How to Make Olive Oil

olive varieties for oil and pickling

So last week we shared how not to press olive oil at home  and all the things that didn’t work. This week we’re on a more positive tack talking about how to not only press olive oil but also how to grow, harvest and pickle the little green globes of goodness.

First you need to select the varieties that are best for your purpose.  Above are some of the most popular olive varieties for growing in New Zealand, going clockwise from top left:

  • Frantoio – a Tuscan variety, self fertile, a good oil olive
  • Leccino – a Tuscan variety, self fertile, oil or pickling
  • Pickling Olive – a great variety from Geraldine’s place that I’ll get the name of for you.
  • Pendolino – a good pollinator for other olives and a dual purpose pickling / oil variety
  • SA Verdale – some call it the cold climate Kalamata, definitely a good pickling olive
  • Koroneiki –  a tiny olive that makes an intense peppery green oil

Missing from this list is Picual which is a good Spanish dual purpose pickling and oil variety of quite large fruit and Barnea which is a vigorous tree and an early variety of many NZ olive groves.

Olives are wind pollinated and benefit from a few pollinating trees dotted throughout a grove.   When they get older a prune can help promote vigorous new growth for fruit production but by and large you just leave them to get on with it.   They are relatively pest free apart from birds as the crop reaches ripeness. You don’t get a meaningful harvest until trees are around the 10 year+ mark. These trees below are in a friends olive grove and they are between 12 and 15 years old. They let us pick a couple of crates of fruit last year after we helped with their harvest.

making olive oil at home

Olives are an Autumn harvest. Here in Nelson we harvest around early June each year. Large groves have mechanical tree shaking machines and nets but if you’ve only got a few trees your best method is to spread windbreak cloth or similar underneath the tree and “rake” the fruit off with these plastic olive rakes.  For a mellow oil you can pick fruit when 1/3 is green, 1/3 is green black and 1/3 is black.   An all green harvest will yield a quite peppery green flavoured oil which I personally enjoy.

Four adults can pick 30 kilos in a couple of hours and then you spread them out and “leaf pick” any stems and leaves in amongst it to further improve the quality of the pressing that is to come.   After picking it’s best to get the fruit to the press within 48 hours to retain the fresh flavours in the oil.  We took our precious 30kgs of fruit to our neighbours who invested in a proper small scale olive press a couple of years ago.   This press is made in NZ by Axis Industrial and takes around 30kg of fruit at a time.

malixing olives

As we know only too well, pressing olives is a 3 part process, the first step is grinding the whole lot into a guacamole like paste and you can see by my grin that after all my trial and error in this department I’m loving the ease with which this machine grinds the whole fruit, stones and all. Next before pressing is a malaxing process where the olive mash is paddled around large pots for half an hour or so to soften up and emulsify the oils prior to pressing.  This increases the extraction rate.

pressing olive oil

Next we load the press, paddling the olive mash into the vat and sandwiching it between plastic mats in a layered cake. The mats have ridges in them that help the oil escape. The top is turned down and there is also a nifty car jack (see I was on the right track) fitted to the bottom to exert some extra hydraulic pressure for the final extraction.

pressing olive oil at home

The oil seeps out the fine stainless steel mesh basket and collects below into a stainless bucket.  From here it is emptied into a long cylindrical settling chamber with a hose tap at the bottom and at the top. Over 24 hours the oil settles and then you connect up the bottom hose to the tap and turn it on to raise the settled oil from the bottom to the top, clear part of the chamber and you turn the top tap on and siphon it off into clean glass jars which you then let settle for a few weeks and it’s ready to use.

If you think that sounds like a  lot of work then you’re right but it was really enjoyable work and we got 3 ltrs of really high quality grassy green olive oil which kept us going pretty much all year in salad dressings, dips and marinades. So an afternoons picking and pressing doesn’t seem like that much of an imposition … hey I could have tried using the kitchen whizz… what was I thinking :).  For every job there is the right tool.

And if you’d like to pickle a few olives then here are two recipes that we’ve tried.   One is Geraldines family recipe which came from an article in the Nelson Mail years ago and has been the mainstay in their house.   The other recipe is from NZ Gardeners Get Growing e-zine last season and is an equally good recipe with a few more variations thrown in.   Click here for pickling recipes.

 

 

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18 comments

  1. Hi Heather
    I love your newsletter and I miss browsing your shop when I’m in Mapua.

    I have a huge problem with my olives this year. The 2 trees are about 12 to 15 years old and having had plenty of olives to pickle every year it is sad to see that this year they are rotting on the tree even before they are ripe – possibly 75% !!! I am hoping it is something to do with the weather here in Nelson!! Or do they have some disease? I have to admit to doing nothing to these trees and every year they just keep producing great fruit.

