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 Pittsburgh, Pa so getting raw olives is difficult. This year I found some nice big green ones. I had used the lye process years ago. But, I forgot how to do it. But, I found a great paper on all the different curing processes that you all might want to read anrcatalog.ucdavis.edu/pdf/8267.pdf

  2. As a kid growing up my grandparents and parents would make home lye cured olives every year. I remember walking by the crock and taking a few (more like a handful)of the wonderful homemade olives. So this year I picked olives off our 100 year old olive trees, same ones my ancestors picked from, got “food” quality lye from Ace Hardware and tried my hand at making them. I divided my harvest into three containers, and started the process. Today is their second day in the first salt (used canning salt) brine and they are delicious. I will admit that a few of the larger olives are still a bit bitter but I’m sure they will get better as they remain in the brine. I plan on making a heavy salt brine and putting them in jars for holiday gifting. I will include directions to pour off the heavy salt brine and replace with fresh water and put them in the refrigerator. I’m so paranoid about botulism I feel that is the best way to go. Kathy

  3. Instead of lye, which isn’t readily available in its pure form in the stores near me, I tried potassium carbonate which is readily available in Asian grocery stores for noodle making. Check in the vinegar and sauce section. While not as alkaline as lye, at full bottle strength, it still cured the olives faster than brine alone.

  4. Hi Hank,
    we have 5 olive trees in our yard and have made these olives only once and they were great so this year we decided to make a lot more (10 buckets). The olives were huge and it took about 36 hours of lye solution to turn the core completely green(as opposed to white). We then completed the rinsing process and put them in the brine solution and brought some into the house in the refrigerator after 24 hrs. These olives are delicious…however, the olives outside in the brine solution are turning wrinkly, soft and dark. They have been kept in the shade, covered and temp here is about 45-50 degrees at night and between 70-75 during day. We’ve never had this problem and not sure what is happening. Any ideas???? Your help would be much appreciated!
    Thanks, Sharon

  5. Liz: There is plenty of salt in these olives, so it should be fine. I keep them in the fridge in a jar of brine. I find that they last this way for nearly a year. After that they, get kinda skanky. You can store them in the pantry, but they will rot after only about 3 months.

  6. Hi Hank,

    How much concern do you have about botulism when you cure olives? Do you keep them in a covered, but not air-tight container? Have you ever thrown out any of your olives, or seen any kind of film develop on the top of the brine/container?

    Thank you for your guidance!!

  7. Thanks Hank, so I can eat them right out of the second brine right away, and leave them in that brine in the fridge, correct?

  8. Dee: Yep, I did mention in the instructions that if you have really large olives you will need to soak in lye longer. Glad they came out well!

    And once they are in the stronger brine, they are ready to eat. And I don’t “process” them at all. I add whatever flavors I want — bay leaves, mustard seed, chiles — and let them sit in the fridge. I would NOT can them because the heat will wreck the olives.

  9. Hank, I love your website… I was given a 5 gallon bucket of the largest olives I have ever seen, I did the lye solution for 12 hours then soaked in water changing twice a day, after a week they were still too bitter and it only had a luner eclipse of penitration, so I lyed them for another 12 hours and soaked and rinsed for another week, they are perfect!

    Now I am starting the brine solution. On your recipt you have me brine for 1 week then change out to a stronger brine…

    How long do you do the second brine before you process? 1 week? or start processing that day? Do you use the brine in processing or rinse them, then process?

    Thanks again, this is a wonderful sight and my husband does a lot of hunting and we do a lot of gardening and I enjoy grinding whole grains and beans and making my own breads from them. You sight is a wonderful addition to my library!

  10. As for the comment tha noted 12 hours of lye may not have been enough, my test was after the 1st 12 hours, I rinsed and cut into a couple of olives – if you see white near the pit, they need more time – if it was green/yellow all the way to the pit, they were good.

    It turned out the small ones were good, but the larger ones needed more time, so I re-did the lye for about 9 hours and that seemed adequate for my batch.

  11. One week in brine and they taste great as is. My wife and daughter ate the dozen or so that didn’t make the jars.

    I was at a loss for flavorings and process as well. With jalapenos and red peppers, I added chopped fresh garlic, a tablespoon of olive oil to the jar and microwaved for 1 minute – I let it cool then added the olives and brine. I figured that would ‘release more flavor”.

    Other combos were fennel with lemon slice, raw garlic with bay and oregano, and just chopped garlic heated with olive oil. Several jars of just plain brine.

    One week in the fridge and they should be ready.

  12. Hank,

    I cured my first 20lbs of green olives with lye last month. Unfortunately, after the 12 hours in the lye cure, I started the rinse/soak phase without making sure they were debittered enough. After almost two weeks of soak/rinse, I went ahead and brined them. After two weeks in the brine, I like the brine flavor, but they are still way too bitter for us. I gave most of them to my pigs and now have just 3 quart jars in the fridge.

    So my question is….   Will they continue to lose bitterness in the brine if I refresh it or is this the final product? Also, once you’ve brined them, it’s too late to go back and re-lye, right?

    Thanks so much!

    Sarah

    Chico, CA

  13. To those who are troubled with the lye solution try this. Go to the local pharmacy and have them mix up a solution of phenolphthalein. It usually comes in a little eyedropper bottle. A drop of this on a lye saturated olive will turn a majenta pink color and if there is no color there is no lye. It will show even trace amounts. I do between 100 to 200 gallons every year and have a 30 gallon batch going now. Evidence that they are good is the line of friends I get every year with containers in tow.

  14. We received a wonderful jar of green olives cured in lye from a co-worker and they are delicious. Is it possible to get the “runs” from eating too many? thanks.

  15. Sarah: What probably happened is that Chaffin sent you olives that were *very* unripe, so the 12-hour lye treatment was not enough. But fear not, they will get less bitter over time in the brine.

    This process is how the Spanish make many of their olives: A quick lye cure followed by a long brine. It’s a hybrid of the lye/brine process. It might take a while for all the bitterness to go away, but it will eventually.

  16. Question… I lye cured my green olives for 12 hours and then brined them after the rinse period. They had a week of rinsing twice daily in water and then have had a week in brine. They are still too bitter for the family. It’s much too late to re-lye them, right?

    I got the olives from Chaffin orchards in Oroville, so they were good quality and medium size.

    Thanks!

    Sarah

  17. Hey Hank,

    Just wondering, I have lime (calcium hydroxide i think) that I use for treating corn, can it be used to cure olives with this method instead of lye?

  18. While I appreciate your open ended herb/spice flavoring suggestions, would you mind providing specific herb/spice combo recommendations, with quantities. Olive curing time only comes once a year, and I have ruined olives w/ spice/herb combos I haven’t liked. Thank you!

  19. No, I didn’t do them all in one batch. I used two 3 gal crocks and used three tablespoons per each gallon of water to cover. Since it took two more days to get my query through the moderator on your site, I went ahead and tried my own method to try and save them. It may not work, but they are inedible as is. I put them back into a lye soak, weaker, and for less time, and will try the whole thing again. If I have to throw them out I can hopefully get more and use my old tried and e method. I guess I should have stuck with that, but thought yours would be worth trying.