Salt (rock salt or other NON IODISED NON ANTI-CAKING AGENT salt.)
Herbs and spices if desired for bottling.
Crocks, tubs, vessels, jars, bottles, etc.
Olives are easy enough to deal with. You pick them, clean them of leaves and stems, wash them (sometimes) and pickle them in brine or pack them in salt. Different olives are better for different processing. And it doesn't get any simpler than that.
Olives are ready to process when they're plump but still green. Leaving them on the tree until they're black is recommended for making oil, but green gives the best flavour to pickled/preserved olives. Small black olives are best salt pickled. I won't go into the varieties, because what you do will depend on what olives you have to hand, and what you want to do with them.
The best fancy brine preserved / pickled olives are picked a very young very bright green, and processed as quickly as possible. The trade-off is that they aren't full grown so the harvest makes a smaller amount.
Green but far more ripe olives (just before beginning to show a turn of colour to red/black patches) are the most usually brined and bottled, and black ripe olives can both be brined or crushed for olive oil.
Black olives are generally softer to begin with and don't process very crisp, but then again some varieties are grown specifically to be firm and crunchy when black. Knowing what to do with each variety is part of the fun... %)
Green (And Black) Fancy OlivesMake a brine that will just barely float an older egg. Let it cool. Meanwhile, sort your olives. I use an old wire rack out of a refrigerator angled over a tub. Small olives fall through, larger ones roll into the next tub. The large ones are your fancy olives and make the best. Also, large fancy take a little longer to process than brining the smaller ones because the polyphenols leach out at a fixed sort of rate, and the thicker a layer of fruit they have to leach out of, the longer it'll take.
So - have a clean tub, bucket, or crock that'll hold all the olives of the size you're doing, wash the olives, and in the case of large fancy green, make two slits on opposite sides. You don't have to slit them, but I've tasted them both ways and I prefer the slit version, salt seems to penetrate faster and deeper this way, and doesn't affect texture.
I've also heard and seen to crack the olives with a bottle or rolling pin, but it seems a waste to me to save the fruit from bruising from the tree to the processing bench, and then bruise them... I can slit 10kg of olives in about the same time as it takes to smack them around with the bottle, and results seem to me to be better when a bit of care is taken.
Also, note that there's a difference between washing the olives or just rinsing them - the former removes a lot of beneficial yeasts and organisms but may be necessary if the crop has been exposed to dirt and contaminants, the latter is good for a crop that you've picked yourself and kept clean in transit. Just a quick rinse is probably better.
(If I can pick my own olives I'm a happy bloke, by the way. I've used step ladders and apple picking baskets, and also reusable shopping bags, as long as you have the receptacle right in front of your chest when picking so that the olives don't have far to fall, they'll stay un-bruised and beautiful. I know that commercial processing and small farm bulk processing generally shakes them onto nets on the ground or direct into trailers, but why should I do that, when I can afford to be choosy about my olives?)
Add enough cooled brine to totally cover the olives, then put a clean board (or ceramic crock or rock or whatever you have that won't taint the brine) over the olives to hold them down, and cover the top of the crock / tub with a towel or cloth or loose fitting lid to keep insects and other rubbish out. Also, keep light out. Light is the enemy, it'll fade their colour rather quickly.
After a few days, the brine will have acquired a bitter taste, that's the bitter polyphenol compounds leaching out of the olives. Drain the brine, make a new batch, allow to cool, and repeat the process. After a few changes of water, the olives themselves won't taste so bitter any more.
To be honest, there are a load of formulas that people will give you regarding changing the brine daily or every "x" number of days, and putting the olives through "z" number of changes of brine and then they'll "be done." I do mine every few days (and up to a week) when I remember them, and after a few weeks I start taking out an olive before I change the brine and tasting it. If it's still very bitter, I do a change of brine. If it's just slightly bitter, that's when I stop brining and bottle them off.
That point is generally between four and six weeks for me depending on ambient temperature, because I like a bit of the strong flavour. You may want to process them longer. Shorter processing leaves a hint of the bite, and a crisp and tart olive. Longer processing mellows out the flavour but leaves a mushier fruit. Your call. Younger olives have that crisp bright taste, and stay crunchier after processing, older olives get a more mellow taste and texture.
(An Interesting Thing About Black Preserved Olives: Some operators buy olives that are grown specifically to be table olives when black, because these will retain their texture and flavour through the processing. Others buy green olives and dye them black... Add lye processing and you end up with a dull, rubbery, and bland tasting product. Caveat emptor.)
