Experimental Homestead

Making Sicilian Style Fermented Green Olives

big, lively, acidic, rich tasting olives, oh yeah!

big, lively, acidic, rich tasting olives, oh yeah!



I’m going to tell you how to make delicious fermented green olives by the easiest curing method I know of.  One of my many long term projects has been curing olives.  I started because I love them and because they were too expensive for me to eat in the quantities I wanted to.  I figured I could turn those olives growing all over California into something tasty.  Some 20 plus years later, I have a pretty good grasp on the subject.  I’m headed to an olive tasting event this weekend, the Olive Odyssey organized by olive curing champion Don Landis.  I was going to print up recipe cards for sicilian style olives, but thought I’d just save paper and send people here instead.  Besides, now people can bump into this awesome recipe on the web!

What’s so cool about this recipe?  Lotsa stuff.  It is perhaps the easiest curing recipe I know for olives.  There is no maintenance to speak of.  There is no leaching with lye, or water, nor anything else.  You stick ’em in a jar with brine, seal it up, leave it for months and open one when you are ready to eat them.  And of course they taste hella good homeslice!  Big fat juicy, lively, acidic, rich tasting olives… oh yeah.

The downside?  You have to be patient!  Wait, that’s good for you, so get over it!  Oh, and I only know one olive common in California that is really good for this process.  If you’re lucky enough to have access to this olive though, you’ve got a gold mine of potential hanging on those trees in the fall.

That olive is the Sevillano.  It is also known as Queen olive in California, but Sevillano it is and should be.  The Sevillano has been a very popular commercial cultivar, so it is pretty common.  It is also easy to identify.  If you find a tree with many sizes of olives on it, but some of them very large, it is very likely a Sevillano.  If it also has some bunches of very tiny olives, like BB’s, known as shot fruit, it is almost surely a a Sevillano.  The olives are generally oval, but become rounder and plumper as they ripen, turning from a brighter grassier green to a more rich yellow tending toward straw color.  It is okay to use them when they are just beginning to blush red too as in the picture below.    The reason that these work well are several, but the key is the fact that they have a low degree of bitterness.  The finished olives will have some bitterness for sure, but if made with most other varieties of olives, they would be inedible.  The texture and flavor are also outstanding and they seem to have plenty of fermentable sugars.  They also make very good lye cured olives in brine, kind of like the black olives in cans, but many times better.  Yummy like sweet candy is to the unfortunate child of a staunch health food slingin’, kale juicing mother.  Seriously, and that lye ain’t gonna kill ya, I promise.  If I remember right they are ripe in mid November around here, probably earlier at lower elevations with warmer nights.

Sevillano olives are huge!

Sevillano olives are huge!  These might not look all that huge, but those are quart jars you’re looking at, not pints!  Some of these are the size of french prune plums.  Not all Sevillano trees produce olives quite this large and there are usually many sizes on one tree, but they are definitely a large olive, and that is one of the defining characteristics.

You want to harvest the fruits when they reach what is called the milk stage.  When the olives are unripe, they are hard and green.  The unripe olives just scream unripe.  The light green color, the slightly bumpy, hard surface texture, the shape and the bony look they have.  When they enter the straw/milk stage before turning black, the olives really plump up and become voluptuous with oil.  The skin glows and smooths out and the color softens.  The best test though is to pick one, stab into it with your thumbnail, and squish out some juice.  if the olive is ripe enough, it will exude a milky liquor.

Pick the olives carefully to avoid bruising.

Wash the olives and sort over to remove those with olive fly damage.  The olive fly lays it’s eggs in the olive and the larvae eat it from the inside.  Look for small holes and “pricks” in the skin.  If in doubt, sacrifice some by cutting them open to see if there are larvae inside.

If you have a lot of olives, sort them by size and process the various sizes separately.  The smallest ones should finish curing a little sooner than the large ones.  Otherwise, it’s okay to mix sizes.

Wash the olives and pack into scalded mason jars within one inch of the top.  By scalded I mean pour in boiling water, put the lid on the shake it up a bit.  Turn the jar upside down for a minute to cook the lid real good too.  The jars can be any size.  I think you could ferment a single olive in a tiny jar if you could find a suitable jar that small!  Fill jars to the rim with brine made of 1 quart water, to 1/4 cup salt, with 1/4 cup of white wine vinegar, rice vinegar or distilled vinegar. (The vinegar is optional, but it helps shift the ph well into the acid zone, which is safer and seems to kick off fermentation.)   I don’t think I’ve ever added any starter cultures to my olives.  The proper bacteria and yeast seem to be prevalent enough on, or in, the olives.  If you want to though, a splash of whey from the top of a newly opened container of yogurt, or a little juice from a lactofermented batch of vegetables shouldn’t hurt, as long as the quality of the fermented food you get the culture from is high and the culture seems clean.

olive supplies

Supplies… except you don’t need the pice of wood on the right, or the knife, and a plastic lid works better than the usual metal ring shown here. Actually, I just lifted this picture from my old pepperoncini article, but it’s better than nothing.

