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I have bought a 5l container of olive oil which is impractical for daily use. I intend to decant it into something smaller but I'm not sure what to buy.

I know that olive oil is affected by light and temperature. However particularly on light I don't know whether a green bottle is enough or is it better to block all light? How long does it take for light to spoil it?

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    Where are you planning to keep the bottle? In a normally closed cabinet or sitting on your kitchen windowsill? Jul 22 at 16:51
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From my research on this, it sounds like you should be minimising the following as much as possible (two of which you've mentioned in your question):

  1. Exposure to light
  2. Exposure to heat
  3. Oxidisation

To avoid this, it sounds like the best option is a fully opaque, thick-walled vessel, that is sealable. This article on the Kitchn recommends a ceramic cruet, which seems like a sensible choice, but sounds like anything along these lines would work. So if I had the choice between tinted or attempting to block all light, I'd block all light.

Even storing in these conditions, most of what I've seen says it is ideal to consume within approximately 3 months of opening (some sources say a little less, like that Kitchn article which quotes 1 month, and some say a little longer - around 6 months) - though unopened oil should keep for about a year or 2. I don't know that it's possible to say how much more quickly the oil would go rancid in a clear container, however, I think leaving it out for 6+ months will have an impact on flavour.

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    Two years is too long. I never buy oil more than year after its pressing date, ideally less than six months. Stores will still sell it until 18 or 24 months, but even unopened olive oil can start to taste like crayons after this long, and buying it that old can be a bit of a diceroll.
    – J...
    Jul 22 at 16:16
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    @J... I agree that olive oil degrades and loses its properties with time, and after 12 months from production it shouldn't be purchased, because it has lost many properties. However the fact that EV olive oil tastes so bad ("crayons") after two years unopened is really a symptom of either very bad quality (fake EV oil?) or really bad conservation. I've regularly kept sealed high quality EV olive oil cans for 2 or 3 years in my cellar and never had any problem, besides having a less tasty oil (I use them for cooking instead of dressing and there is no real difference there). Jul 23 at 11:06
  • @LorenzoDonati--Codidact.com In your cellar, perhaps. From the supply chain, it can be a dice roll. It also depends on how much "less-tasty" bothers you. Really, there's no reason to cellar olive oil. It's only good fresh and gains nothing with age. I just try to buy as fresh as possible, and only as much as I'll use in a month or two. It's not something to stockpile.
    – J...
    Jul 23 at 11:16
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    @J... I totally agree with you. Here in Italy there's a say that sounds like "Old wine, new [olive] oil.". It's happened to me often because distant relatives in the oil business send it to me as a gift regularly and often I don't manage to consume it all. As I said in my comment, it's not that the oil cannot be made last for many years if you take care of it appropriately and for frying things you don't really need the newest oil, since the temperature is going to alter it anyway. Jul 23 at 11:23
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    @J... Of course, that goes without saying. However we don't always have that option, for whatever reason. So, once you do have got too much oil, it is useful to know you have a third option besides either gulping it all down in a year (or so) or throwing it away altogether because you think it's no longer edible or completely crap. Jul 23 at 12:06
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Get a darkened glass bottle - can be dark green or amber-colored. Amber-colored filters out better than green, it is easier to recycle and produce (therefore, cheaper), that's why we very regularly use them in pharmaceuticals.

The most important things for you to focus on, though, are temperature and oxygen. Your bottle must have a well-fitting cap, bung, or cork and you need to fill it with the least headspace possible. After filling, keep it in a cool and dark place, like a pantry or cabinet that doesn't go very frequently or for extended periods above 27-30C

If stored correctly, your oil should be good for around 2 years. It might still be usable after this, but you need to check for oxidation after opening

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Let me state a premise.

You can preserve olive oil in the original, sealed, metal can for years without much harm, if stored in a cool place (between about 5°C and 15°C) with few temperature variations.

I did it for years with extra-virgin (EV) olive oil. The only problem is that the oil will lose many micro-nutrients (especially vitamins) and some of its organoleptic properties (less tasty). However, it will still be good and have a fine taste nonetheless.

