Olives

The olive gets its own page because it is the only thing in this section that is genuinely inedible before you process it, and because the processing splits four ways — two of which belong here and two of which belong in Fermentation.

It is also where I have a story I like, from a duplex in Kuwait.

Raw olives are not food

Bite a raw olive off a tree and you will not do it twice. The bitterness is oleuropein, a phenolic compound that is present in serious quantity in every olive on earth, and it is not a matter of taste or ripeness. An olive must be debittered. This is not a preference, it is a requirement, and it is the reason olive curing is a craft rather than a recipe.

Every method below is, at bottom, a different way of getting the oleuropein out.

The four methods

Method	How long	What it does	Where it belongs
Lye	8–12 hours, then washed	Chemically breaks the oleuropein bonds	This section
Water	About a month, changing water	Leaches it out slowly	This section
Brine	Many months	Leaches it and ferments	Fermentation
Dry salt	Weeks	Draws it out with the moisture	Borderline — mostly here

Lye

The commercial method and the fastest by an enormous margin. A sodium hydroxide solution breaks the chemical bonds holding oleuropein together, which then leaves the fruit into the liquid. 8 to 12 hours, then the olives are washed thoroughly — up to three times — until no trace of lye remains, and then brined for keeping.

This is how the smooth, mild, uniform “California black ripe” olive in a can is made. It works, it is fast, and it produces a consistent product.

⚠ Several extension services steer home cooks away from it, and I think they are right. Lye is genuinely caustic — it will burn skin and eyes and it must not touch aluminium — and the margin for error on the washing step is the difference between an olive and a chemical burn. It is not that it cannot be done at home. It is that the payoff is speed, and speed is the thing a home cook needs least.

Water curing

About a month, changing the water daily or every couple of days. Slow, tedious, entirely safe, and it keeps more of the olive’s own flavour than lye does because you are not chemically stripping it. This is the method I would tell anybody to start with.

Brine curing — which is a ferment

Olives in a salt brine for many months, during which lactic-acid bacteria go to work and the oleuropein leaches out slowly. The Greek and Sicilian natural-brine olives are genuine lacto-ferments — the same craft as everything in the other section, applied to a fruit.

Which is why they taste the way they do. A brine-cured Kalamata has the complicated sour depth of a ferment; a lye-cured canned black olive does not, and cannot, because nothing lived in it.

Safety: as with any ferment, the brine must fall below pH 4.6 to exclude C. botulinum, and the olives must stay under the brine. This is the point at which the safety page applies with full force.

Dry salt curing

Ripe black olives packed in layers of salt, which draws out both moisture and bitterness. Weeks rather than months. The result is the wrinkled, intense, slightly leathery oil-cured olive — the Moroccan-style one. Often finished with olive oil and herbs afterwards, which is where the “oil cured” name comes from, though the oil is a finish and not the cure.

⚠ Home-cured olives have a real safety history

Worth stating plainly, because olives feel like a Mediterranean-sunshine food and not like a hazard.

Home-cured olives have a documented botulism history. The risk factors are exactly what you would predict from the rest of this section: low acid, long anaerobic storage, and sometimes a layer of oil on top excluding air — the same shape as garlic in oil.

The controls:

• Acidify. Brine-cured olives need to come below pH 4.6, and a home curer should be checking that with strips or a meter, not guessing.
• Keep them submerged.
• Refrigerate anything you are not certain about, and anything finished in oil.
• Do not can them at home without a tested process. Olives are low-acid; a boiling-water bath does not get there.

⭐ Kuwait, and Mary’s lemon olives

Around 2009 I was living in Kuwait, in Yusef’s duplex, and Mary — who was from the Philippines — made olives with lemon. They were terrific and I have thought about them on and off ever since.

Now that I understand the chemistry, I can tell you something about what she must have been doing, and I want to be careful to separate what I know from what I have worked out.

What I know: she made olives, they were finished with lemon, they were very good.

What the chemistry says: lemon juice alone cannot debitter an olive. Citric acid does not break oleuropein down the way lye does, and it does not leach it out the way weeks of water or months of brine do. A raw olive covered in lemon juice stays a bitter olive.

So she must have cured them first — water or brine — and used the lemon as a finish: the flavouring stage after the debittering was already done. That is a completely standard and very Mediterranean-and-Levantine way to handle olives, lemon and often garlic and chili going in at the end.

I am setting that out as a reconstruction, not a memory. I did not watch her do the first part, and forty-year-old — well, fifteen-year-old — recollections of somebody else’s cooking are exactly the thing this section keeps catching itself getting wrong. But the chemistry only permits one answer, and it is a nice case of being able to recover a method you never saw.

If you want to try it

Get raw olives in season — roughly September to November. They are not a year-round product and this catches people out. Farmers’ markets in olive-growing regions, Middle Eastern and Mediterranean grocers, or direct from a grower.

Then:

1. Sort by ripeness. Green and black cure at different rates; do not mix them in one jar.
2. Slit or crack each olive if water curing — it dramatically speeds the leaching.
3. Water cure for a month, changing water daily, tasting from week two.
4. When the bitterness is gone, move to a holding brine — around 5–8% salt — and season with lemon, garlic, chili, oregano, bay, whatever you like.
5. Keep them cold, keep them submerged, and check the pH if you brine-cured.

It takes a month and almost all of it is waiting. It is the least demanding project in this section and one of the most satisfying, because you start with something you genuinely cannot eat.