They used to say if you wanted sweet corn, you’d better put the water on before heading to the market.
In years past, sweet corn had a much shorter ‘shelf life’ than it does now. When picked, the sugars would quickly turn to starch, and sweetness would be lost.
Over the years, sweet corn has been selectively bred to yield sweeter ears, that also hold their sweetness longer.
In fact, the history of corn is incredibly interesting. Over the course of several thousand years, corn has been bred from teosinte, a grass variety, to the incredible sweet corn, packed with sweet, juicy kernels we know today (yes, corn is considered a grass!).
I’m a sucker for numbers and data, so I decided to put our sweet corn to the test.
I took several ears of corn from the same harvest and began my quest.
First, I wanted to see how it measured up to an ear of corn from the supermarket. I popped in on my way home from work and began to examine the corn. I picked an ear that would be as similar as possible to something you’d get from our market: a comparable size, one of the freshest looking ones in the bin, that didn’t look like it had been handled a lot by other customers or peeled back (unless you’re going to eat it right away, your corn will dry out much faster if you’ve peeled back the husk!).
Out came the refractometer.
I peeled the ear of corn from the supermarket and cut the raw kernels off the cob. The kernels went into the food processor (all except a few kernels for a side by side taste test to see if I could taste a difference). I pureed (and pureed) until I was finally able to squeeze juice out of the kernels. A small pipette of the juice dropped onto the refractometer and it was judgment time. The supermarket sweet corn tested in right around 10%.
I washed up and repeated the process with the first ear from our own corn. Peel, cut, puree, pipe onto the refractometer. Ours measured over 15%! In the taste test side by side, there was an extremely noticeable difference in juiciness, flavor and texture.
To give the grocery store corn a fair comparison, I decided to test our corn periodically over the next 12 days. If the sugars turn to starch, it wouldn’t be fair to test supermarket corn that was purchased that day against ours that was picked the same morning.
Supermarkets don’t often have the capabilities to bring in produce picked the same day. If purchasing directly from farms, they may be able to stock their shelves the same day it was picked. They also may source their fruits and vegetables from produce alliances or auctions, all which may be anywhere from late the same day up to several days in the time it takes to get produce from the field to supermarket shelves. (I also want to be fair here and note that I only tested one supermarket ear of corn. Supermarkets may use several procurement methods and may not have the ability or control that farm markets do to offer the same varieties of corn or from the same farms, meaning every store may carry something different, and even the same store may not have the same quality and consistency day to day.)
I stored our corn, from the same harvest, in its husk in the vegetable drawer in our refrigerator. I repeated the testing at 2 days, 6 days, 8 days and 12 days (the first test being day 0). Day 2 I noticed no difference in the reading. On days 6 and 8 it had dropped to an even 15%. It finally dipped a little bit lower (just under 15%) at day 12. On day 12 I felt a noticeable difference in the texture. The corn wasn’t as juicy and slightly less sweet than a fresh ear of our corn, but perhaps only because I knew this corn was TWELVE DAYS OLD and was expecting for something to change in it!