Sweet Corn – A Summertime Treasure

The long-awaited summer treasure, sweet corn, will be available from local growers very soon.  I am fortunate to have sweet corn growing in our garden but if I didn’t, sweet corn would be at the top of my list to buy only in season from local growers.  Getting a variety I like and biting into an ear of plump kernels bursting with that sweet, corn flavor is well worth the wait. 

Sweet corn is an old food. The specific time when sweet corn originated cannot be pin-pointed.  However, Spanish explorers in the early 1500s found Indians growing corn in East Texas, and the Spanish carried on corn culture in the Rio Grande valley settlements and Texas missions. They ate the grain as a basic ingredient in tortillas, tamales, posole, and atole.  The first known variety, Papoon, was acquired from the Iroquois Indians in 1779 by European settlers. Sweet corn has been ever evolving. Over time, plant breeders have developed sweeter cultivars as well as cultivars with better keeping qualities, flavor, tenderness, vigor, and other characteristics. Sweet corn now comes in several hundred varieties of five genetic types and is available in three different colors: yellow, white and bi-colored (yellow and white).

Genetic Types and Characteristics

The long-grown or older varieties of sweet corn are known as Standards (su).  These cultivars have the traditional sweet corn flavor and texture with sugar levels generally between 10 and 15 percent at harvest. Unfortunately, standard cultivars retain their high quality for only one or two days and don’t generally store well as sugars quickly convert to starch after harvest [1]. Honey and Cream, Silver Queen, Sterling Silver, Jubilee, and Merit are some well-known names.

The first breeding improvement was the introduction of Sugar Enhanced (se) cultivars. Sugar enhanced cultivars contain the sugar enhancer (se) gene that produces ears with sweet, tender kernels. Sugar levels are slightly higher than standard sugary cultivars. The harvest and storage life of se types are slightly longer than standard sweet corn [1].  Well-known SE varieties include Bodacious, Ambrosia, Sweet Temptation, Delectable, and Miracle.  SE varieties are typically used for freezing.

Then along came the Supersweet (sh2) corn varieties.  These cultivars contain the shrunken-2 (sh2) gene. Supersweet varieties have smaller, crisper kernels with high sugar levels and convert sugar to starch slowly, allowing for a longer harvest period and storage life [1] of about three days1. Candy Store, Florida Staysweet, Sugar Loaf, Sweet Time, and Sweetie are some of the Supersweet varieties.

With further development, the Synergistic (syn) cultivars possessing the su, se, and sh2 genes entered the sweet corn scene. These cultivars are sweet, creamy, and tender and have an excellent storage life [1] remaining at their peak for five days before converting to starch1. Allure, Inferno, Providence, and Sweetness are examples of Synergistic varieties.

Lastly, an improvement on the Supersweets are the Augmented Supersweets (shA). They are sweet, tender, and have an even longer storage life [1] offering a ten day window where sugars are at their peak before converting to starch1. Anthem, Obsession, and Patriarch are examples in this group.

Of course, when you’re buying corn, you often only have one choice and it’s frequently not labeled as anything but fresh corn. If you really want a particular variety or want to know the characteristics of what you are buying, talk with the producer at a farmer’s market; they will likely be able to fill you in on the variety or other details.  A seller at a local stand may or may not know the variety and simply sell the corn by a popular or recognized name.  One that I often see used for bi-color corn is ‘peaches and cream,’ a sugar enhanced (se) bicolor that has been around for some time. For a short listing of suggested cultivars of each each gene type, see Sweet Corn by Iowa State University Extension horticulturalists.

