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Can oil go bad?

  • p

If so, how would you know? I noticed a "best by..date" on one bottle, and had never thought about it before.

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  1. Yes.
    It develops a smell and an off taste.
    Some oils, particularly nut oils, go bad faster than others. The problem can be avoided by storing oils in dark, cool places. I put alot of bottles in the fridge, especially if they are oils I don't use alot and won't get through quickly. They congele, but come back to liquid once at room temp.

    7 Replies
    1. re: Aaron

      any food with a high oil or fat content (i.e.: nuts, cereal breakfast bars, whole oils)can easily spoil when not stored carefully at non-refrigerated tempertures. The fats are oxidized, can form free radicals which damage human cells; the rancid taste tells you when oils are spoiled. This is why preservatives are added to many oil rich convenience foods (and ladies, cosmetics!), to keep the oils from oxidizing.

      Best to store properly and use quickly oil-laden products. The admonition "Keep in a cool, dark place" should be heeded. Don't buy a gallon of olive oil at Costco if you're cooking for two.

      1. re: toodie jane

        thanks! the paticular bottle which had the date, also had "keep refridgerated" which I had never noticed on oil- it was a gourmet grilling oil.
        So, basically, it sounds like I would know if it was bad.

        1. re: pamd

          Hopefully - I've noticed that a lot of people don't recognize rancidity until it's so far gone it's horrible and it's bad long before that.

          I think it may have to do with getting used to it. If you've been using a large container of oil steadily, you may not notice the difference accumulating little by little ("gee, it doesn't smell any worse than it did a week ago..."), but if you smell it side by side with a fresh bottle, the difference is stark, If you're in doubt, it might be worth buying a small bottle of something new to double check.

          1. re: MikeG

            this is interesting...I think that because I buy smaller bottles (never transfer it to containers)and use it quite often it's probably never happened to me. I was just thrown off when I saw the date & refridgeration note on that 1 bottle- then of course checked the others.

            has anyone ever found a really good reference for oil brands? how about personal favorites?

            1. re: pamd

              It also depends upon what part of the country you are in. When I lived on the east coast, I found I had more of a problem during humid summers with things that were unrefrigerated going bad (i.e. oil, or flour, etc. getting bugs). In CA I rarely if ever have a problem -- I think because the overall temperature fluctuates less and it is drier.

              1. re: pamd

                Ah, OK, I misunderstood. One thing, if you do want to buy larger bottles (like if you can't find a preferred oil in a small one), it does help a lot to transfer it immediately to smaller jars after you open it. Not being "sterilized" isn't an issue (if they even bother with that sort of thing for oil), it's all a matter of how much air it's exposed to. Fill a couple of smaller bottles near to the top and tightly close, and they'll keep much better than in one large bottle you frequently open and close even if you don't want to give up fridge space to it.

                As for favorites. Basically, I've never really tasted an extra-virgin oil I wouldn't be willing to use, I'm not _that_ picky, so I often buy something that catches my eye, just out of curiosity. But I do prefer oils made from riper olives that lack the astringent bite that so many people apparently like in the very green Italian oils. One Italian brand I'm very fond of is called "Colle Monacesco", put out by Mantova. Despite the apparent place name (roughly, Monastery Hills), I assume it's just a blended oil with a brand name, but it's very smooth and flavorful, and at about $12/liter, not badly priced at all. I use a fair amount of Spanish oil, but couldn't tell you the names offhand. Usually priced around the same. I wouldn't tell someone else they're wasting their money buying more expensive oil, but I've never found enough of a difference to bother paying as much as 2 or 3 times what I pay for my regular ones.

                For general purpose non-olive oil, I use high-oleic safflower oil. It's higher in monounsaturates than the regular stuff (which makes up the difference with polunsaturates), has a high smoking point and is very neutral flavored. Unlike canola oil, it doesn't smell like linseed oil when you heat it. (blech) I tend to get Chinese peanut oil because it has, and I like, a stronger peanut flavor than Planter's. If I know I'm going to do a lot of deep frying, I'm not at all above buying a cheap gallon of corn oil so I can just toss it when I'm done instead of dealing with the hassle of straining and refrigerating - I just don't deep fry that much. If I'm making something special-ish and specific, I'll use more expensie oils too, though.

                I don't use nut oils enough to have favorites. Absent specific info from a source I trust, I tend to go for the "mid-priced" ones figuring to avoid the worst of the lot without overpaying for pretty labels or bottles and imaginative copywriting on their labels. ;)

        2. re: Aaron

          As others have noted, it sure can.

          This past Easter, my MIL was cooking dinner. She'd already prepared several of the dishes in advance.

          When we arrived, my husband noticed that her olive oil had been put into an old plastic maple syrup container. To make it easier for her to pour instead of using that proverbial gallon container.

          He took a smell of it (since the bottle itself looked quite ancient). The odor was awful. It was totally rancid. We took a drive to p/u a fresh bottle (no easy feat on Easter Sunday as most stores weren't open in her area by then).

          We later found out that large gallon tin was not rancid. Apparently, she'd been using the same plastic bottle for ages and never thought to wash it out between uses. Hence how this turned rancid so quickly.

          So, her usually wonderful artichokes and stuffed mushrooms were a complete loss as far as we were concerned (other family members didn't even notice, but we were not about to take chances. You could smell the weird smell coming off of the dishes). Thankfully, she hadn't gotten around to finishing off the broccoli rabe dish, which I happily did for her with the new oil.

          Side Note: Bad garlic was in these dishes too! You should have seen how old the bulbs were. They were beyond sprouted and were on their way to the grave themselves. We picked up fresh of this too :-)

          Sorry for the long reply - getting a bit off topic somewhat but just wanted to point out how bad it can get.

          Laurie

        3. j
          Joyce Goldstein

          As everyone has already noted...ABSOLUTELY! What I notice is an off smell that smells like a mild turpentine to me. I don't have the keenest sense of smell tho. Am I first detecting it when it is horribly far gone or just in the beginning stages. I do try to sniff often! ;-)

          Someone asked about oil preferences -- For cooking I buy the big bottle of Berio regular olive oil that is sold at Costco. I split it with friends (putting it into glass bottles that I wash after each is emptied) so that it is used up fairly quickly. For EVOO I reall like Fairway Arbequinha EVOO. It has a great spicy-ish flavor IMHO. I'd love to know what others here like.

          1. j
            Joyce Goldstein

            As everyone has already noted...ABSOLUTELY! What I notice is an off smell that smells like a mild turpentine to me. I don't have the keenest sense of smell tho. Am I first detecting it when it is horribly far gone or just in the beginning stages. I do try to sniff often! ;-)

            Someone asked about oil preferences -- For cooking I buy the big bottle of Berio regular olive oil that is sold at Costco. I split it with friends (putting it into glass bottles that I wash after each is emptied) so that it is used up fairly quickly. For EVOO I reall like Fairway Arbequinha EVOO. It has a great spicy-ish flavor IMHO. I'd love to know what others here like.