How To Cure Olives

I adore olives. So much so that I’ve planted three trees – Arbequina, Leccino, and a new cultivar called Universal out of the breeding program in Yalta, acquired via One Green World.

Side note: you know how OSU does research programs on various genera to test things like cold hardiness and drought tolerance? Well, they’re about to embark on some trials of olives which I hope will be enlightening and will help to further the industry here. Check out this interesting article in Olive Oil Times from May of 2019. And here’s a link to the Olea Project!

Ok now back to the business at hand. Portland is a reasonably decent climate for olives; there will be variation from year to year but for the last three years, I have managed to successfully cure olives harvested here in the Rose City.

Thanks to this guide from Nichols Garden Nursery, I have a method which I will detail for you in this post.

Step 1: Harvest

In the Northwest anyway, olives are ready for harvest around November. They can, and sometimes do, stay on the trees for longer, but you’ll be battling bird predation (starlings, mostly) as well as the elements, and you want to get them nice and fresh.

Last year I went down to Arizona and visited Queen Creek Olive Mill, where I took the “Olive 101” educational tour and learned quite a lot about how olives are harvested and what difference it makes if they are green vs purple vs black. Basically, it comes down to flavor in oil production, but for our purposes, with salt brining, you can mix them all together regardless of what color they are at harvest and they will all be lovely.

So, pick your olives before the starlings get them and before they fall off the tree.

Just harvested, November 28, 2018. Frantoio variety.
Just harvested, November 29, 2019, unknown variety. Note much more green! This doesn’t matter for salt brining.

Step 2: Water Bath ~ 10 days

Ultimately with salt brining, you’re immersing olives in salted water. But before we do that, we need to soak them in plain water for several days to soften them and reduce their inherent bitterness.

Wash your harvested olives well, and then put them in plain tap water in a suitable container. You will need to change this water (and rinse them) daily for a few to several days. Nichols Garden Nursery’s document linked above says that this should be a 10-day process; I can tell you from my own experience that sometimes, you need fewer days.

What you’re after is for the olives to achieve a softness and a slight darkening in color over the course of their water bath. You’re leaching bitterness, basically. Some factors might contribute to a lessening of the number of days: if the olives are wrinkled from summer/fall drought when you harvest them, they’ll need about half the number of days (so, like 5 instead of 10). If they are harvested later in the season, I’d say that the weather and elements will help with the process of leaching, so if you harvest in late December, figure on a few days less. If you harvest in January, or even February, or later still, cut back the number of days by 2-3 days per month. If you harvest really late, like, April or May, you may not need to leach at all! You gotta play this part by ear a little bit. Or rather, by feel. You’re looking for a softening of the fruit and a color change from bright green to a dull “olive” green.

Here’s what they should look like after soaking in water for 24 hours:

Olives get this foamy stuff on the top of the water after soaking for a day.

So what I do when I rinse them each day is I clean out the sink and set up a big colander:

Then pour them into the colander:

Then rinse with water, and pour them back into the container I’m using to soak them, and refill with fresh tap water.

Step 3: Soak in Salt Water – 4 weeks

When the olives have soaked in the plain water enough, it’s time to transition to salt water. Look at the color difference between these, and the pics above – see how these are much more dull and the above pics the green ones are still really vibrant? Dull = ready for salt. You’ll feel this too – they get a little more soft.

The salt water solution is 1 cup salt (I use either kosher salt or canning/pickling salt; shoot for non-iodized salt) to 1 gallon water. Cold water should absorb that much salt easily.

Then when you put the olives into the salt water, some will float. Don’t worry.

Here’s a comparison shot of what this new batch looks like, having just put them into salt water, vs last year’s cured olives that I still have a few of (in the bowl in front)

Right about the same color! This is how you know it’s time to get them into the brine.

Ok now you’re going to change this salt water once weekly for 4 weeks. Does that mean three changes? Or 4 changes? Again, I want you to feel this out. I would say it’s 3 changes but you can do 4 if you want. It won’t hurt them, and it probably won’t make them overly salty.

What I do at this point is put a date on them, so I know when to change the salt water and when I should consider them done.

The ones in the steel stockpot are still in plain water, but the ones in the plastic container have transitioned to salt already.

Step 4: Transfer to 1/2 strength brine and store

At the end of the 4 weeks of full-strength salt water, now you will put them into a half-strength saltwater solution. 1/2 cup salt to 1 gallon water. In this solution, you can store them on the shelf, or in the fridge if you prefer, I find it makes no difference.

The flavor will improve over time and in a few months, you may notice a mild but delightful smoky flavor from your brined olives. I have noticed this particularly with Arbequina but it has also happened over a longer period of time with Frantoio, which generally seems to have larger fruit. So it might be a variety thing, but I think it’s more likely that the larger fruit size makes it take longer for that delectable smoky flavor to develop.

Ok, that’s all for now! Ask me questions if you have em, in the comments.

5 comments on “How To Cure Olives

    1. It *is* easy! In fact, it’s easier here than anywhere else because near as I can tell, we don’t have any olive fruit flies, which are a major pest in the Mediterranean and in California (nor sure about AZ but I would assume yes).
      Even if all you can get a hold of is half a pint, do it cause it’s fun!

  1. Wonderful, Susan! So glad you are sharing your adventuresome gardening spirit and we get to armchair travel along. Three olive trees! Your home-brined ones are beautiful!

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