Preserving those golden fields of corn

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corn-on-the-cob-501903_640September is the beginning of harvest season, which means that sweet corn will soon start to show up at roadside stands, farmers’ markets and grocery store shelves.

Getting it

If you grow your own corn, harvest it when the silks become dry and brown and the kernels are milky when cut with a thumbnail. When buying corn remember that fresher is sweeter.

Purchasing corn at a roadside stand or farmers market with a cornfield out back is the best bet for fresher, sweeter corn. Ears should be bright green, firm and plump. Without pulling back the husk, feel the ear down to the silks area. The silks should be dried-looking but not shriveled. Husks should be left in place until you’re ready to cook the ear. If the husk is peeled back a few inches for a visual inspection, the ear begins to dry out, so avoid purchasing ears with peeled husks. If you’re going to buy a large quantity for a big gathering or for storage, ask if you can sample an ear. Corn should be sweet and tasty when eaten raw.

Once you’ve shucked the ear, the freshest corn will have shiny kernels. Organically grown corn may have a worm or two; pick them off and don’t let this bother you.

Sweet corn to be eaten the same day need not be refrigerated, but keep it in a cool spot out of strong light.

Storing fresh  

If you want fresh corn to keep, you must handle it carefully. Store corn in a cold moist place and be aware that fresh corn won’t keep much past five days. The optimal storage conditions are near 32°F and 95% relative humidity, which can be difficult to achieve in the average house. Expect shortened shelf-lives as storage conditions deviate from the ideal, with as much as 25% less time for every 10°F increase in temperature.

Refrigerate corn in the husk if you plan to eat it more than 24 hours after purchase. Wrap ears in a moist paper towel and then place them in a plastic bag and seal it. Try to eat fresh corn as soon as possible because each day it’s stored, it loses some sweetness. Although some varieties retain adequate sweetness for up to ten days, it’s best to enjoy corn within five days of purchase or harvest. Avoid leaving sweet corn in your car on a hot day or take along a cooler with ice cubes in locking plastic bags to keep it cool.

Drying                                                                                                                                

To dry corn, husk, remove silks and trim ends. Blanch whole ears of corn by dipping them in boiling water until the yellow of the kernels brightens, about three minutes. Blanching is necessary to inactivate enzymes in order to retain flavor during drying and discourage spoiling and discoloration. Cut kernels from the cob after blanching. Dry the corn in a food dehydrator or on cookie sheets covered with window screens or a light cloth.

Canning

There are two ways to can whole kernel sweet corn, hot packing and raw packing. Both involve using a pressure canner because boiling water canning does not provide enough heat to kill off potentially toxic bacteria that can grow in canned corn and other low-acid foods. Select ears ranging from not quite ripe to perfect for eating fresh. Some types of corn, especially sweeter varieties and young ears, may turn brown during canning, so it’s best to can a small amount and check color and flavor before canning large amounts. A bushel of corn yields six to eleven quarts of canned corn.

Preparation for canning                                                                                                  

To prepare corn for canning, first blanch the ears, then cut the corn off the cob at about three-fourths the depth of the kernel. Do not scrape the corn. Processing times are the same for either hot or raw packing: When using a dial-gauge pressure canner, process pints for 55 minutes at 11 pounds per square inch (PSI) and quarts for 85 minutes at 11 PSI, and when using a weighted-gauge pressure canner, process pints for 55 minutes at 15 PSI and quarts for 85 minutes at 15 PSI.

 

Hot pack method

To hot pack, mix one cup of hot water per each quart of corn. Heat to boiling and simmer five minutes in a saucepan. Add one tsp of salt per quart. Fill canning jars with corn and cooking liquid, leaving one inch of headspace. Adjust jar lids and process.

 

Raw pack method

Pack the corn loosely into hot jars, leaving one inch of headspace. Add one tsp salt per quart. Ladle boiling water over corn, maintaining one inch of headspace. Remove air bubbles and process.

 

Freezing corn                                                                                                                  

Corn freezes beautifully if you have the freezer space for it. Before freezing, blanch your corn and cut the kernels off of the cob. Pack corn into freezer bags or and leave 1/2 inch headspace for the water in the corn to expand. Store at 0 F and eat your corn within a year.

Freezing corn on the cob     

It’s very hard to make good quality frozen corn on the cob. The problem is that corn contains enzymes that degrade flavor and odor during frozen storage unless these enzymes are inactivated through blanching. But in order to get at the enzymes in the cob, you have to blanch the corn for so long that the kernels get overcooked. The Ball Corp. publishes a recipe for freezing corn on the cob with a blanch time of eight to ten minutes in their Blue Book of Preserving. This recipe will take care of the problem enzymes, but won’t taste great. Also, frozen corn on the cob requires a lot of freezer space considering the small amount of edible product.