Washing: I only wash my olives off with clean water just before bottling them, because my brine is generally light and I like the saltiness anyway. Because almost all batches of olives will have white mold (see below) the rinse is a good idea just to remove the white granules. Some people leave the olives to soak for a day or two in fresh water, this does change the flavour slightly of course.
In general, I prefer a slight bitter edge to my olives at this stage, and to rinse / leach them as little as possible. Every leaching, be it with brine or fresh water, removes some of the flavour, and why should I turn my olives into a bland product? Also, bottling will mellow out the flavour over the ensuing months, so I may as well start with as strong a product as possible. Again, use your judgement for this. You may prefer a more delicate flavour to a robust one.
Bottling involves a brine around an eighth the strength, sterile clean jars, a few shreds of garlic or basil or lemon or some combination thereof, and using the brine as hot as possible.
The olives go in the jars and pack as tight as you prefer, but need to be held under the surface of the brine. I generally cut a circle of white plastic out of an old milk bottle and wash it, then use it to hold the olives under in the "shoulder" of the jar, then pour boiling hot brine over until it covers the olives and the plastic disk. Shake the jar to get the bubbles out, add more brine if necessary to cover, then add a thin layer of olive oil over that before closing the jars while everything's still as hot as possible.
I've never tried hot water or pressure canning, not even sure if it can be done with olives - because my olives never have to last more than a year, and I know they'll actually keep at least two years just done like this.
Brining Tips: I tend to change the brine only once or barely twice every week, because I'm basically lazy. Changing the water two, three, or four times a week will leach the bitter compounds out of the olives faster and give a slightly crisper crunchier product, but changing every week is okay too.
I tend to not tightly fill my vats with olives so there's a lot more brine in relation to the olives. In a high density situation where the olives are tight packed and barely covered with brine, you'd need to change the brine more often. The trade-off is that the longer the brining process takes, the softer the fruit will become at the end of the process. But softness also depends on the leaching of the fruit, so more frequent changes of brine also tend to soften the olives a bit more than leaving them in brine longer.
Making a stronger brine leaches the olives faster, but more salt also tends to change the texture of the olives faster, and then when rinsing and bottling, more salt will leach back out of the olives, meaning a lighter brine should be used for the bottling, or a longer soak in clean water may be needed.
Also. Worth noting that running water alone has been used, tidal sea water, and pretty much every strength brine from clear water to solid rock salt. You're sure to find a method that you prefer, and that works for you.
Brining Secrets Of The Lye Brotherhood: Using lye (caustic soda or in other words, drain cleaner) to leach the polyphenols out of olives is a quick process, it can take as little as 24 hours. But it wrecks the texture of the olives, and you then have to leach the lye out before you can bottle them off, and yeah - yuck!
I know, I know - wood ash lye has been used for at least hundreds of years to process olives, but the olives end up dull and listless. Shoot me, but I don't like lye processed olives.
Guilty Admission: Once, I changed the brine only twice in four months with a 30 litre tub of olives. Life got busy, the olives got forgotten, then forgotten again. Some months later, I realised that I'd probably just wasted a lot of olives. I opened the lid, and there was a thick rubbery white substance over the surface of the vat. It seemed to be part solidified olive oil, partly composed of the white mold that always accompanies olive brining. (More on this mold in a moment.)
I lifted that rubbery cap off, threw it in the compost. I was preparing to do the same thing with the olives, but first... You know, I had to check that they were really dead. There was no horrible mouldy smell, no ghastly dead yeast smell, in fact, they smelled perfectly like normal olives. Rinsed one off and ever so reluctantly tasted it - it was perfectly good! Maybe a bit softer than I like to process mine, but still good. I bottled them and used them for cooking for the next six months. Perfect!
White Mold: When you open your olives in brine if you leave the brine for more than a few days between changes, you may notice a few grains of a white mold growing on top of the water. I get it on every batch I make, I tend not to wash the olives before processing, and I think the organism responsible lives on the olives. I've heard it said by a friend who has been doing olives every year since boyhood that it's part of what gives olives the proper flavour, and should just be rinsed off the fruit before bottling.
If the olives smell like ass, then a wild yeast has gotten in there and I'd ditch that batch and sterilise the vat. But a slight sour smell (like vinegar or sauerkraut) is okay. The "ass" smell is because many wild yeasts excrete some pretty yucky substances.
Pink (Or Other Colour) Mold: is a no-no. That is all.
The crumbly "cottage cheese" type white mold is normal with olives and according to people with more experience than me, actually forms part of the process and flavour. Any other colour mold is likely to be anywhere from mildly to wildly toxic.
