Brined - Mediterranean

Black olives

Name: Black olives
Cuisine: Mediterranean

The ripe-olive process, which adds a brine soak before the lye because the compound being removed sits deeper in a ripe fruit. It also carries a wash-water temperature with a consequence attached, which is unusual for this bulletin and worth reading twice.

5 steps, every one quoted from FAO Bulletin 134 6.2.5. The step labels are this site's; the sentences under them are not.

This recipe uses sodium hydroxide

Lye is caustic. It burns skin and eyes on contact and is not a food ingredient in the way salt is. This site publishes the process because the source publishes it and because an olive genuinely cannot ferment until the compound lye removes is gone. It is not telling you to do this, and it is not a set of handling instructions. If you have not worked with a caustic solution before, read the safety page first and take the sourcing of protective equipment and a neutralising rinse as your own responsibility.

Salt, at a batch you might actually make

2 to 5 % salt in water, of the weight of the finished brine.

Water	Salt at 2%	Salt at 5%
1 kg	20 g	53 g
2 kg	41 g	105 g
5 kg	102 g	263 g

The arithmetic, at 2 kg

Percent by weight of the finished brine.
salt / (salt + water) = percent / 100
salt = water x percent / (100 - percent)
     = 2.000 kg x 2.00% / (100 - 2)
     = 40.8 g

Finished brine: 2.041 kg, of which 2.00% is salt.

This is a percentage by weight of the finished brine, which is what a salinity meter reads and is not the same as grams per 100 mL of water. The calculator gives both.

Every number the source states

Fermentation brine: 2 to 5% salt in water
Softening brine before lye: 5 to 7% salt in water
Packing brine: 3 to 5% salt in water
Fermentation period: two to six weeks
Lye solution: 0.7 to 2.0% sodium hydroxide

Substrate

Olive

Region

Mediterranean

Method

Numbered for your place in the list. Every sentence below is the source's own, verified against the page it came from when this table was last built from the sources.

Soften first
When ripe olives are used, they are placed in a 5 to 7% brine solution to soften the outer tissue before lye is added.
Lye treatment
After soaking in brine, the lye solution (0.7 to 2.0%) is added and, after soaking, the olives are washed clean.
Brine and ferment
They are then packed in barrels with a 2 to 5% brine solution and allowed to undergo fermentation for two to six weeks, depending on the external temperature.
Leave these ones open
Unlike immature olives, the ripe one are exposed to air during fermentation.
Pack
The finished product is packed in a 3 to 5% brine solution and then sterilised.

What else the source says

Why the air: This is to oxidise the polyphenols in the tissue to a black colour, which is dependent upon oxygen and the small amounts of sodium hydroxide which are left on the olives.
The wash water has a floor: If the wash water used for removing the lye is below 60°C, many species of undesirable bacteria can survive which result in a low quality product.

Before you make this

This site is a reference and not a food safety authority. It reports what named sources published and does not certify that any preparation is safe. The safety page sets out what the sources themselves say about acidity, about surface growth and about when to throw something away, and equipment lists the instruments the numbers above cannot be checked without.

The full record for this pickle, including every source consulted and the ones that disagree, is on its tradition page.

Other brined recipes

Method and asides from FAO 134 Battcock, M. and Azam-Ali, S. (1998) Fermented fruits and vegetables: A global perspective. FAO Agricultural Services Bulletin No. 134. Food and Agriculture Organization of the United Nations, Rome. Numbers from the same source, extracted separately and listed on methodology.