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Storage of Olive Oil

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On the Home Cooking Board I saw that Costco's Kirkland's 1st Cold Press EVOO was recommended. Went to the local Costco and of course the quantity was huge. There are just the two of us and the ministry to the sick is not that large. I understand the principle of sharing. I do have several questions. (1) Will Olive Oil go bad? (2) Will refrigerating or freezing lengthen shelf life? (3) Are their other ways to extend shelf life? We did not purchase. Wife was at Wal-Mart and purchased Pompeian First Cold Press EVOO so I will need info for next time when this purchase runs out. Who would have thought, buying oil during Hanukkah!

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  1. Yes Olive Oil goes bad (turns rancid).
    Storage can be prolonged by keeping it cool, in the dark, and with minimal exposure to air.

    Freezing something is not the same as putting it in a freezer. That said, it will solidify in the refrigerator, and that will slow the aging, as indicated above. It will also cloud up, and appear to separate. Just bring it back to room temp to use.

    As to the 'minimal air', it would be useful to decant from the 55 gallon drum Costco might sell it in to, say, 750ml wine bottles once you start making a dent in the large container.

    1 Reply
    1. re: SteveT

      Sorry about that. You posted as I was editing my response but you're right on the money.

    2. Yes, all fats go bad (turn rancid) eventually. Light and heat are the enemies of your oil. It should be stored in a dark, cool pantry. Refrigeration will cloud EVOO and I have no idea what happens when you freeze it, but I would not do it. Perhaps someone else has had success with that method.

      1. The sole good solution is buying only as much as you can use before it turns rancid.

        Chilling olive oil invariably introduces moisture into the container if there is air in it; the humidity in the air will eventually condense. And condensation will hasten rancidity.

        12 Replies
        1. re: Karl S.

          The short scientific explanation is in this link which says that refrigerating and freezing does extend the life of olive oil.

          http://www.oliveoilsource.com/scripts...

          I was curious about freezing because I had never considered it before. I don't buy that much olive oil and find my maximum shelf life is about a year without paying any special attention to it.

          This article goes really into the chemistry of what happens when olive oil is refrigerated or frozen.

          http://www.oliveoilsource.com/olive_c...

          Link: http://www.oliveoilsource.com/olive_o...

          1. re: rworange

            Aaack, hit post before I meant to.

            Anyway, no one really says how much longer olive oil kept in the fridge or freezer will keep compared to careful storage on the shelf.

            I have not yet reached the level of food compulsion to devote the next five years of my life buying three bottles of olive oil, keeping one on the shelf, one in the fridge and one in the freezer to test this out. However, it is probably compulsive enough that the thought crossed my mind. However, my need for instant gratification overrulled it.

            One thing I've read about freezing olive oil, freeze it in ice cube trays because once that stuff if frozen, it is very hard to whack chunks off for personal use.

            What I did find interesting is that the shelf life, no matter how you store it, depends on the initial product. Lower grades of olive oil have a shorter shelf life than unprocessed olive oil due to acid content and processing.

            Of all places, Hormel had some of the best info about olive oil storage and shelf life. Whatever you do don't store olive oil in reactive metals or plastic containers. See the Hormel link for more info:

            http://www.hormel.com/templates/knowl...

            While you didn't ask this, Hormel says that flavored olive oils should be stored differently because the fruit or whatever added to the oil might promote baterial growth

            I guess another thing to consider is what you use the oil for. I'd be less concerned about a flavor loss if oil is used for cooking than if it is used for dipping or salad dressing.

            This article really does have some shocking info about olive oil, like some manufacturers will add up to 20 percent cheap processed hazelnut oil to lower costs.

            Also, with the cheaper oils, the way that the olives are harvested matters. These oils include debris like twigs, leaves and even spoiled olives that have fallen to the ground so you have built-in rancidity.

            Also, prior the pressing the olives might not be stored properly and turn moldy.

            Yikes. Thanks for asking. I don't think I wanted to know this even though I usually only buy olive oil from one small boutique local farm.

            I am a little annoyed that he besmirches the name of California oil. However he does say " the term "extra virgin" has no official meaning in the United States."

            How true, how true ...

