Curing Olives with Lye

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how to lye cure olives
Photo by Holly A. Heyser

Lye. Isn’t that the stuff the Mafia uses to dissolve the bodies of those who’d made an unfortunate choice to use another waste disposal or vending machine company? Isn’t it drain cleaner, a deadly poison? So how on God’s Green Acre can lye be useful in the kitchen?

Relax. I am here to tell you that lye can be your friend, especially when it comes to curing green olives. A good lye cured olive, I have discovered, is uniquely smooth and luscious in a way that brine or water-cured olives can never be. Done right, they can be <gasp!> even better than a brine-cured olive or an oil-cured olive. Seriously.

Let me start by admitting that I was as terrified about using drain cleaner to cure olives as you are. Intellectually I knew it would work, and knew I’d eaten lye-cured olives before, as have most of us: They are those nasty black canned things also known as Lindsay olives. That knowledge, however, did not bolster my desire to do any lye curing anytime soon.

lye cure olives
Photo by Holly A. Heyser

Then I did some research. I’d seen all sorts of references to how the lye cure — actually a cure in water that had percolated through wood ashes, which are a source of lye — being used “since Roman times.” Many hours of searching later, I found that the Roman agricultural writer Rutilius Taurus Aemilianus Palladius is the source of this, in his De Re Rustica, written in the 300s.

“Mix together a setier of passum, two handfuls of well-sifted cinders, a trickle of old wine and some cypress leaves. Pile all the olives in this mixture, saturate them with this paste in garnishing them with several layers, until you see it reach the edges of the containers.”

Passum is freshly extracted grape juice, so the lye in the ash-water interacting with this would make an interesting brew. There would be so much sugar going on in there that you could get both a lye cure and fermentation going at the same time. Freaky. Since then the Spanish have been masters of the lye cure. Most Spanish table olives are cured at least in part with lye, but their process is far different than that used in to make the hideous Lindsay olive. I am modifying a method I found in an agricultural book written in 1817.

Incidentally, other popular modern olives that use a lye cure include the French lucques, Italian cerignola and Spanish manzanilla.

First thing you need to know about curing olives with lye is that you must use fresh green olives. Not black ones, not half-ripe ones. The lye process softens the meat of the olive, so you want it as firm as possible. When you are picking your olives, watch out for olive fly. The larva of this nasty little bug burrows into an olive and eats it from within. Thankfully infested olives are easy to spot: They will ripen faster than healthy olives, and there is a tell-tale scar on the olive that looks like this:

A wormy olive.
Photo by Elise Bauer

Toss that olive. While the worm is not poisonous, I prefer my olives sans extra protein, thank you.

What sort of lye do you use? The traditional brand to use is the classic Red Devil Lye, which is an old brand of drain cleaner. But all the science I’ve seen says anything that is 100 percent sodium hydroxide works, so scan your drain cleaner well to make sure it is nothing but lye — Drano used to be this way, but apparently has additives now. Don’t use it. Buy “food grade” lye if you want to, but after much research, I can find no hard evidence that there is any difference between so-called “food grade” lye and non-food grade lye. I’ve used both.

Isn’t lye a deadly poison? Sorta. Sodium hydroxide is one of the nastiest bases we know of; a base is the opposite of an acid. On the PH scale, distilled water is the median, at 7. Your stomach acid’s PH is about 1 1/2 — enough to burn a hole through a rug. Lye’s PH is 13.

Bottom line: Raw, pure lye will burn the hell out of you, but it is not a systemic poison. That means that even if you eat an olive that still has a lot of lye in it — as I did — all you will taste is a nasty soapy flavor. If you eat a bunch of them, the alkaline PH in the olives will counteract your stomach acid and it might give you indigestion. That’s all, and that’s a worst-case scenario. That said, you need to be careful at that one moment you are moving raw, pure lye from the container to the crock you are curing into.