You can use a new jar seal, or a used one, but used seals should be in very good condition with absolutely no scratches.  You can use a canning ring to seal the jar if that’s what you have, but I much prefer to use a plastic lid and you should too if you have one.  I  buy these white plastic mason jar lids just for fermenting food in jars.  They are fairly useless for most purposes, are not air tight and won’t hold liquids, but they don’t rust, so with a seal underneath, they are a better choice than a ring when it comes to fermentation.  I use this system of: mason jar/seal/plastic lid for almost all of my fermenting now.  It is simple, accessible and it just works for various reasons, which I’m sure I’ll be writing about more sooner or later.  If all you have is canning jar rings, just use them, but the salt and acids will eat them up.  When you put the seal and lid on, the liquid should spill over a bit.  You want to leave very little or no air in the jar.  Screw the lid on firmly, but not super hard.  It is possible to tighten the jar so much that pressure cannot escape, which is not good.  I’ve been doing this for many years now and have never once had a jar break from built up pressure.  It has to be tight enough to keep air from entering back in, but the pressure created by fermentation must be able to escape.  Fortunately, there is a lot of leeway in how tight you make the lid.


Contents under pressure.  The olives will spill over, but unless the lid is extremely tight, the pressure will escape without breaking the jar.

Ok, now you’re going to put that jar of pretty olives drowning in brine on a dish, because it’s going to ferment and spill over.  Leave it at room temperature for a month or so.  Don’t open it!  The carbon dioxide formed during the ferment will push any remaining oxygen out of the jar leaving a blanket of  inert carbon dioxide over the olives.  The liquid level will diminish somewhat and the olives at the top will be left above the liquid.  They are not sitting in air though, but in carbon dioxide.  If you open the jar, you let in air, and most importantly oxygen.  Organisms requiring oxygen will begin to grow in the jar and form a colony on the surface of the brine and on the olives.  If you see that happening, usually as a white scum or film, you have air in the jar and you’ll have to toss the olives.  There is no really good reason to open the jar until the olives are done and you want to eat them, and plenty reason not to.

After about a month or so, the most active fermentation should be done with.  Check the jars for any kind of scum growing on the surface of the olives/brine, rinse the jars clean, tighten the lids pretty hard, and put them away in a dark cool cupboard for another 2 months or more.

I think these olives really develop pretty quality pretty well by 6 months, but I have some that must be around three years old now and they are still excellent!  They are not sterilized, they are not treated with preservatives, they are alive and kicking and full of beneficial bacteria.  The reason the whole thing works is that they have been maintained in an anaerobic (oxygen free) environment with good bacteria and yeasts dominating the acidic salty culture.  Pretty awesome if you ask me.  Certainly don’t open them sooner than 3 months after putting them in the jar.


A cupboard full of peppers and olives fermented in jars.  All of these were packed, covered in brine, allowed to ferment, and then rinsed and put away until needed without opening at any time.  I looked up the date my pictures were taken, and these olives are now over four years old from picking and packing as of today.  I just opened a jar and they are excellent.

I’m sure there is a lifespan to these tasty morsels, but I haven’t encountered it yet.  Eventually the lids will rust through, so that is something to think about.  When you open the jar, be extremely careful not to get any bits of rust from the lid into the olives.  Remove the lid carefully and then gently wipe the rim off well with a damp cloth.

The surface of the brine should not be covered in scum or white film, which would indicate air infiltration and potential spoilage.  The olives and brine should smell, look and taste, bright and appetizing.  The olives floating above the brine might be somewhat darker, but that’s okay as long there is nothing else wrong with them.  After passing the visual and smell tests, the olives should taste sharp, lively, and clean.  The feel and the bite can be tender, but should not be mushy or soft or slimy.  Trust your senses.  If the olives failed to ferment at all, they will not taste acidic and probably will not look very good either.  The fermentation is essential to out compete spoilage bacteria and create preservative acids, so if they aren’t acidic, they should be thrown out, period.

