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A Recipe for Curing Green Olives

Olives are fantastic in many forms, but are essentially inedible unless processed. Processing and curing of olives dates back to the dawn of man. Varied and meticulous are the recipes that have evolved; they have almost religious implications. Here we outline a simplest, convenient recipe, based on the ferment that occurs. The intent is to produce a mild green olive, with a minimum of attention and effort.

A few traditional recipes use raw olives as spices, but most olives not used for oil are highly processed. The processing can be as simple as storing the olives in salt or bruising the fruit and washing for months in sea water or fresh water, but most require a deal of persistence and waste large quantities of water. Commercial recipes are most detailed and scientific; they grade the olives and measure the chemical constitution, as the ferment develops.

And there is a ferment, that goes through many stages. Bill Mollison, in his book, A Permaculture Book of Ferment and Human Nutrition, suggests that the fermentation of olives involves at least 5 different bacterium species. Around 6-10 days the bacteria are mostly lactic acid bacteria. Later, at 12-15 days, yeasts develop with the lactic acids. After the ferment, the olives can be preserved by heating and bottling, submersion in brine or olive oil.

Lye, wood ash or quick lime plays a part in the removal of the intensely bitter raw olive flavour, the glucosides that contribute to their inedibility. Rinsing is invariably a part of the process, to remove the lye and the bitterness. Salt and vinegar and olive oil can play major roles in curing and preservation. Olives have been prepared traditionally using months of rinsing in pure water and/ or brine, with or without vinegar, canning or the use of olive oil. My home in Western Australia is not next to the sea shore and adding salt to our already saline waters is unpalatable to me. Also, we have a dearth of water, so I am reluctant to wash the olives any more than necessary.

Importantly, I want to enjoy the ‘harvesting’ and ‘brewing’ of my olives. I need a convenient and relaxed recipe. The following recipe has been used with many varieties of olives, including ‘ferals’ that grow along the road. Three batches in the last 5 years have included some testing that showed that:

  • the ‘bitterness’ is removed totally after soaking in a 20g/litre solution of lye for more then 8 days.
  • the ‘bitterness’ is tolerable after 5 days of soaking.
  • the ‘softness’ is increased with long soaks in Lye.

Otherwise, it may be that the presence of salt with the lye will diminish the softening of the olives. It may be unnecessary to ‘fully can’ the olives, but mine have kept without degradation for 4 or more years. I don’t like the idea of scraping off the scum when you want to eat them, say 5-10 years later. They might have a better flavour, but I would just throw them out.

For a simplest batch, I suggest:

Required:

  • 9 litres of olives, right off the tree. Don’t worry about leaves and rubbish or the size of the olives, but avoid sticks and pebbles. These are green olives. It is best if a few of them are starting to ‘blush’ but totally green olives, as appear in early autumn (March-April in Perth; I presume September-October in the Northern hemisphere) are satisfactory. I don’t throw any away; the small and ‘feral’ ones may have almost no seed and are delicious; the small ones that haven’t developed or have dried have almost no flesh, but still have a good flavour.
  • 2 10 litre buckets. Polyethylene, polypropylene are fine. Metal buckets should be avoided.
  • 2 convex dinner plates (glass is best) that just sit inside, and reasonably seal, the top of the buckets
  • 80 grams of lye (NaOH). This is often used to clean drains. Take care that it isn’t too contaminated. Wood ash will do, except that a longer time will be required and the process becomes ill-defined.
  • 200 grams of salt (NaCl). May be sea-salt or ‘bush salt’
  • a source of fresh water (hose)
  • a wet area (porch or laundry)
  • some plastic water-tight gloves
  • a clean stick, perhaps a metre long

Procedure:

Fill one bucket with water. Pour in the olives, evenly, and so as not to lose them. The excess water and leaves and rubbish should be somewhat removed in the overflow. Brush any other debris off the surface with the plate. Using the plate as a stay to hold the olives, pore the water into the other bucket; this should be about 4 litres. Add the 80 grams of lye to the water in the bucket; slowly, so as not to cause boiling; the lye can have a violent reaction with the water. Avoid contact with the lye or the water containing the lye. Note that it doesn’t matter if some colour or dirt remains in the bucket. Stir with a clean stick; it is best to use water-tight gloves to cover your hands.