            Link: http://www.living-foods.com/articles/...

            1. re: rworange

              It is becoming well known that very few olive oils are 100%. I recently found out an easy way to tell...put it in the fridge for awhile, and if it solidifies completely, it's olive oil. If it remains liquid with a little bit of solidification, then there's only that much olive oil in there.

              1. re: coll

                Hm, let me try to be kind...you have been misinformed.

                First, it is not becoming well known because it is not true. I don't know whether you are implying that what is labeled as Olive Oil has an ingredients section somewhere, or that we are being cheated. Either way, you're wrong.

                Second, any number of oils (and fats) congeal at 40F, so would pass your 'test'. Different varieties of Olives, ripeness, filtering, age all affect what happens in the refrigerator.

                I will throw you one bone...there is some tendency for Italian Olive Oil to be bottled in Italy from olives grown in, for instance, Spain. There is no way to know how widespread this practice is. So buy on flavor, not on label.

                1. re: SteveT

                  I got this info from someone who sells Italian olive oil, so he could be somewhat prejudiced. He mentioned the Spanish oil factor, but also said they are adding other cheap oils, maybe soy? I think his point was to look for DOC or they can put anything, I think there is a 50% allowance for non-DOC. Apparently this is a recent problem in Italy with the price going sky high in the last year or two. I'm not an expert, the other people present knew more than me and accepted this, I just thought it was interesting.

                  1. re: coll

                    I'm virtually certain that if it's sold in the US the label has to disclose all the ingredients. Furthermore, if it's not 100 percent olive oil it probably would have to say "olive oil blend."

                    Since Italy is part of the EU, they would have to comply with their labelling laws, which I think are just as strict, and because of allergy and GMO concerns, I'd be surprised if they could get away with not disclosing soy oil.

                  2. re: SteveT

                    As to the origin of the olives -- If you read the label carefully ("product of Spain", for example in the fine print) you can identify the origin of the oil, notwithstanding the Italian name on the bottle.

                    1. re: willow

                      Ain't nothing wrong with Spanish olive oil. I like it better than Italian.

                      1. re: Snackish

                        I think a lot of people remember years back when Spanish olive oil caused people to go blind, I'm not even gonna venture to remember the additive responsible. When our generation dies out, maybe no one will remember when....

                        1. re: coll

                          It looks like it wasn't the oil after all... more likely tomatoes with a toxic level of pesticides.

                          I just read a fascinating in-depth article about this that I can't seem to find online, but here is one from the Guardian in 2001 that tells most of the story:

                          http://www.guardian.co.uk/weekend/sto...

                          Around 1000 people died and nearly everyone was misinformed about the reason. At the time (1981) the Spanish government claimed that the people who fell ill had all consumed blackmarket oil bought from disreputable street vendors that contained rapeseed oil--an industrial product (this oil was never exported or sold at any store). As it turns out, some did and some didn't.

                          In any event, Spain is still the largest producer of olive oil in the world, has the best climate for growing olives and has more producers and varieties than anywhere else... The quality is excellent, especially when you stick to D.O.

              2. re: rworange

                I just got the latest shipment of freshly pressed Italian Olive Oil. It is the first time I am tasting super fresh oil (straight from the fields in Italy directly to my front door). I noticed a bitter taste in between when the fruity and peppery flavors hit the palate. I thought it was maybe a defect. This web site says that the bitterness (slight) is a good indicator that the oil is super fresh. I tasted the oil less than an hour ago and had that question. Where else but Chowhound could I have the perfect answer to my question with just the click on a link? Thanks

              3. re: Karl S.

                In my experience refrigerating olive oil does extend its life. I havent done it for a while, but a few years ago I brought back some unfiltered new crop estate oil from italy - it lasted really well for a year under refrigeration. I buy a lot of oil at Coluccio in Brooklyn, which is an importer and they cold-store their oils until they go out on the shelf for sale.

                Storing the oil in a cool dark place is a good recommendation - I would just add that if you buy it in large containers, rebottling into smaller containers, say, old wine bottles, after opening to minimize air contact is a good idea. I just threw out a liter of oil which has been held too long in a 1/3 full metal can in my closet and had oxidized.