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.
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.
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.
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.
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.