Raw green olives on a table.
Photo by Holly A. Heyser

LYE CURING STEP BY STEP

Follow these instructions and you will be fine:

  • Wear glasses if you have them. Wear long sleeves and pants and closed shoes. You will probably not get lye on you, but better to be safe.
  • Pour 1 gallon of cold — not tepid, not hot, but cold — water into a stoneware crock, a glass container, a stainless steel pot, or a food-grade plastic pail. Under no circumstances should you use aluminum, which will react with the lye and make your olives poisonous.
  • Using a measuring device that is not aluminum, add 3 tablespoons of lye to the water. Always add lye to water, not water to lye. A splash of unmixed lye can burn you. Stir well with a wooden spoon.

You’re done. You use cold water because the reaction between lye and water generates heat, and the hotter the lye-water solution, the softer the olives will become. Now that it is mixed, the lye solution can’t hurt you, so go ahead and add your olives.

Stir them in with that wooden spoon and put something over all the olives so they do not float. This is vital. Olives exposed to air while curing turn black. Don’t worry, they will absorb the water and sink in a few hours, but to start you need to submerge them.

Let this sit at room temperature for 12 hours. The alkaline solution will be seeping into the olives, breaking the bonds of the bitter oleuropein molecules, which then exit the olive and go into the water. After 12 hours, pour off the solution into the sink. It should be pretty dark in color.

Quickly resubmerge your olives in cold water. You want to minimize the exposure to air. You now have cured olives. I know, I know, a lot of recipes say to repeat the lye process another time — sometimes three more times — but that will destroy a lot of flavor; there are a ton of water-soluble flavor compounds in an olive that the lye solution washes away. Trust me. Your olives, unless they are gigantic, will not be overly bitter even after just a light, 12-hour lye soak.

Now you need to cleanse your olives. They will have a fair bit of lye solution in them now. Keep changing the water 2 to 4 times a day for 3 to 6 days, depending on the size of the olives. After 2 days, taste one: It should be a little soapy, but not too bitter. It’ll be bland, and a little soft. Once the water runs clear you should lose that soapy taste.

Time to brine. If you have large olives, make a brine of 3/4 cup salt to 1 gallon of water. And use good salt if you can. You will taste the difference. Kosher salt is OK, but ideally use a quality salt like Trapani, which is from Sicily. It’s not that expensive, but it is worlds better than regular salt.

Let the olives brine in this for 1 week. Keep them submerged, or you will get darkening. After a while they will sink. After 1 week, pour off the brine and make a new one, only this time, use 1 cup of salt per gallon.

Now you can play. The traditional Spanish cure would add some vinegar to the mix, as well as bay leaf and other spices. I’ve played with adding a touch of smoked salt, chiles, black pepper, coriander, mustard seed, garlic — think Mediterranean flavors.

But before you do this, taste your freshly brined olives. It will be a revelation. They will remain beautifully green, unlike brined olives. Salty, olive-y and very, very buttery. This is the Lay’s Potato Chips of olives. I dare you to eat just one.

Brine cured green olives.
Photo by Hank Shaw

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About Hank Shaw

Hey there. Welcome to Hunter Angler Gardener Cook, the internet’s largest source of recipes and know-how for wild foods. I am a chef, author, and yes, hunter, angler, gardener, forager and cook. Follow me on Instagram and on Facebook.

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139 Comments

  1. I live in Temecula,ca. and I have an acre of Olive trees, that I’ve just started picking and your method of curing olives, is almost exactly the way my great-grandmother, from Tecate, BC does, till this day @ the age of 90. Our nieghbors always look forward,to their jar of delious olives. Great site and great info.

  2. I was wondering how many pounds of olives you used in this recipe. I only have about 2 or 3 pounds, would I have to up the amounts? Thank you!

  3. Hank,

    I have an olive tree in my yard and have tried brine and dry curing in years past, but the results have been too bitter for my taste so this year I tried lye curing. I used 3 tablespoons lye granules per gallon and let it go 10 hours. After 3 changes of water the olives have no bitterness and have remained firm and bright. The only problem is that the skins are peeling off the olives! Did I use too strong a solution? Any suggestions for next time?

