Last Tuesday, there was so much sweet corn at the farmer's market that it was tumbling off the tables. We bought enough to last the week and cooked half of it that night in a fiesta of buttery bliss. When we cooked the rest of the ears a few days later, the corn was noticeably less sweet and even had a slightly chalky mouthfeel.
What gives? Did we buy bad corn or is there something else going on?
Here's the scoop: When freshly picked, sweet corn is high in sugar and low in starch. However, the longer it sits after picking, the more that balance shifts toward starches. This mutes the flavor and affects it's texture when cooked.
Incidentally, since it's often sold days or weeks after harvest, this is also why corn bought at the grocery store isn't always as sweet as the freshly-picked corn at the farmer's market.
If you can't manage to eat all your corn in one sitting, here are a few options:
1. Buy smaller quantities. Instead of stocking up, buy only what you'll eat in the next day or two.
2. Freeze it! It's best to freeze the corn uncooked, and you can do so either on or off the cob. If it's on the cob, let it partially thaw for about 5 minutes before cooking.
3. Use older corn in a recipe. Though it's not quite as heavenly as fresh corn, corn that's a few days past prime is still tasty and is certainly edible. Use it in corn chowders, corn bread, and other recipes where the flavor of the fresh corn is combined with other ingredients.