Salted Black OlivesTo make salted black olives, you just do that - medium fine rock salt, unwashed but cleaned small black olives, put in layers into a tub and covered with more salt, then a cloth. Every day, put a board over and tip off the salty black liquid, add more salt if necessary. These are done after a week to six weeks, and can just be left in the salt but loosened up from time to time, once the liquid stops running out. Or you can let them sun dry and pack them that way. Traditionally these are done in wooden crates so the liquid runs out, and are turned over once a day until ready, then freed of salt and dried.
Salted black olives are great to take on picnics and as part of ploughman's lunches etc. They're also used a lot in cooking. They stop absorbing salt at a certain level of saturation, and are actually quite mild considering how they're processed.
You can also make the small black olives in a fermented style that I haven't tried yet, but I imagine if I was was to, I'd completely submerge them in about a 3% by weight brine (3g salt per litre of water) so that the yeasts and bacteria on the olives could cause a form of lactofermentation, and then dry them and perhaps pack with a sprinkle of salt once they're done enough. Apparently this process can also be done with large fancy green olives, but they're bottled in their own brine once fermentation stops. I can't offer much on this process yet but I'm definitely up for trying once our trees produce a decent crop or two.
Olive OilI've watched the process and assisted but never had the gear to do it myself. The olives are crushed and pressed. The pits (stones) are just wood, they neither contribute to the final product nor do they seem to detract from it. I honestly can't remember if the olives were taken off the stones before crushing or if the stones went along for the ride. The stuff that came out of the grinding / pressing process was pretty much pulp, in any case.
What's left after crushing and pressing is a liquid pulp, and that then went into a "malaxator" which is a bath to allow the oil to separate out and form droplets suspended in the pulp. Some gentle agitation is involved from memory. Then it goes the oil extractor which is a set of rotating plates that the oil droplets stick to, leaving the water and fruit pulp behind, and then the plates are scraped of oil, and go back to collect a new film of oil, until the oil's been all extracted. In the friend's setup, the malaxator also had the plates and scrapers in it, from memory.
Last thing is filtering, and my friend's filtering was pretty basic with layers of some fine material that the last remnants of fruit and stones in the oil was squeegee'd through and the oil forced out. Apparently there are good commercial filters but they're expensive.
Also, green olives give a superior green oil but of course being less ripe, there's less oil to be had. Black olives give a less green oil, but occasionally leaves may be crushed and pressed to put some green colour back into the oil. And lastly, there are always dishonest operators out there who'll use green dyes, admix other cheaper vegetable oils, and so forth. All I can say is buyer beware!
There is a "lye" processing method for olives, which reduces the saltiness a bit and apparently works a lot faster. You proceed as for salt brining but use a solution of lye instead. After a soaking in lye, you soak the olives in plain water or very weak brine for a few times to remove the lye, then proceed to bottling.
I generally use a 30litre brewing vessel for brining, it's easy to use, easy to drain the brine when it's spent, and the little airlock thing allows gases to escape but keeps yeasts and bacteria out. I generally wrap it in a few towels too, keeps light out and stabilises temperature a bit.
Almost everything about olives is a bit of a "suck it and see" approach. Taste a green olive direct from the tree, taste a black olive. A tiny shred is all it'll take, and it will not kill you. Taste as you go with processing, again, you'll learn how the flavours develop, and it isn't harmful.
Friend's olive oil processing was very similar to this machinery. I have to say I thought he had more money than sense, because he didn't (at that stage anyway) process olives for anyone else.
I also worked for part of a few seasons on a farm that had several thousand olive trees in about four groves, and helped hand pick olives for the fancy pickle market. As my reward for that, I was given the pickings of one particular tree that, apparently, none of the farmer's customers "wanted." I got around thirty kilos out of that tree in perfectly beautiful fat green fruit, and they processed better than anything I'd had before.
This relates to the last remembrance (of my friend's olive oil equipment) because they were less than fifty miles apart, and this farmer sent his olives to a commercial miller to be pressed, and thus he lost control over a very important part of the process. Also, he was looking for a variety of ways to value-add the olives he had rather than just sending them to be turned into oil, but never got past the stage of experimenting.
And lastly here's an article that delves briefly into the whole olive business. It's just a rehash of what I've alluded to above, but gives a few extra tidbits of info.
Very lastly - I am not any kind of expert on olive processing. But then again, neither were the people who originally processed olives to form part of their diet. Doing things is the best way to learn.