Oil becoming rancid ...?

Question

If you cook a dish using cooking oil (such as canola) and then let the leftovers sit out for a few hours after dinner, before putting the dish into the fridge WITHOUT covering it up ...

... would it still be able to reheat and eat the next day? I've heard that cooking oil can become RANCID if exposed to AIR. So because I used oil to make the dish, could storing it in the fridge uncovered cause the oil in the dish to become rancid by the next day? Or does it take a much longer time for that to happen?

For that matter, how long WOULD it take a bottle of cooking oil to become rancid if the cap was left open? Would it be days or more like months?

I just want to be make sure it's okay to leave food with oil in out uncovered, and still be able to reheat and eat it later on.

Answer 1

Leftovers cooked in oil will not turn rancid overnight. It will mold before it turns rancid.



Oil used for deep frying will go rancid after many months, or if it's been overheated.



Unused oil in a bottle will go rancid after a super long time, like a year or more.



You can taste and smell rancid oil, so you can throw it away before you try and cook with it. No need to worry about your leftovers going rancid, so enjoy the rest tomorrow! :)

Answer 2

Oil will not become rancid after a couple of hours. Used oil will go rancid quicker, but it really takes weeks or even months. And I usually don;t even keep mine in the fridge. Just in a covered jar on the counter.

Answer 3

It takes a long time for oil to become rancid....Usually it is the oil that is in a bottle opened and sitting in the cupboard....





And why would you leave the cap off...? If that was the case it still would be quite a while..............not just a few hours...............

Answer 4

The food will be fine. Canola oil has stabilizers that keep it from oxidizing even when heating. You can store canola oil for many months open and for years unopened. It is the heating and reheating that breaks it down and you can do this for 10's of times with little degradation or spoiling.

Answer 5

potato chips are cooked in oil and are in the open air for weeks and don't get rancid immediately.

All manner of deep fried foods are left in the air and don't get rancid,

Donuts, deep fried pastries, french fries, etc.

You have no worries on those lines.

Answer 6

B) hydrolyzed. in specific, ester hydrolysis the place the fat/oil 'reacts' with water inflicting fatty acid and glycerol aspects of the fat/oil to cut up up. If the fatty acids in touch are incredibly short chain, then you particularly get a reliable scent corresponding to vinegar.