Chopped onion storage

Question

I want to know how I can store chopped onions for 2 weeks? I have a cook-out coming up and I need to get ahead of things.

Answer 1

How much onion? It doesn't take much time to chop onion. The only way to store chopped onion for 2 weeks is to freeze. However, once thawed, the texture will not be good. The best answer partly depends on what you are going to use them for. I would say a day in advance is the most you will probably want to do. If they are going to be a raw condiment or part of a salad, you will want them freshly chopped.

Answer 2

Oh my... no.

I routinely chop onions, wrap tightly in plastic wrap, not to smush anything, but to remove as much air as possible before sealing, then put them in a sandwich bag, the kind with the line across seal, not a loser zipper, again removing as much are as possible before final seal.

They last easily two weeks, no sign of anything until at least three and that's just puckering in the surfaces. Even that holds off if I open them once or twice and redo the plastic wrap and sealed bag.

If the onions are bigger pieces: "large dice" (typical cook-out style) or cut rings making lengths one might plan to caramelize for soup or steaks, I wager getting almost all the obvious air out could be tough though, so might be difficult to stretch two weeks with no sign of anything at all. But perhaps opening and resealing a few extra times would solve that.

I will say though, the air removal seems critical to me, and the use of a non-zipper locking bag, also airless. The opening, I believe, and re-removing air actually removes not air that seeped in somehow, but outgassing from the onions themselves. Almost as important to remove, but likelier to cause the kind of cosmetic damage I mentioned, not provide both bacteria and the air for them to breathe.