Olives, Water-Cured, Kalamata Style

Ripe black fruit, two knife cuts, ten days of water changes, and then a month sitting in a salt-and-red-wine-vinegar brine under a slick of olive oil. This is the water cure that produces the olive most people actually want. The diagnostic detail: the oil cap is not a garnish — a quarter to three-eighths of an inch of olive oil poured on top is what lets this one keep at room temperature when the cracked green version has to live in the fridge.

Ingredients

THE OLIVES

• 10 lb mature olives, fully coloured dark red to purplish black, firm, picked before the first frost
• Water to cover, changed daily

FINISH BRINE (for about 10 lb of olives)

• 1 gallon cool water
• 1 lb pickling salt (1 1/2 cups)
• 1 quart red wine vinegar (4 cups)

TO SEAL

• Olive oil, enough for a 1/4 to 3/8 inch layer on top

Directions

Key ingredients

Salt · Olive Oil

1. Step 1 - Use ripe fruit, and not Sevillano. Dark red to purplish black, firm, harvested before the first frost. Any variety will do except Sevillano, which goes too soft for this method — Manzanillo, Mission and Kalamata are the usual choices. Sort by size and throw out anything bruised.
2. Step 2 - Make two lengthwise cuts in each olive, about 1/8 inch deep. Not a smack with a mallet — that is the other water cure. Two clean knife cuts into the flesh, which is enough to let the water in without wrecking the fruit.
3. Step 3 - Cover with cool water and weight them under. A plate, or a sealed bag of water, on top. Lid loose. Anything floating above the surface oxidises and softens.
4. Step 4 - Change the water daily for 8 to 10 days. Drain, rinse, refill, same time each day.
5. ⚠ Step 4a - If you want them milder, go on to 20 days, but watch them. UC’s own warning is worth quoting: over-soaking gives you soft olives with a washed-out taste. This is the one cure where more patience makes the product worse.
6. Step 5 - Make the finish brine. 1 lb (1 1/2 cups) pickling salt dissolved in 1 gallon of cool water, then 1 quart (4 cups) of red wine vinegar stirred in. That is enough for about 10 lb of fruit. Note the vinegar quantity — it is four times what the cracked green cure uses, and it is red rather than white.
7. Step 6 - Pack, then float the oil on top. Drain the olives, cover with the brine, and pour 1/4 to 3/8 inch of olive oil over the surface. Close the lid firmly.
8. Step 7 - A month at 60 to 80 °F. They marinate in the vinegar-salt solution and the flavour comes together. Room temperature is correct here.
9. Keeps about a year in the finish brine, in a cool dark place or refrigerated, as long as the container stays airtight.

Notes

Where the numbers come from. Olives: Safe Methods for Home Pickling, UC ANR Publication 8267 (Yada and Harris, UC Davis, 2007), read in full. An earlier version of this recipe was built from a county extension digest of that publication and has been corrected against the original.

⭐ Why this recipe exists separately from Olives, Water-Cured (Green). Because 8267 has two water cures and the digest I first worked from had merged them. This one is the Kalamata style: ripe black fruit, knife cuts, red wine vinegar, an oil cap, room temperature. The other is the Mediterranean cracked style: green fruit, a mallet, white wine vinegar, and the refrigerator. Mixing the halves gives you something nobody tested, which is exactly what my first draft did.

⭐ The oil cap is the mechanism, not the decoration. It is a physical barrier over the brine surface, which is where mould and surface yeasts start. That is what buys this version its year in a cupboard.

⚠ This is still not a canned, shelf-stable food. Water-cured olives of either style are not on 8267’s pressure-canning list — see Olives, Lye-Cured (Reference) for the awkward reason only one cure is.

🔴 Not Sevillano. 8267 names it as the variety that softens on this method. If a California grower sells you a box labelled just “olives”, ask, because Sevillano is one of the commonest home-curing varieties shipped.

Softening in storage is caused by pectin-degrading enzymes from surface moulds and bacteria, and it can ruin a batch within two weeks. UC’s answer is a storage brine of at least 10% salt — 13 ounces (1 1/4 cups) of pickling salt per gallon of water. That is the same 10% figure Italy’s ISS gives for home-preserved olives, reached from a completely different direction.