Brine-cured olives
A raw olive straight from the tree is inedible — it holds oleuropein, a glycoside so bitter it puckers the mouth. The whole curing process is essentially removing that bitterness, followed by lactic fermentation in brine. It takes patience: at least a week of daily water changes, a month in brine and two weeks in the final brine. Nothing speeds it up except lye, which is not worth using at home.
Your own work in that: 30 min.
- Slitting the olives 40 min
- Debittering in water 10080 min
- Fermenting in brine 43200 min
- Final brine 30 min
- Maturing in the final brine 20160 min
Step by step
0 / 8 doneSort for firm, undamaged olives
Sort through and discard any that are wrinkled, punctured or spotted. Damaged fruit spoils in brine and infects the whole batch. Green gives firm, bitter olives; black gives soft, mild ones.
Ingredients: 2000 g raw olives · 3000 ml water
Slit each olive to the stone
Cut each olive lengthways in two places, right down to the stone. The cuts open a path for the water — unslit olives need three months instead of a week and stay bitter inside anyway.
Ingredients: 2000 g raw olives · 3000 ml water
Two cuts to the stone — without them water cannot enter.Cover with water, changed daily
Cover the olives with water, weigh them down so none stands proud, and change the water daily for 7–10 days. The water runs brown — that is oleuropein leaching out. Keep changing until it stays nearly clear.
Ingredients: 2000 g raw olives · 3000 ml water
Brown water is the bitterness — change it until nearly clear.Test the bitterness by tasting
After a week, bite into one olive. It should still be clearly bitter but edible. If it puckers your mouth, soak for more days — in brine the bitterness fades only slowly.
Ingredients: 2000 g raw olives · 3000 ml water
Make a ten per cent brine
Dissolve 200 g of salt in 2 litres of water — a 10 per cent solution. Some of the salt passes into the olives, so the brine gradually weakens; at that strength lactic bacteria work while most spoilage organisms do not. Cool it completely; hot brine softens the olives and kills the lactic bacteria present on the fruit.
Ingredients: 290 g non-iodised salt · 3500 ml water · 100 ml wine vinegar
Ferment a month under a weight
Pack the olives into a large jar or crock, pour over the brine and weigh them down so all stay submerged. Cover loosely and keep 30 days at room temperature, out of the sun. The brine clouds and a white sediment appears — the normal sign of lactic fermentation.
Ingredients: 290 g non-iodised salt · 3500 ml water · 100 ml wine vinegar
Skim any film that forms
Check every few days and skim off any white film. That is kahm yeast — harmless but it spoils the flavour. Coloured or fuzzy mould, by contrast, means the batch must be discarded.
Ingredients: 290 g non-iodised salt · 3500 ml water · 100 ml wine vinegar
Repack in fresh brine with herbs
After a month drain the olives and divide them between two jars with the garlic, lemon and herbs. Cover with fresh 6 per cent brine: 90 g of salt dissolved in 1.5 litres of water, plus the vinegar, and seal the surface with a layer of oil. Close and keep in the fridge. Wait another two weeks before tasting seriously.
Ingredients: 2 pcs lemons · 2 tbsp fennel · 4 pcs bay leaves · 6 cloves garlic · 2 tbsp oregano · 2 pcs dried chillies · 100 ml olive oil
Fresh herbed brine and a layer of oil sealing the top.
Before you start
Lye curing is faster but not for home
Industry debitters olives with sodium hydroxide in a matter of hours. At home that means carefully measuring caustic lye, gloves, eye protection and days of rinsing, and an error means caustic olives. The water method takes longer but is safe.
Green or black
Green olives are unripe: firm, bitter and slower to debitter. Black are ripe, soft and sweeter but break up when slit — cut them shallower or prick them with a fork rather than using a knife.
Up to a year in the fridge
Keep the finished olives in the fridge for up to a year, always fully submerged in brine under a layer of oil. Take them out with a clean spoon, never fingers — a single contamination can spoil the whole jar.