Lacto-fermented Olives

Olives are tricky business. Either you love them or you hate them. I love them, green ones, that is. Black olives, not so much. But I add green olives to my potato or pasta salads and  to relish trays at the holiday time. It never occurred to me that I could ferment them. So, if you have access to fresh olives, or an olive tree, give this a go. Sarah makes it sound so easy, and tasty.

Olives are brined, as opposed to being strictly lacto-fermented. This is due to the multiple brine baths necessary to leach out the oleic acid that the olives contain, and which makes them inedible and bitter. After the oleic acid is leached out, you can do a fermentation with the olives, or just leave them in a standard brine.

Most olives are not sold unprocessed, so to get whole unprocessed olives you will probably need access to an olive tree. There are different varieties of olives, some sweeter than others. I picked from several different trees, and ended up with olives ranging from large and green, to small and a black-purple color. I processed them in the same jar, and in the same manner, so I am not quite sure if the olives would have behaved different if I’d processed them differently. Due to the leaching in the brine, most olives will end up green, or with just a hint of a purple blush, no matter how dark they were to begin with.

How to Make Lacto-Fermented Olives

You Will Need:

  • Freshly picked olives – enough to fill your desired container three quarters full. The olives will expand in the brine, hence the necessity for a bit of leeway.
  • Salt (2 tbsp. per liter volume per brine)
  • Water
  • Time


Rinse your olives thoroughly, most olives grow in dry and dusty areas so insure there is no lingering dust.

Prepare your olives, if you have harvested olives yourself you will want to check each individual olive for a small brown spot, or indent in the skin. This is a sign that there could be a weevil in the fruit. Slice each olive along its length, and through any indented spots. If the flesh inside the olive is discolored, soft, or damaged, discard it. The olive should be quite firm, and have a light green tone to its flesh. There should be no brown lines, or other discolorations.
Slice and check every olive, the last thing you want in your brine is a dead weevil. Do not eat an olive at this point, as they are super bitter.

Put all your checked olives into your large jar or container and cover with warm water, add your salt.

Put the lid on your jar and give it a good shake to blend the salt into the water. Set aside either on the counter, or in the fridge. If you choose to brine at room temperature, use a fermentation lock. Brining in the fridge does not require a lock.

After 3-7 days, the water in your jar should take on a greenish to pinkish tinge. This is from the oleic acid being leached out of the olives. Dump the current brine, create fresh brine, and re-brine your olives.

Brining olives requires patience, and remembrance. It won’t hurt the olives if you forget to rinse and re-brine them exactly on time, it will just mean your olives will take longer to fully process.

Depending on the size, type, and sweetness level of your olives, they will need to be re-brined 7-10 times. I brined mine five times before, when I tasted them, they started to taste like olives and not just bitterness. After the 6th brining they were almost sweet, and after the 7th they were perfect. I did an 8th with a few sprigs of fresh herbs (rosemary and thyme) to add some additional flavors.

I brined mine in the fridge, as I knew I’d be forgetting about the jar. If you are better at remembering things, you can do the entire brining on the countertop. You will get some fermentation happening in the first brining if you do so, later brine changes will not end up fermenting.

After you have brined your olives, and they taste like olives and not bitter disappointment, you can enjoy them in a few different ways. Brined olives can be served as-is on an appetizer tray, pickle tray, or wherever you’d serve whole olives. These olives do still contain the pits, so including them into a cooked dish can be awkward.

A favorite Israeli way to serve olives is hot, and herbed. Thoroughly rinse the brined olives. Mix a small amount of olive oil with rosemary and za’atar (a mix of oregano, thyme, and basil), pour over the olives, and heat the olives on a skillet on the stove top until evenly hot and the herb flavors have blended into the olives. Serve hot, or cold, and enjoy.


To ferment fresh olives, you will need fermentation lids for Mason jars. Lucky you, Fermentools makes them to last a lifetime from surgical steel. Get your own kit, including glass fermentation weights, airlock, and more, at the Fermentools store.


Sarah Dalziel is passionate about DiY skills, knowledge, and self-sufficiency. She was homeschooled K-BSc, and enjoys questioning, researching, and writing about hands on skills and preparedness. Ethnobotany, natural dyes, and self-sufficiency fascinate her. If she isn’t writing about them, you’ll find her dipping yarn into a steaming dye pot, or stirring up a batch of woad pigmented soap. Sarah blogs at, a natural dye and fiber skills blog, and also at, an interdisciplinary skills and writing blog.

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