Refrigerate uneaten olives, but use within a few weeks to a month or so.  You don’t want them sitting around long enough that you start seeing white scum forming on the brine surface.  Adding some vinegar, or just replacing half the brine with a light colored vinegar, like distilled, white wine or rice vinegar will allow them to keep much longer because vinegar is just much more preservative than the lactic acid which dominates the brine.  But I dont’ think you’ll need to, because they’ll be so good, you’ll eat them all.  If you must save them for special guests or because they are just too damn good and special to eat, add some vinegar before storing int the fridge for a long time.

That’s it.  That seems like a lot of words for the simplest olive process I know, but I hope you learned a little more about fermentation options too.  Fermenting in jars has the advantage of long storage in those jars, and means that you can put food up in small amounts that you can finish before the stuff goes bad.  That is always my main message to people about fermentation, mason jars are the cat’s knees.

I wrote this post in a hurry, so please let me know if I forgot anything important, or if you have any questions leave them in the comments below.

These olives are richly flavored, zesty and alive. Someone get me a loaf of chiabatta and some olive oil quick!

These olives are richly flavored, zesty and alive.  Someone get me a loaf of chiabatta and some olive oil quick!  And some prosciutto and cheese… and red wine.  And maybe a date. No, not the fruit, a date with a girl silly!  Like a date to eat it with, not a date to eat with it!  I don’t want dates with my prosciutto.  Maybe some gelato and an espresso though.  Can I get some service around here?  I made the damn olives from scratch, geez.

February 14, 2014 - Posted by | Food and Drink Making, Food Trees Fruits and Nuts, Recipes! | , ,


  1. Hi Steven and thanks for the great posts!

    Do you ever add herbs/spices to your final brine? If so, what do you add? I cured olives for the first time this past fall, using the fresh water method described by Hank Shaw on his “Hunter – Angler – Gardener – Cook” blog. They are fantastic! Unfortunately, I can’t harvest olives as there are no olive trees here in the Philadelphia suburbs, but when I saw green olives at the local international produce market I remembered Hank’s article and had to try making them. When the batch was done I kicked myself for not buying a whole lot more! I made two different brines – the one that turned out best was flavored with ramps (dehydrated in the spring – sub a slice or two of your delicious looking leeks), lemon thyme, coriander and Bay leaves. If you do have a favorite brine, please post!

    Comment by petebacher | February 15, 2014 | Reply

    • These olives are really flavorful as they are, so I’m not inclined to add anything. If anything I would think fermented ripe peppers, aka pimentos. Really though, they don’t need anything. Sometimes simple natural flavors are best left alone, or eaten with other flavors. The water leached olives like you made do sort of need a brine. For that type I like light vinegars like white wine vinegar or rice vinegar, some water and herbs- Lemon peel, tarragon, rosemary and bay are nice for that style. The vinegar is important for preservation, but salt can be to taste. I really like those. Generally I harvest the cracked olives in fresh water a little bit greener than the full milk stage too. They are the earliest type of olive you can make in the season.

      Comment by Stevene | February 15, 2014 | Reply

  2. Very interesting. So, if I don’t have access to Sevillano this could work with other olives that have low bitterness? Can growing conditions have an affect on the level of bitterness, or is variety the only factor? Bird sown olives of no known variety grow not that far from me and I’m in an area that periodically has wet weather, late summer/early autumn. I wonder if rainier years would ‘dilute’ bitterness, or just give flabby, disease and pest prone fruit?

    Short of test batches, is there any way of determining the (relative) bitterness of an olive? Please don’t tell me I have to gnaw on unprocessed fruit.

    Steven, thank you for yet another great article. As well as providing an impressive amount of information you also deliver it clearly and eloquently.

    Cat’s knees 😄 ; good luck with that date! Seriously, with all the good you put out into the world I know it must be reciprocated.

    All the best,

    Comment by Polly | March 28, 2014 | Reply

    • he he.. thanks.

      This method could certainly be done with other olives of low bitterness, though the quality will vary. Kalamata is low in bitterness, but is not used for green olives. I’ve not tried it, but the literature often makes a point that it is not suitable for green olives. I can’t give you other names at this point. I’m not sure you can tell by tasting, I’ve tried before and low bitterness olives still taste overwhelmingly bitter in my experience. I know one other tree that is probably sweet enough, but it’s typically low on flavor as well. I’m going to guess that most wildling olives are going to be quite bitter. That’s been my experience. Of course there must be some that aren’t. This recipe is so easy that you might as well just put up small test batches. They could be as small as the little half cup mason jars. Of course they won’t be ready for a long while, but that’s just the nature of the game. There are options for de-bittering green olives before fermentation though, and the sicilian process is really the exception made possible by uncommon low bitterness olives. Sevillano just happens to be not uncommon in California.

