Quite possibly my favorite thing about writing this column is the mountain of reader feedback it produces. I have the best readers in the universe, too. Nearly every letter turns into a love fest, which charges my batteries, making me love my readers all the more.
Do you recall the letter from Pat, who complained of her lettuce turning rusty? I responded that the rust colored stains on lettuce are harmless evidence of the natural breakdown process and indicate that the produce is not exactly fresh. The brown edges and spots can be cut away, leaving the rest of the lettuce perfectly edible.
Well, that question together with my response brought a tsunami of input from readers insisting that Pat’s problem is that she is cutting her lettuce with a metal knife.
Jenny wrote, “While working in a restaurant, a decade ago, I learned to either cut the lettuce with a plastic knife or tear it. I do not know the science behind why metal causes the lettuce to brown but my lettuce stays fresher looking days longer since I stopped using metal knives.”
While this might sound like a plausible explanation for why lettuce turns brown, I’m sorry to tell Jenny and the dozens of others who wrote about using a plastic knife instead of metal to keep lettuce fresher longer—it’s a myth. There is no truth to the rumor.
If you believe your lettuce stays fresh longer when you cut it with a plastic knife, the truth is that it would have the same outcome using a metal knife. The enemy of lettuce is time plus oxygen, not metal. Exposing the inside of a head of lettuce to oxygen is going to hasten its breakdown, whether you cut it with plastic, metal or a laser beam. It’s going to turn brown.
Personally, I blame Tupperware parties for this myth. Back in the 1970s the company came out with a little plastic knife or “corer” that it included with its Lettuce Crisper. The instructions were to cut out the heart of the head of lettuce first, insert a plastic pointy thing where the heart used to be, then store it in the crisper.
Tupperware dealers were instructed to tell party attendees that cutting lettuce with metal would make it turn brown and to combat this horrible waste of money, they needed this plastic coring knife-like gizmo. I believed, I bought and so did millions of others. And here we are all these years later—many still believing this vintage piece of culinary lore. I’m convinced it was nothing more than a brilliant marketing ploy.
There are lots of ways to retard the lettuce dying process so that it stays fresher longer. Wait to wash it until you’re ready to use it; store it in a sealed glass container; wrap it in a paper towel to wick away moisture; keep a Bluapple ethylene gas absorber in the produce bin of your refrigerator—all excellent tips with provable results. And the mother of all tactics that will keep produce fresh—at least long enough to use it up—is to vacuum seal it by removing all of the oxygen, which is the arch enemy of fresh produce.
And with that, I’ll close by encouraging you to write to me. I enjoy knowing your feedback, but most of all I thrive on just knowing that you’re there.