Now to the point.

The worst enemies of olive oil in day to day use are light, temperature variations (and high ambient temperature) and air ingress in the container.

As for light, a very dark green glass bottle is enough if you keep it in a closet where light can't enter. Depending on how much oil you consume, you should consume it all in a couple of months, before refilling.

Always clean the bottle with very hot water and heavy shaking and let it dry before refilling. You could (I don't) use a drop of dish soap to clean the residue from the bottle, but you must be sure to wash away all the soap residue very thoroughly.

Refilling a bottle from the can with new oil before the "old" is not finished may increase the chance it goes rancid. So avoid that, especially if a bottle (1 liter) of oil lasts you more than a month. In this case it's probably better to use a smaller bottle for everyday use.

If storing the bottle in a closet is unfeasible or impractical, you can improve its resistance against light by wrapping it with aluminium foil. Some very high quality EV olive oil is sold here in Italy with bottles that are already wrapped in alufoil.

It is better to keep the bottle tightly closed with an airtight cap. However this is somewhat impractical. If you use a small bottle, you could afford some kind of "beak-caps", which let you pour oil in minimal quantities and still keep the bottle closed (but not airtight).

This is an example:

enter image description here

Since you asked for some numerical data, I give you those from my direct experience. I get EV oil in 5L metal cans. Once opened, I keep the can in my apartment pantry, which is not particularly cool (26-28°C in Summer), for about 6-7 months. It's not ideal, but the oil never got bad.

I use the can to refill a small, very dark green bottle (500ml) with a "beak-cap" similar to the photo I posted, which I keep near my kitchen table, so not inside a closet, but not in direct sunlight. I perform a refill about once every 2-3 weeks.

The setup is not optimal, but it is convenient and practical. Never had any kind of problem: no rancid oil, no bad taste, no lessening of the taste or perfume of the oil.

Note: I've been exclusively using EV olive oil for my entire life, and so my mother's family (my granddad was in the olive oil business). By exclusively I mean, the only fat used for cooking, frying or dressing, with the very rare exception of the occasional butter.

It's a very expensive product, but it's worth any drop of it. It's probably the best edible fat under any aspect. The ancient called them "the green gold" and sometimes you here that expression still used here in Italy from people knowledgeable in the field.

Beware, though, that you should buy EV olive oil, not plain olive oil or other olive oil products which are not marked "extra-virgin", which are far inferior products.

Be also aware that there are lots of fake products, especially some fake "made in Italy" ones. They dilute normal (non EV) olive oil with other kind of oils and if the color doesn't end up resembling that of a variety EV olive oil they add up colorants (e.g. chlorophyll).

High quality "made in Italy" EV olive oil (made with Italian olives) is quite expensive. You won't find any under about 8-10 EUR per liter (retail) here in Italy. Anything under much lower than that price is highly suspicious.

Even if it's not fake, it may be "made in Italy" but using olives coming from abroad, or it may be EV oil only bottled in Italy. If you are lucky, you get a fine product anyway, although not high quality (e.g. it would have less good properties, taste not exceptional or be more prone to go rancid). Otherwise you may end up getting some real crap, although you may be unable to tell the difference by just tasting it, unless you are a bit of connoisseur.

EDIT

After some research prompted by comments in the whole thread, I found a very interesting PhD thesis about olive oil, that in part address the storage question.

"Innovative techniques improving the olive oil nutraceutical quality and the extra virgin olive oil shelf-life" (PhD Thesis), Nari Anita, University of Pisa (PDF)

For further reference, here is the link to the portal of the university relative to that thesis.

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    Instead of the aluminum foil, I try to select a bottle that fits in my cabinet, so it’s not exposed to light unless I actively take it out to use.
    – Joe
    Jul 22 at 20:34
  • @Joe Yep, that's completely fine. The alufoil trick is really useful if you are in a situation where you have no closed cabinet or none near your kitchen table. Jul 23 at 9:59
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I had the same problem. Here's how I solved it. First, I distribute 5 L of olive oil into a bunch of mason jars. Second, I put them in the fridge. It is a dark place, and the oil preserves well there. In my experience, it tastes great for at least a year after I do this.

