Do not scrape the cob.
To prepare cream-style corn for canning, blanch the ears for 4 minutes in the boiling water. Cool the ears in ice water for at least five minutes, drain, and cut the kernels from cob at about one-half of their depth. Scrape the cob with the backside of a knife to remove the remainder of the corn pulp and combine with the half-kernels.
Now, for the actual canning, wash the jars and prepare the lids according to manufacturer's instructions. If desired, add 1 teaspoon salt per quart, 1/2 teaspoon per pint, or 1/4 teaspoon per half-pint jar.
For raw-packed whole-kernel style corn, fill the jars with the blanched corn, leaving 1 inch of head space. Add boiling water to the corn in each jar, keeping the 1 inch of head space. Wipe the rims of the jars with a clean, damp paper towel, add the lids, tighten the screw bands, and process.
For hot-packed corn, add 1 cup of hot water to each quart of whole-kernel or cream-style corn in a large pan, and bring it to a boil. Fill the jars with the hot corn and cooking liquid, leaving 1 inch of head space. Wipe the rims of the jars with a clean, damp paper towel, add the lids, tighten the screw bands, and process.
To process the corn in a pressure canner, place a jar rack, 2 inches of water, and the sealed jars in the canner. Fasten the lids, and heat the canner on high heat. After exhausting steam for 10 minutes, pressurize the canner. Start timing once the desired pressure has been reached. Regulate the heat to maintain the desired pressure.
For raw-pack or hot-pack whole-kernel corn, process pints for 55 minutes or quarts for 85 minutes at 11 pounds of pressure if you have a dial-gauge canner or 10 pounds of pressure if you have a weighted-gauge canner. If you live above an elevation above 1,000 feet, process at 15 pounds of pressure.
For hot-pack cream-style corn, process pints or half-pints for 85 minutes at 11 pounds of pressure if you have a dial-gauge canner or 10 pounds of pressure if you have a weighted-gauge canner. If you live above an elevation above 1,000 feet, process at 15 pounds of pressure.
When the endless processing is complete, remove the canner from heat. Air-cool the canner until it is fully depressurized, then slowly remove the weighted gauge or open the petcock. Carefully unfasten and remove the canner lid. Remove the jars from the canner with a jar lifter and place them on a towel or rack. Do not retighten the screw bands. Air-cool the jars for 12 to 24 hours. Remove the screw bands and check the lid seals. If the center of the lid is indented, wash, dry, label, and store the jar in a clean, cool, dark place. If lid is not sealed, examine and replace the jar if it is defective; use a new lid, and reprocess as before. Wash the bands and store separately.
Canned sweet corn is best if consumed within a year and safe as long as lids remain vacuum sealed.