[DISCUSSION] perception of rancidity

submitted by connect

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?]

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Avatar Okokimup

I can't taste the rancidity either. They say if olive oil smells like crayons, it's rancid; if it tastes peppery, it's good. I bought a bottle of the California Ranch brand everyone says is reliable. It smells like crayons *and* tastes peppery just like every cheap bottle I've tried

connect [OP]

Hmm, I have had olive oil be a bit peppery…but I can get that from pepper… Sometimes people talk as if good olive oil is a life-changing experience, but… I think of the day when someone insisted to me that plain fat, like a hunk of fat from a piece of meat, was supposed to be tasty to chew and eat by itself intentionally. (He was enough older than me that he was giving me some dad attitude as if I were simply wrong because I was younger.) I’d never guessed someone would want to do that. But that was his taste perception somehow.

I don’t think I’ve ever perceived crayon smell.


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

connect [OP]

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.

Avatar BlueLineBae

I read an article once that suggested that rancidity is something you learn to pick up on and that the inclusion of certain preservatives such as hydrogenated oils in US foods means a lot of us have lost the ability to detect rancidity vs people in other countries that don't use these preservatives and food has a shorter shelf life. It took me a very long time to recognize what rancidity smells like, but now that I do, I can smell it in a large variety of items. I've smelled it in dry cereal, corn chips, nuts, oils, etc. sometimes it's stronger and more obvious and other times it's faint. It can have a slightly different smell depending on what's rancid, but that base smell always seems to be the same. Here's my suggestion, and it may sound weird... Go to a Mexican grocer or local Mexican restaurant and get some tortilla chips that they fry in house. Put them in a paper bag and leave them somewhere and forget about them for a few months. When you open the bag again, you will get the strongest whiff of rancidity you've ever experienced. Hopefully you'll know after that, what to lookout for. I don't know what it is about fresh tortilla chips, but damn they get rancid in the worst way 🤮


You know, when I used to go to stores that sell various fancy imported olive oils-- in bottles, I haven't tried the bulk bring-your-own-container ones-- I so often found the oil already rancid that I've just stopped going and wondered how they do business. But, now I wonder if it's like so many things where some people are just less sensitive to the flavor. I have to say, in oils it it's never so bad to me that I refuse to cook with it, but to drizzle it on salad or bread 'raw' would be gross. In nuts, it can really put me off, though, especially if the nuts seem stale in other ways. I'm also not a big fan of nuts generally, though. Rancid butter is another thing and I'll just throw it away. Happens at my parents' all the time because they don't refrigerate it and they live in a warm climate. My mom doesn't care about rancid butter but will complain all night about rancid olive oil if you put it on her salad. So I guess it's complicated. Or just kind of on the edge of being yucky, so other factors can take precedence.

connect [OP] , edited

When I’ve tried olive oils, I’ve always been indifferent to them and thought I almost might as well be using soybean oil. And people will say “you’re not buying a fancy enough one”, but it’s hard to imagine it could taste a dollar an ounce worth of wonderful. I did buy a cheap enough one once to think it smelled like acetone. “You have to get it this month of the year from this supplier who will probably send you a new enough batch and maybe nothing will happen to it in shipping” is tiring to think about.


I don't buy a lot of olive oil now because my family isn't into salads, which is pretty much the only thing I'd use the tasty cold press kind for. For refined oil to cook with, it makes no difference--the taste is very mild and I don't think it matters health wise.


Butter too. Supposedly when it changes color it’s going rancid but it just tastes like butter

Avatar rhythmisaprancer , edited

I understand what you are saying, I don't know that I taste it, even in the same batch that others do. My thoughts are it comes to experience. I don't use olive oil, or butter, alone, just in cooking, but if I sample it, it always tastes fine. But with tea, then ya, it was too hot water, or over steeped. But I do drink a lot of tea. Maybe we both could benefit by going to some tastings. And bring some rancid oil with us to compare? Not sure how popular we would be ☠️