Corn is a low-acid food and must be processed using a pressure canner. Boiling water processing will give a good seal, but cannot give adequate heat treatment for low acid foods so the corn would end up sealed in a jar with live bacteria that, during storage, could make toxin that would cause a severe illness if consumed. To ensure adequate processing, follow current tested recipes and use equipment in good working order. If your pressure canner has a dial gauge, have it calibrated at the beginning of each canning season. Make sure you use an accurate timer when canning; one study found 20% of timers used in homes were inaccurate.
The super sweet cultivars of corn contain enough sugar to turn the corn brown during processing and storage; this is a quality change but the flavor is affected. In some regions, commercially canned corn can be purchased more economically than you can home can it; check prices in your area. The following is a recipe based on current USDA recommendations for raw pack corn; check the USDA reference on the main menu for a hot packed corn recipes and cream style corn recipes. The canned creamed corn has extremely long processing times because it is a thick product and it takes extra time for the center of the jar to be adequately heated.
Corn freezes beautifully. If you have the freezer space, frozen corn is an excellent vegetable to store frozen. There are natural enzymes in corn that need to be inactivated before frozen storage to protect quality. These enzymes are inactivated by a hot blanch treatment.
To blanch corn, bring 6 to 8 qts of water to a boil and submerge several ears at a time. Blanch the ears 5 to 6 minutes. Remove the corn ears and immediately put in cold water to stop the heat treatment.
Cut the corn from the cob. For whole kernel, cut the corn close to the cob. Pack corn into freezer bags or containers, leaving 1/2 inch headspace for expansion (water expands when frozen and foods are mostly water). Store at 0 F. For best quality, consume within one year.
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FREEZING CORN ON THE COB
Each year recipes circulate for storing corn in the freezer while still on the cob. Frozen foods are as safe coming out of the freezer as they were going in as long as they have been held below freezing temperatures. However, it is extremely difficult for householders to achieve good quality corn on the cob. Corn contains enzymes that degrade flavor and odor during frozen storage unless these enzymes are inactivated by heat. Before freezing whole kernel corn, the ear is blanched to give a heat treatment to the enzymes in the kernel. Since the cob was being discarded in that recipe (above) it didn't matter if the enzymes in the cob were given adequate heat treatment or not. However, if you are storing the cob too, a longer heat treatment is needed for quality. Unfortunately, this longer heat treatment over cooks the corn kernel. The USDA and the Ball Corp. publish recipes for freezing corn on the cob with blanch times of 8 to 10 minutes. These recipes are safe, but many consumers complain about the quality after so much heat and these recipes also require a lot of freezer space for storing a small amount of edible product.
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