Interestingly, it congeals while refrigerated. That's why I use a spoon to scoop out when I need to use it. It melts very quickly.

Some further information here

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  • That's not really a good method. Letting the oil cool down so much it solidifies will make it lose much of its good properties. This is only acceptable if you can't store it in a cool (~10-15°C), thermally-stabilized place, like a cellar. Between storing it at 4°C (like in a fridge) or at 25°C I'd choose the latter if it is a fairly stable temperature and still not exposed to light. Jul 23 at 10:38
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    @LorenzoDonati--Codidact.com Interesting. Maybe I will sacrifice a small bottle to the olive oil gods and do a long term experiment to compare frozen to cellared to see. From a chemistry standpoint it's very rare that cold accelerates spoilage, but I suppose it's possible.
    – J...
    Jul 23 at 17:33
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    @J... See the edit of my post. In that PhD thesis, at page 105 I found: "This indicates that even storage at low temperature cannot avoid the loss in positive sensory attributes characteristic of EVOO (Bertuccioli et al.,2014).", although it states that the storage at 6 °C in green glass bottle was better than the other methods analyzed in the thesis (If I got it right). So I remembered well: there are some perceivable changes. Probably I shouldn't have said "much of its good properties", but "some" in that comment. Jul 23 at 18:05
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    @LorenzoDonati--Codidact.com Well, of course, nothing stops the relentless advance of time, but the GG6 sample (green glass@6C) was by far the best of all the storage options tested. "In fact, the oil stored in GG at 6 °C mostly preserved positive attributes [...] Moreover, GG6 maintained the highest BI and did not show defects at the end of storage, further suggesting that storage in GG at a low temperature (6 °C), could represent a promising storage condition to slow-down the oil degradation during market storage."
    – J...
    Jul 23 at 19:11
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    @LorenzoDonati--Codidact.com Well, the reference was a fresh, brand new bottle, so yes, time is unkind no matter what. It's just a matter of degree. I'll have to read this paper in more detail, but thanks for the link!
    – J...
    Jul 23 at 22:38
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Summary: a wine bottle and a matching vacuum pump (and/or marbles).


Wine has many of the same issues with storage. I occasionally enjoy a good dry red, but that is infrequently and only about half a glass at a time. What to do with the opened bottle?

  • Wine comes (mostly) in coloured glass bottles, which protects against light (more about that later)
  • I store it in a dark cupboard on the cool side (away from the equator's direction) of the kitchen
  • I use an air pump to create a partial vacuum in the headspace
  • Bottles are almost all 750 ml - usable but not too big

So I can drink from a bottle for around 6-8 weeks. Yes, oxidation does start to affect the wine, but much less than if it were simply stoppered up. And some wines do well with a little bit of "breathing", so it has never bothered me.

Another way to displace air from a container is to drop in (clean) marbles (the spherical glass toys - does one still get them?) to take up the space of the decanted liquid, then stopper up. This is actually done to store e.g. opened champagne for a few days, as the vacuum pump would "suck out" all the bubbly otherwise. (Seems like a bit of a chore to clean up the marbles after use, though...)

What colour wine bottle? This is my experience with a single datapoint (anecdote, so take with the necessary pinch of salt). I was interested in reusing the same empty wine bottles in a "passive solar water wall" (use your favourite search engine if you want to find out more about the concept). However, I was concerned with algae growing in them - the wall should be exposed to as much sunlight as possible, but sunlight fuels the growth of algae (as seen in white plastic bottles I use as a drinker for backyard chickens). So for my experiment I took the lightest-coloured green wine bottle I had available, filled it with plain tap water, and stoppered it up with a cork wrapped in plastic food wrap (to get a somewhat more air-tight seal). This I placed in an equator-facing window, which gets full sun throughout the day. After a year there was still no algae growth, no specks floating in the water, and the water did not smell "off" (not very scientific, I know). So I think any handy coloured wine bottle would be just fine to protect against light (as others have stated, you could always wrap it in some opaque material and/or store it in a cupboard).