Add the olives to the lye solution; let them tumble from the bucket; the bucket should fill to the top with the olives and the lye solution. Yet, there should be a layer without olives on the surface. Cover the top of the liquid with the plate, pushing the plate down and on to the olives; this should leave some liquid on the top of the plate, to insure that the plate stays in place. This should minimise the exposure to air and keep the olives from turning brown.

Leave the bucket in the shade and perhaps covered to keep bugs, flies and animals from polluting the ‘brew’ with their bodies (a cloth will do – a sealed environment is not required). The ferment begins then, give it 5-8 hours. 7 hours is recommended and, if you sleep 7 hours each night; one night is an easily measurable time for the lye treatment. This is critical; 5 hours leaves a very bitter and hard olive; 8 hours leaves an olive without any real flavour that may be mushy. (Further batches from various trees has revealed that some olives can only be treated with lye about 3 hrs; other olives require more than 18 hrs. These are known varieties from backyards; the ferels so far haven’t shown such variability.)

After the 7 hours, pour the lye down the drain, while holding the plate in your gloved hands to keep back the olives. If you feel any stinging in your hands, wash your hands and the gloves immediately; lye is not only a good drain cleaner but it also is a good skin remover!

Now, fill the other bucket with fresh water. Pour the olives, tumbly-tumbly, into the bucket of fresh water. Let the water overflow, cleaning the olives and removing a part of the lye. Watch the bottom of the bucket, as the olives go into the water. Near the end, any pebbles and other rubbish, and even, perhaps, a few rummy olives can be discarded.

Cover the olives with the plate again, pushing the plate down onto the olives. There should be no real concern about the lye now, but you still may want to use gloves or the stick. Leave for one whole day covered, in the shade, and isolated.

Tip out the ‘fresh’ water (it will be brown, as the lye was and all rinses will be). Fill the empty (and clean-rinsed) bucket with fresh water. Pour the olives into the fresh water, cover with both the plate and the cloth.

Repeat this for 7 days, a whole week. This is not critical but olives soaked for only 3 days aren’t so nice.

Then, when you tip out the final rinse, and leave the ‘dry’ olives, tip the water into the ‘clean’ bucket. Again, this should be about 4 litres. Add the 200 grams of salt to the water; stir until it is dissolved. Add the olives. Cover the olives with the plate and cloth. Let set for at least 4 days, perhaps a week. This time is not critical and, in fact, this salt concentration (50 grams per litre) is supposed to be sufficient for indefinite preservation of the olives.

I prefer the 4 day period because the ferment does continue and I like the product. After 4 days, I pour off the brine (salty water) into the second bucket, add 0.4 litres of Vinegar (apple cider), and stir it up. This makes the preserving liquor.

The ‘dry’ olives are now packed into jars and the liquor is added. The caps are put on loosely and the jars brought to a boil for 20 minutes, in a canning pot. Removal with tongs and tightening the top finished the sealing. Do check, however, to see that there is a proper ‘dimple’ in the top and that the seal is complete. If not, one should keep them in the fridge and eat them soon.

The vinegar and heating should totally stop the ferment and preserve the olives for years. Do not presume, however, that the olives will be vinegary when the jar is opened. Indeed, much of the vinegar is probably lost in the boiling. I prefer to open the olives and add about 10% vinegar (apple cider, of course) to the mix before eating them. They are also a bit salty, so you may want to exchange the brine for fresh water before eating. It is also a good idea to wait two-three days after altering the liquid, to allow the flavours to seep into/out of the olives.

For real bliss, add some grated or crushed garlic or onions or chillies; bulb fennel, ginger or red capsicum, perhaps some spices like dill, oregano, black peppercorns, coriander seeds or rosemary. One combination is garlic, basil and lemon juice. Orange or lemon peel may be added to the liquid. An alternative is to use some commercial spice mixes or some old ‘pickling water’ from commercial gherkins or beetroot.

Please take this recipe as it is, for your pleasure and good health. I can not vouch for how good it may be for you and I am sure there are many ‘better’ and many ‘worse’ recipes. this one is only intended to be easy, convenient, and ethical – but I can not stay away from the results.

Bill Scott
23 December 2000