A Genetic Look at Corn's Sweetness
The sweetness of a corn kernel is determined by its genetic makeup. All sweet corn is a result of naturally occurring recessive gene mutations that prevent or slow the conversion of sugar into starch within the endosperm of the kernel. Different types of sweet corn carry different combinations of these genes, leading to varying levels of sweetness, texture, and post-harvest shelf life. By understanding the genetic types, or genotypes, you can choose the best corn for your needs.
The Main Genotypes of Sweet Corn
- Standard Sugary (Su): This is the oldest type of sweet corn, featuring what many consider a classic "corn" flavor. Its kernels are tender and creamy, but the sugars convert to starch quickly after harvesting, meaning it's best eaten within a day or two. Examples include heirloom varieties like 'Golden Bantam' and 'Silver Queen'.
- Sugary Enhanced (Se): Varieties with the 'se' gene have a higher sugar content and a slower sugar-to-starch conversion rate than 'su' types. This means they stay sweeter longer after harvest, typically for several days. They are known for their tender and creamy texture. 'Kandy Korn' is a well-known sugary enhanced variety.
- Supersweet (Sh2): The shrunken-2 ('sh2') gene is responsible for the sweetest corn on the market, with some varieties boasting four to ten times the sugar content of standard 'su' types. This mutation completely blocks the conversion of sugar to starch, allowing the kernels to remain sweet and crisp for up to 10 days if stored properly. The seeds of these varieties appear shriveled when dry, hence the name 'shrunken-2'. Examples include 'How Sweet It Is' and many of the 'Xtra-Sweet' brands. The trade-off for this high sugar level is a crisper, sometimes tougher, kernel skin compared to 'se' varieties.
- Synergistic (Sy) and Augmented Sh2: These are newer genetic types that combine the qualities of different genes. Synergistic types contain a mix of 'se' and 'sh2' kernels on the same ear, balancing the tenderness of 'se' with the sweetness of 'sh2'. Augmented Sh2 varieties are pure 'sh2' but are bred to incorporate the tenderness trait of 'se' types, giving them high sweetness and a softer texture. 'Trinity' and 'American Dream' are examples of these advanced hybrids.
Field Corn vs. Sweet Corn: A Major Difference
While all the types mentioned above are varieties of sweet corn (Zea mays), they are fundamentally different from field corn (also known as dent corn). Field corn is the dominant type grown in the U.S., but it has high starch and low sugar content, making it unsuitable for fresh eating. It is primarily harvested when the kernels are dry and mature, then used for animal feed, ethanol, and processed products like cornmeal or corn syrup. Sweet corn, on the other hand, is harvested while immature (in the 'milk stage') to preserve its sugar content.
Comparison of Major Corn Types
| Feature | Standard Sweet Corn (Su) | Sugary Enhanced Sweet Corn (Se) | Supersweet Corn (Sh2) | Field Corn (Dent Corn) |
|---|---|---|---|---|
| Sugar Content | Moderate (9–16%) | High (14–20%) | Very High (up to 44%) | Very Low |
| Flavor | Classic, creamy corn flavor | Excellent, full corn flavor | Exceptionally sweet, less "corny" flavor | Starchy, not sweet |
| Texture | Tender and creamy | Very tender and creamy | Crisp and crunchy | Tough and starchy |
| Shelf Life | Very short (1–2 days) | Moderate (2–5 days) | Long (5–10 days) | Long (dry storage) |
| Recommended Use | Quick-cooked, freshly picked, heirloom recipes | Fresh eating, home gardens, local markets | Shipping, processing, canning, freezing, fresh eating | Animal feed, ethanol, processed goods |
How to Choose the Sweetest Corn
When you are at the market, you can’t exactly know the genetic makeup of the corn, but you can use clues to make an educated guess. Look for labeling that mentions "Supersweet," "Xtra-Sweet," or "Augmented" to identify the highest-sugar varieties. If buying from a local farm stand, don't be afraid to ask about the specific cultivar they grow, such as 'How Sweet It Is' or 'American Dream'. For the absolute freshest and sweetest corn, your best bet is often to grow your own from a supersweet seed variety and harvest it at its peak. For those interested in learning more about the genetics of sweet corn breeding, the work of researchers like those at the National Institutes of Health can provide a deep dive into the specific genes controlling this desirable trait.
Conclusion
Ultimately, the question of which corn has more sugar is answered by genetics. While standard sweet corn offers a classic flavor, modern breeding has produced supersweet (Sh2) varieties that contain significantly more sugar and a much longer shelf life. Sugary enhanced (Se) varieties strike a balance between high sugar and creamy texture, while synergistic and augmented types aim to combine the best traits of both worlds. For the sweetest flavor, reach for a supersweet variety. For a more traditional, creamy taste, a sugary enhanced or standard type is the way to go. Your personal preference, along with how soon you plan to eat the corn, should guide your choice. All varieties of sweet corn, however, offer a distinctly sweeter profile than the field corn used for animal feed and industrial processing.
Lists
Best for Creaminess and Old-Fashioned Flavor
- Silver Queen (Su)
- Golden Bantam (Su)
- Kandy Korn (Se)
Best for Maximum Sweetness and Shelf Life
- How Sweet It Is (Sh2)
- Xtra-Sweet varieties (Sh2)
- Obsession (Sh2)
Best for Balanced Texture and Sweetness
- American Dream (Augmented Sh2)
- Trinity (Synergistic)
- Honey Select (Synergistic)
Other Types of Corn
- Dent Corn: High in starch, low in sugar. Primarily for feed and processing.
- Flint Corn (Indian Corn): Hard outer shell, used for cornmeal.
- Popcorn: A type of flint corn with a moisture-rich kernel that pops when heated.