      Spanish style olives are treated with lye first to remove some of the bitterness before fermenting. Manzanillo is commonly used, and picholine is also good for this process. You soak them in lye long enough to penetrate the flesh part way, soak them in a few changes of water, and then ferment them similarly. A small amount of sugar can help replace some of the sugars lost with the lye treatment and kick off the ferment, though it is not always needed. a splash of whey or another fermented culture to start things off couldn’t hurt, but it not always necessary either. If the lye penetrates all the way to the pit, it can remove too many nutrients and sugars preventing or stalling fermentation.

      You can also use wood ash paste or wood ash lye for the same purpose, but it generally takes longer to penetrate adequately, unless made very strong (which is a whole other can of cats I won’t open now). When you cut an olive open, you want to see it penetrated about 1/3 to 1/2 way to the pit. it’s a very obvious line. The main issue I’ve found using ash is that the flavor is rather strong and can be unpleasant. The ash has to be very clean. Smouldery fires like woodstove fires make ash that is high in creosote type stuff and will taste very strong. I think there is going to be a flavor difference in species too. There are certainly major differences in the strength of the lye by species. So, quick burning open fires with certain species of wood is no doubt the ticket, but figuring out what will work where is going to require some messing about. I remember reading that oak was used in france, I think on picholine olives. I plan to try using ash more in the future. Not that I’m afraid of using lye, but I prefer not to have to buy food processing supplies and everyone else is afraid of lye. Lye can be dangerous, but it’s poisonous only because of the caustic action when it’s very concentrated. I don’t remember the proportions of lye to water off the top of my head anymore, but that should be easy to find online. There is a UC publication on processing olives that is very useful. It’s sort of bare bones, but it contains a lot of good information and a section on spanish style olives. They sure are good when they turn out right, holy crap! Worth some experimenting for sure. Then if you just make some pimentos to stuff them with… I’m planning to re-write my pepper fermenting handbook soon (it’s still posted on paleotechnics.com in the articles section as of now) and an olive book may be forthcoming as well, though that is something of an undertaking.

      Another thing I’ve done is to slit the olives and soak them in two changes of fresh water daily until some of the bitterness is gone before fermenting. I can’t give you a time line on that though. If it’s anywhere near approaching edible, it’s probably more than leached enough to ferment into green olives. don’t take it too far. A little added sugar should help here, because you’re leaching out a lot of stuff along with the bitterness. I’ve only done this a few times, and I seem to remember some problems, but I’d have to look back in my notes. It’s easy enough and worth a try.

      Processing olives beyond a few of the most basic methods can seem intimidating for a lot of folks, but it’s well worth the time and effort to figure it out, and not as hard as it sounds. They’re great food and can be so delicious. Varietal selection is a big stumbling block, as most are dealing with unknown varieties picked from random sources. Some patience is required, but after a year or two of experiments you’ll know what’s good for what. If you can plant olives, choose classic pickling types like picholine, sevillano, manzanillo, kalamata etc… Don’t plant oil olives unless you plan to plant at least several and make oil. Some are good pickled as well, but some aren’t and they are typically very small. Most table olives can be processed for oil as well though. None of mine are bearing significantly yet, but they are getting bigger…

      Comment by Stevene | March 28, 2014 | Reply

      • I used fresh water to leach my raw olives this year – one or two changes of water daily. I let them go for 30 days, and IMHO they turned out perfect. Taste them for bitterness starting around 20 days if you like. I live on the east coast and used market-bought olives so I don’t know what type they were, though they’re a good size (around 1-1/4″ long).

        Comment by Petebacher | March 28, 2014

  3. I’m fermenting 10 lbs of colossal Sevillano olives from CA right now. I cracked them and removed the pits this time. Usually I leave them whole. I also used slaked lime to help remove the bitterness. They are in brine now and bubbling away like crazy! Can’t wait to see how they turn out. I also added some organic food-grade citric acid. I do this with ripe olives, too. It seems to help with fermentation process and oxidation issue with the green ones. I’ve been curing olives for years!

    Comment by paizleysun | October 12, 2016 | Reply

    • Cool! I’m glad to hear you use lime. I rarely hear of anyone using lime, but have been planning to try it since I burn my own from sea shells and know it’s clean. I haven’t harvested any this year. The olive fly is so bad it’s hard to get good ones anymore.

      Comment by Stevene | October 12, 2016 | Reply

  4. Awesome article!
    Is it possible to ferment store bought already-brined, sliced olives?

    Comment by Raymond | March 20, 2018 | Reply

    • I doubt it, there probably are not enough sugars. Also, starting with something already heat canned is probably a lot different than starting with fresh live cells.

      Comment by Stevene | March 20, 2018 | Reply

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