You will know when it is bad. Rancidity is a really specific scent for me.

Agreed, you'll know. I thought buying a huge tub of olive oil at Costco was a great idea but it definitely went rancid before I could finish it. The word *rancid* seems too strong - it wasn't appalling, it was just definitely off and not a lovely flavor I wanted to add to my food. I keep my big containers of olive oil in the fridge now and transfer to a smaller container for everyday use.

Fridge is a good idea. Some oils are particulary prone to rancidity - nut oils for example. Disposal? Just throw it in the trash or mix in in with scraps and feed it to the wild critters.

Olive oil definitely can go rancid, and it can happen in less than a year if circumstances are wrong. (What is wrong? I don't know exactly, but it is probably correlated to some combination of the amount of exposure to air, heat and light.) The smell of rancid oil is often compared to the smell of cardboard boxes, which in my experience is helpful and accurate. Kind of woody and astringent. It also smells like some paint products, likely because those paint products contain rancid oil (such as linseed oil-based paints).

Eating rancid oil mostly likely won't kill you, but it leaves a taste in your mouth as if you just chewed your way out of a moving box, and the digestive effects might impinge upon your social activities in the short- to medium-term.

Before I started using quarts of oil per month, my solution to this problem was to keep olive oil in the refrigerator. Yes, this can cause the oil to solidify, however if you take it out of the fridge a few minutes before you need it a sufficient amount will have thawed such that you can pour it into your recipe. (Holding the bottle in your hands for a couple of minutes can speed up this process.) I take a similar approach with truffle oil, which I use very infrequently.

Wow, someone was reading my mind! I just got a new freaking bottle of organic evoo and non of my salad dressings were tasting right and I smelled and tasted the oil and I do believe it's spoiled =( I just tastes like bad olives. Yuck...good thing my store will take it back!

I store fragile nut oils in the fridge, but my hu;band and I have no trouble going through a few quarts of olive oil in a year. We cook almost every meal at home, and use olive oil in almost everything.

As far as I've noticed, we've never had oil go rancid on us, but, as I understand it, fats go rancid with exposure to frequent fluctuations in temperature (especially heat, of course) and also exposure to moisture. (I had been storing a jar of ghee in the fridge and then decided it was too annoying to chisel out a hunk, so I started keeping it at room temperature. The condensation caused the ghee to go bad quicker than it ever had before.)

We keep our large jug of olive oil stored in the back of a dark cabinet and take it out to refill our smaller bottle of olive oil, which does get exposed to more heat and light, but we use it comparatively often, so it neither bottle ever gets a chance to go bad.

This is why I buy my olive oil in smaller amounts from my local food co-op.

What about if the EVOO is an unopened bottle, kept cool and in the dark? How long do you think it'll last

Never seen it go bad prior to opening, if stored cool and dark.

The rancid taste comes from oxidation, which begins immediately. I notice it beginning with oil that's only a couple of weeks old.

Macadamia nut oil does not oxidize, and has a high flash point.

If you happen to have an old oil lamp, or even a new oil lamp in fact, rancid olive oil makes a good fuel source, and burns slightly better than fresh olive oil, but both make good fuels for oil lamps.

Hi I'm new to this website. I was asking if olive oil once exposed to air can become rancid.All comments were appreciated. The olive oil was used to coat eggs for longevity. Watching doomsday preppers, Kelleene showed to coat eggs in oil and store in a cool, dark place. Well the problem was that I didn't hear what type of oil used and since my family's favorite is oo that is what was used. I watched the program sometimes later and discovered that she used warmed mineral oil. Even though cold pressed oo was used, the eggs were stored under the bed 6 weeks ago. I decided to test them by cooking and they were fine. But now I know to change to mineral oil. The eggs will be used before too much longer and will use the other. The comment posted by ENDLlN3 I find very useful if the oo ever goes bad.

I think olive oil would last forever if stored properly in a cool dark place but you may forget that it;s there, so if you use it a lot and purchase a big bottle, cut the heel out of a dark sock and cover the bottle with it; therefore it is not exposed to light. The other good idea is to transfer it to a smaller bottle, but cover that as well. ENJOY...It is very good for you.
killeen