  4. Hi Hank
    Just picked about 10 kg of nice firm green olives and have put them into a light brine solution.
    I am into my second day. The olives are still nice and green.
    I have just read your article
    Can I do the lye cure now? Will there be any reaction with the salt?
    Will wash them well before putting into the lye mixture

    Thanks for all the comments
    George

  5. Lye (sodium hydroxide or NaOH) won’t hurt you when handling small ammounts such as the 500gram tubs of drain cleaner. If you fell in to an idustrial sized vat of the stuff you may have some problems though.

    Some people with very sensitive skin may experience dermititis from handling it without gloves, but it’s not common. I’ve often clasped a hand full of it without gloves to throw down a drain or what not.

    As the author already said, do not use aluminium implements when preparing food with NaOH as the NaOH will disolve the aluminium and make it soluable in water. It’s not the NaOH that will poison you, but the aluminium.

    Also, never ever mix NaOH (or acids) with other house hold cleaners as it can change the chemical structure of the cleaning acid and make it toxic. This is probably where this relatively harmless chemical gets its bad rep from.

    Cheers,
    Stuart

  6. Great Site –

    I followed your recipe and olives came out fantastic – thanks!

    question ?

    I wore gloves and long sleeves the whole 9 and was totally freaked out using this stuff … I will continue to do so however you mentioned

    After the lye is mixed into the water – it cant really hurt you …

    Can you explain that a bit further ?

    Many thanks for all your great works !!!

  7. I would like to know where to get lye for this process. I have not gotten into it because I have heard it is hard to obtain lye.

  8. Thanks for your site. How about adding a little about checking for lye penetration by cutting into a couple of olives now and then?

  9. Greg: Yep, you assume correctly. If you want a vinegary thing going on, start with 1/2 cup and go from there. You can always add more, right?

  10. Hank,
    When I pour off the first salt solution I assume the second mix of salt and water is what I will put them in the jar with. My big question is if I use the 1 cup of salt to 1 gal of water how much vinegar would you put in the waterif you enjoyed the flavor of vinegar somewhat? 1 cup? I don’t want to overpower and this is my maiden voyage. Thanks

  11. Thanks Hank

    You can come to my house to harvest anytime. I have 18 70 year old olive trees on my property. I am currently finishing up my second 6 pounds of lye treatment greens. Shortly, we will be harvesting the dark olives to salt cure.

    Thanks for your blog!
    Brian

  12. Hi Hank,
    I just lye cured some olives for the first time using your method. My batch was kind of large, so it took a little longer than what you said. The bitterness is now gone and they are sublime!!! Canning time – what proportion of vinegar – water – salt should I use? I would like to do the traditional Spanish style (since the olives were picked from trees on a Spanish Mission property in California)

  13. Hi All: Poor math skills led me to over-lye my olives. I rinsed in water for 5 days and spot-tasted several. They tasted fine. But now that I have started my salt baths and eaten whole ones, I’m worried that they actually taste like lye. There’s no bitterness and the olives are nice and soft, but even as I write, I have this weird sensation on my tongue. From the lye? Should I stop the salt baths and return to water? The water was the faintest green when I switched from water to salt. Thanks!

  14. Changed my brine to a 1 cup per gallon of water today. Yep just like Lays…..couldn’t just sample ONE!! They are simply delicious. Just in time for Thanksgiving and holiday “from the kitchen” gifts. Should probably start another batch since the trees are still loaded and don’t look too ripe. Kathy

  15. Hank,

    I grew up surrounded by old Sicilians, all of whom cured olives of one type or another. Unfortunately I never paid attention to how they cured them because their olive jars were always ‘around’. Now the old ones are gone, and with them their recipes for curing olives. My son, an avid hunter, fisherman and cook, recommended your website to me. A little over four years ago, I planted a mini-olive orchard of 89 trees. This is the first year they produced a small but viable crop. I used your lye recipe for curing about five pounds of olives. Although it took 14 days to leach all of the lye out, and another 14 days to infuse them with pink Himalayan salt, the result is simply fabulous! You are right–they are the Lay’s Potato Chips of olives–you can’t eat just one!

    Sincerely, Your New Devotee,

    Frank Balestrieri