I’ll read how a cooking oil will become rancid, or the oil in nuts, or the oil in whole-wheat flour. But I never notice. I never find that something has now become disgusting in that way.
(Although I’m not crazy about nuts to begin with, and I’ve never had a fresh one from a tree or anything, so it’s possible I’m reacting to something there.)
How much do you notice rancidity? Do the people around you detect it similarly?
Some discussions online mention rancidity in connection with supertasting, but I strongly suspect I am a supertaster because I have to go very light on most bitter ingredients, cut back on sugar in a recipe so it doesn’t just taste like sugar, find too much fat to be gross, and so on. [Reading about supertasting is such a blend of sadness and vindication. You mean grapefruits are genuinely supposed to taste good? And an avocado all by itself? And raw pineapple? Honestly?]
I think it depends on the oil/fat. I think the word “rancid” conjures up the idea that it would taste like pure garbage, but that isn’t really the case. What you are tasting is oxidation (and technically some other reactions, too), and not all flavors of oxidation are “bad” flavors. Sherry, for example, is partly defined by the oxidation.
Most “refined” oils (e.g., soybean, peanut, canola) are going to be fairly resistant to oxidation because they don’t have many compounds that oxidize easily. Something like extra virgin olive oil or flaxseed oil, though, has a lot of compounds that can oxidize. That’s why some oils come in opaque containers, and warn you to keep them away from heat. Some, you even need to refrigerate. If you did side by side testing, you’d probably pick it up. Oxidation is one of the reasons you get rid of old fry oil; the heat speeds up the reactions.
Whole wheat, I can definitely detect the difference, and I’ve definitely had rancid avocado oil before. Nuts, I’m not sure about, but I think the flavor of an oxidized nut wouldn’t really be bad, just not as good.
The taste of oxidation is often described as “wet cardboard”, which I agree with for a lot of things. “Fishy” is another word I’ve seen for oil that’s gone rancid
Interesting that you’d mention fishy. I recently read where some described canola as always being fishy to them.
Is the oxidation bad for you after a certain point in general? I seem to recall, when trying to fry doughnuts and such years ago and things would talk about what was happening with the old fry oil that you mentioned, somehow it was supposed to be not great for you. I remember it would deepen in color, and maybe it could have been described as something like wet cardboard.
I agree about the fishy canola odor, especially around the threads of the bottle where spillover gets exposed to air. The oil inside is fine, but that first whiff is offputting. I’m learning to wipe the threads after pouring.