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    About the marble thing: you should really be sure that the glass they are made off is ok for contact with food. Glass is mainly SiO2, which is inert, but to give glass its properties some additives are used in small percentages. Some additives, such as lead, are toxic and may leach in the food. AND THIS IS PARTICULARLY DANGEROUS if the contact is prolonged. Jul 23 at 10:57
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When shopping large quantities of olive oil for regular household use I would recommend to go for a brand that is using bag-in-box packaging instead of the common tin containers as this allows to dispense oil as required while avoiding oxygen contact of the stocked part entirely.

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  • That is most probably some low quality oil. So the advantage of not having headroom for air is likely offset by the lower quality. I've never seen EV olive oil sold in Italy in such a container. Not even the lower brands. Jul 23 at 10:42
  • @Lorenzo Donati: I agree that the BiB is not yet a very common packaging for olive oil, but when it is used then (at least in the german market) rather for organic and premium qualities than for the low-end stuff.
    – J. Mueller
    Jul 23 at 17:35
  • See the edit in my answer. Effectively it seems that plastic containers are starting to being used for EVOO (outside Italy, I guess), so I may concede it's not automatically a sign of bad quality. However, that PhD thesis I linked to states (p.52): "[...]the storage of oil in tin containers and dark glass bottles is the most adequate packaging material because these containers show the greatest stability against oxidation, while polyethylene containers and clear glass bottles show a significant loss of quality during storage (Gagouri et al.,2015)." So, not ideal. Jul 23 at 18:14
  • @LorenzoDonati--Codidact.com The whole paragraph is about PET “bottles” (including clear ones) and doesn't deal with BiB at all. Importantly, if you look up the original reference (Gagouri et al., 2015), you will see that while there are measurable chemical differences, there really isn't much of a difference in organoleptic qualities between the different packaging and those are dwarfed by the difference between fresh and stored oil (no matter how it is stored).
    – Relaxed
    Jul 24 at 7:52
  • @Relaxed Sorry, but I don't read that paragraph being only about PET containers. It talks about containers in general (although non specifically about BiB). In a previous paragraph it also ranks the various plastic materials wrt oxygen permeability. The sentence I cited appears to be just the summarization of the previous paragraphs. Anyway, in a previous paragraph a "clear PET covered with aluminum foil" container is cited as part of the comparison, so a combination similar to BiB (light protection + plastic in contact with EEVO). If I can find time I'll look for that reference (Gogouri). Jul 24 at 9:26
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For many years, I did the same as what my mother did— I kept a smaller bottle sold for olive oil, and refilled it from a large can of olive oil.

The reason is, it has the little plastic insert in the bottle so it doesn’t pour too quickly, and it’s a dark green glass, to prevent the light issues. (But I keep it in a cabinet, so it’s only out in the light when I’m using it)

I never worried about the can of oil. I takes me about a year to go through it, but I’ve never noticed any adverse taste to it in that time.

Many years ago, I got an olive oil dispenser like Alton Brown used on Good Eats. It’s a stainless steel cylinder with a flip lid that you activate with your thumb, and there’s a plastic insert with a pour spout. (It looks like this, but I don’t think that’s the same brand) I love it, but a word of caution— if you overfill it, the oil will push enough to eject the whole plastic insert. I move my thumb to the plastic insert when pouring.

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  • (+1) for your bottle strategy. However, that metal can is really useful only if you use a lot of oil, for example if you cook really a lot and have to refill it daily. It's really a restaurant thing, unless you are a cooking maniac that goes through a liter of oil in a few days! :-) It is really not indicated for storing oil for everyday use otherwise: too much air ingress and headroom and too few heat insulation if you don't keep it in a place with no stable temperature. Jul 23 at 10:48
  • I’ve gotten enough glass bottles of olive oil over the years (as I get mid-grade stuff for cooking in the cans, and get smaller bottles of extra virgin oil for salads and such), that if I had saved them, I could’ve emptied the cab into a bunch of bottles.... but I’ve not noticed enough degradation to have to worry. And pouring the oil itself would aerate it some, I would expect
    – Joe
    Jul 23 at 13:10

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