Get It Fresh – Keep It FreshEnjoy It Fresh

Despite all the genetic improvements, the trick to getting good corn for eating is to get it as fresh as you can and cook and eat it promptly. When choosing corn, look for ears with moist, fresh-looking husks free of insect damage. Feel the ears to assess the plumpness of the kernels and whether the rows of kernels are fully formed. (Quick fact:  the average ear of corn has 800 kernels, arranged in 16 rows. There is one piece of silk for each kernel.)  Refrain from pulling the husks back to check out the kernels as it is not only bad manners, but spoils the corn for others; opened corn dries out quickly. Once home, store sweet corn in the refrigerator with the husks on or off in a plastic bag; husk on is best but shucked corn may fit in the fridge better. Remember, depending on cultivar, the sugars in corn begin to convert to starch so purchase only what you can use in a few days.

Fresh sweet corn can be prepared in a variety of ways—boiled, steamed, microwaved, grilled—and even raw. The key thing to remember is that today’s sweeter and fresher varieties do not require the cooking time of yesteryear.  Sweet corn can be cooked anywhere from 30 seconds to 3 minutes, depending on how “done” you like it.  Once cooked, it can be eaten directly off the cob or sliced off and used in recipes.

Fresh corn kernels are also great to keep on hand for tossing into salads or other side dishes. Raw corn cut off the ear will last only a day or two in the refrigerator before turning sour. To preserve the freshness, cut the kernels off the cobs and blanch them in boiling water for 1 or 2 minutes. Drain, let cool, and store in a covered container in the fridge for up to five days. Another option is to blanch, cool, and freeze the kernels in a single layer on a baking sheet until hard, and then store in an airtight container in the freezer where they will retain best quality for up to three months.

Lastly, when sweet corn is in season, it is a great time to freeze or can it for eating throughout the year. Corn is one of the best vegetables to freeze because the quality of home-frozen corn is superior to commercial products. Purdue Extension [2] says most sweet corn varieties are acceptable for canning and freezing but recommends the following varieties:
Yellow -Bodacious and Incredible
Bicolor – Temptation, Delectable, and Providence
White – Silver King, Silver Princess, and Whiteout.

For specifics on canning and freezing corn, see the National Center for Home Food Preservation website for details:
Freezing Corn,
Canning – Whole Kernel Corn,
Canning – Cream Style Corn.  
Or
Let’s Preserve Sweet Corn by Perdue Extension
Freezing Sweet Corn:  Whole Kernels by University of Minnesota Extension.

Enjoy and make the most of one of summer’s treasurers.  It’s only a matter of days!
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1
Rupp Seed Inc, 2021 Vegetable Resource Guide:  Sweet Corn Genetic Types

Marlene Geiger

I am a graduate of the University of Nebraska-Lincoln with a BS in Home Economics Education and Extension and from Colorado State University with a MS in Textiles and Clothing. I enjoy spending time with family and friends, gardening, quilting, cooking, sewing, and sharing knowledge and experience with others.

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Easy method for freezing sweet corn

Unhusked cornSoon there will be more sweet corn available than we can eat. I plan to freeze some so we can enjoy that good Iowa sweet corn this winter. Use the easy directions listed below after you have husked removed the silks and trimmed the ends of the corn cobs.

Whole kernel corn: can be frozen by blanching the kernels before removing them from the cob. Blanch the corn for 4 ½ minutes, cool in ice water, and then cut the kernels from the cobs.

Cream style corn: follow the above directions but only cut the kernel tips. Next scrape the cobs with the back of a knife to remove the heart of the kernel and form some “cream”.

sweet cornCorn on the cob: Blanch the ears for the time listed in the chart. Cool the cobs in ice water. If you don’t cool the corn long enough the corn may become mushy and have a “cobby” taste. Cooling the corn requires a longer time than blanching.

Ear size

Blanching time

small ears (1¼-inch diameter)

7 minutes

medium ears (1¼-1½-inch diameter)

9 minutes

large ears (over 1½-inch diameter)

11 minutes

Liz Meimann

I received both my undergraduate and graduate degrees in Food Science at Iowa State University. I love to quilt, sew, cook, and bake. I spent many years gardening, canning, and preserving food for my family when my children were at home.

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