    Hope you can help – I can send photos if you like

    Ruth

    Ruth’s Olive Recipe:

    Pick your olives and put into a large bucket, cover with water and weight down (with a plate and a stone)
    Change water every day for 10 to 14 days
    Transfer olives to large jars – I use glass with a stopper
    Then dissolve:
    600 gr salt into
    6 litres water and add
    600 mls red wine vinegar

    Pour over olives to generously cover
    Top with olive oil to stop air

    Enjoy approx 3 to 6 months later or take some out and add whatever spices, garlic etc you like mixed with olive oil.

    1. Hi Ruth, thanks so much for your recipe, I like the sound of that one and will give it a try with this seasons crop. I don’t know why your olives are rotting this year, it’s not been a particularly wet autumn. I’m picking olives on Friday and I’ll consult amongst my fellow pickers to see if any of them know. The folks I’m picking with all have small commercial groves so one of them will have come across it no doubt. Cheerio. Heather

    2. Hi Ruth
      It would seem that olive rot or Peacock Spot, both fungal diseases, may be the problem. Or it could also be frost damage as we’ve had a few frosts already. If it’s a fungal disease a liquid copper spray (after fruiting) is recommended and remove any fallen fruit from under the tree and copper spray again in spring before flowering. Hope that helps.

      1. Hi Heather
        Thanks for the tips and I will definitely spray with copper and hope for a miracle! I had encouraged several of my friends to give it a go with my surplus but they’ll have to wait another year
        Cheers
        Ruth

  2. Olive pressing did not disappoint, but I love your cabbage bowls! They remind me of those old franklin the turtle books. Where did you get those?

    1. Hi Carmen, thanks for your comment. The cabbage bowl was a gift from my sister who knows how I love old green china 🙂 Bets on she would have got it at a garage sale :).

  3. I would like to purchase a stainless steel basket and the mats like you show in the picture.
    I would appreciate it if you could tell me where to purchase them. I can make the press and
    other components.

    Thanks

    Stephen
    Belton, Texas

    1. Hello Stephen, thank you for your comment. Try Axis Industrial based in Auckland – they may sell you the baskets and mats as separate components. Good Luck. Heather

  4. Hi,
    Thanks very much for your posts/info.
    Unwilling to invest too much $, I am still at the stage of how “not” to make olive oil, but I have found a satisfying solution for smaller batches.
    First, we live in Perth WA, 700m near the coast. We have 3 olive trees of different cultivars (not sure what types).
    I pick the olives, lay batches of 30 or so on a wooden board and smash each one with a hammer to pop the skin (you need to point the stem side away from you otherwise yours shirt gets splattered!). You don’t need to hit them too hard.
    Once the skin is smashed, just take out the seed and then place the skin/pulp onto a baking tray.
    I then put the baking trays outside on a garden table and place a sheet of glass over the top of the trays, allowing a 3mm air gap. Depending on the weather, these are dry enough to press after 2 days. I then use a hand cranking screw press I got from Alibaba for about 200$. There’s no need for water separation with this method.
    The oil has a toasty taste but not bitter. It reminds me of popcorn and its great for dipping.
    Thanks again for sharing your information !

    1. Hi Matt, classic method you’ve got there. I’m intrigued to find that you are getting a palatable oil with this drying method – I think I over dried mine when I tried this. With your Perth sunshine I’m sure they dry well. What fun. If you come across a better press let us know. Thanks for sharing. Heather

  5. Hi, we want to buy some olive oil press machine, could you advise some suppliers for me? thanks

    1. Hi Rita, try Axis Industrial in Auckland.

  6. Hi there.
    I’ve enjoyed reading both of your blogs how not to and how to make olive oil and now want to DIY our own but having trouble finding a machine that is affordable. I checked out axis as mentioned in a previous comment, but their machine was over A$10,000 which is ridiculous for using at home. Would you have any other suggestions? We too live in perth close to the coast and have a couple of trees which are loaded with ripe fruit at the moment. Thanks for your info.

    1. Hi Lee, sorry I too am still on the search for a cost-effective home olive press. First to find one please spread the word here.

  7. Hi, I am facing the green sludge jar in the kitchen after adding the 20-40% of water to my industrial strength blender filled with olives.
    Sure made a bad tasting guacamole that pressed ok but the majority of the droplets are tiny and still suspended in the water.

    I just came across this hand crank and wondered if anyone has tried it?
    https://www.piteba.com/eng/olives.html

    All the best
    Per Norrgren
    Algarve, Portugal

    1. Hi Per, thanks for sharing and yes I did talk to some folks here who have the piteba – it’s a great machine but alas not up to pressing olives – the marketing is somewhat misleading – kind of suggests it can but no – it can’t.

  8. Hi Heather. Do you have any suggestions for how KIDS can make olive oil in a classroom setting? Limited equipment, budget and time, etc. I want to write a lesson for our non-profit Sunday School site and would be glad to give you a linkback and plenty of credit!

    1. Hi Neil, I’d get them to squash some olives between two sheets of paper towel with a hammer and look at the oily mark the olives leave on the paper. I can’t think of a way they’d be able to get olive oil without serious effort and equipment.

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