Preserving "supersweet" sweet corn
New varieties of sweet corn are sometimes referred to as “supersweet” corn. They contain more natural sugars than the older, traditional varieties. The natural sugars also seem to improve the keeping quality of sweet corn. As a result, some people freeze the supersweet corn without blanching and still have an acceptable product. For longer storage (more than 4 months), it is still best to blanch the corn so it will not have an off-flavor.
If you are canning supersweet sweet corn, the corn’s extra sugar makes it difficult to prevent it from turning brown. The sugars in the corn caramelize at the high temperatures at which corn is processed in the pressure canner. If you used proper canning methods, the corn is safe to eat although it may have a brown color.
When canning corn, you may end up with a better quality product if you use a less sweet variety and use the supersweet sweet corn for freezing.