Rancidity is oxidation or other chemical breakdown applied to oils and fats which we discusses as keeping water locked up in greasy globules. Kind of. What they mostly are is twisty little chains of oxygen and carbon and hydrogen molecules, but these are kind of the building blocks of life as we know it. So we tend to think of fat and water as two different things, but fat is really just nature’s way of storing water long-term. Water bound to fats in this twisty carbon hydrogen chain are more chemically stable than water splashed on a sidewalk, so the regular water will evaporate in minutes whereas fats will stay on the sidewalk and cause countless people to slip and fall. The example of the banana peel has to do with this as a banana keeps lots of water in fat (that’s what gives the banana it’s incredible flavor—the banana oils coat the inside of your mouth and taste buds, making them more receptive to flavor which is part of why bananas go well with so many other flavors in your mouth, but the banana peel also has a mechanical slippery-mechanism: it’s tactile outer surface debonds with it’s interior surface—lubricated by banana oil—resulting in a truly admirable method of putting a human down ass-first) is only part of it. And it happens that banana oil, when it rancidifies, pretty much develops an alcohol smell which is the excreta
of bacteria, but in cooking, the alcohol evaporates quickly and leaves a delicious aroma. The blackest banana gives a sweet bread. Other fats, like animal fats rancidify and give our noses a danger signal at least in contemporary times. Time was when a man who slicked his hair down with bear fat, rancid bear fat, it was a signal to the ladies that you were a great hunter! Nobody but a great hunter could afford such a precious thing as fat to smooth his hair and oil his skin. He was sending a signal to you ladies: get with me, I am a provider. But perhaps he wasn’t just being sexy in his eagle feathers. Maybe there’s more to bear fat eh? Good thing science is here to confirm.
Fats (lipids) are absolutely essential parts of our diets, we get sick and die without them and lack of them is the nutritional downfall of almost every longterm food storage plan. And most of the time there’s not much we can do about it. This chemical breakdown de-enhances it’s vital nutritional power and can result in “rancid smells” or tastes in the oil. Virgin cooking oil will rancidify generally in under a year. And worse, it’s susceptible to bacterial colonization. All things combined, lipidic fats can turn into something pretty toxic and harmful to us. It’s certainly what makes meats among the most challenging things to preserve and store longterm. And many toxins, unlike the living things that excreted them, can’t be killed. It was never alive to begin with.
It may be some comfort to note that in the case of bacterial colonization, cooking oils can be heated and that will kill them off. The problem is with many bacteria, we’re not so much worried about them as their excreta, and many toxins are just fine being heated. Even more disconcerting are viri which by current scientifical definition are not alive, never were, and yet they can reproduce and get along just fine in levels of heat that no other living thing can tolerate. They aren’t alive to begin with so it’s literally no sweat to them. Above all, keep your oils out of sunlight and cool. Beyond that, figuring out WHY your oil is rancid and what you can do about it might require more of that fancy scientifical testing equipment but fortunately this is one thing Mother Nature sought fit to equip us with: a nose with a distaste for rancidity. Oils, regrettably, are not something that lend themselves well to long term anything. So in addition to other things from the past, look for the return of the grease can. Bacon grease, the oil that comes out of canned tuna (preppers always buy canned tuna packed in oil for this reason plus if you really needed to you could make a really smelly oil lamp with tuna oil), we’re gonna start saving it and using it. Commercially bought oils should be stored and oils derived from our bacon used first before opening a container of stored oil. Oil is something we’ll have to replenish to survive. But all this talk about
rancidity and food is really getting me in the mood to discuss cadavers in some detail.