Olive – Olea europaea
Contributed by Linda
Originating in the Middle East, the olive tree grows to 4-7 metres with a spread of 5-7m. Olive trees can live for a 1000 years! Olives/olive oil is said to be largely responsible for the low incidence of heart disease in Mediterranean countries. Olive trees are great for providing shade and can be used as a screen tree/hedge with its silver elongated leaves.
Varieties of olive trees
| Kalamata | Large fruit. Needs warm summers for good production. Can be used for oil production |
| Manzanillo | spreading tree bearing early crops of medium sized olives which can be picked green or black |
| Verdale | Fruit is best pickled when green, but can be pressed for oil in areas with very hot summers |
| El Greco | Comes from New Zealand. Good reliable crop or medium sized fruit. Good oil content. |
| Mission | Medium sized fruit with average oil content. Good for pickling at the blue-black stage. |
| Servillano | Bears very large fruit but low to average oil content. Excellent for pickling. |
| Ascolano | Large fruit with small stone. Good for oil and pickling |
Planting
Olive trees can be grown in regions where the temperatures can drop to -10°C but fruiting will be hindered if exposed to frost for any length of time. Plant your olive tree in the warmest place in your garden though the setting of the flowers requires a light winter chill. They are intolerant of wet or poorly drained soil.
When first planted, chose several leaders to train up into an open round shape, leaving a clear metre to the ground. Olives bear on the previous season’s growth. Olive trees will have flowers with both male and female parts and so are self-fertile. Some flowers are male only so will not produce olives. They will grow on any rocky dry hillside (such as in Spain and Greece) but will grow faster in good deep soil with adequate water. Application of ‘blood and bone’ also aids growth. They are best propagated from cuttings by taking a 40cm piece of hard wood and sticking it deep into the ground. There is no need to prune olives but light pruning will produce more fruit.
Harvesting
Flowers set in late spring followed by the fruit in late autumn. Cropping can begin any time after 5 years of growth. In some years you will obtain a bumper crop, in others, nothing! This biennial bearing can be overcome by thinning the fruit to no more than 10 olives per sprig.
Picking can begin when the fruit is turning from dark green to light green or you can wait for them to turn black (but still firm) for black olives.
Pruning and training
Keep the centre of the tree open for ventilation and prune out vigorous upright growth. Remove any old unproductive wood and any interior cross branches. Fruit size can be increased by thinning to 3 olives per 30cm of branch.
Extracting olive oil
You will black or nearly ripe olives which are harvested about mid-winter for maximum oil. Olives can be taken from the trees by shaking the olives onto a tarpaulin or sheet if you want to avoid the laborious hand-picking. To crush the olives and their stones you can use a coffee grinder but there are small crushers on the market. When the olives and the stones are crushed they are ready for pressing. Make a sack out of clean canvas and half fill with your olives. The oil is then pressed out of the sack. For large amounts it is worth investing in a permanent screw press. If this sounds like too much hard work, you can take your olives to a commercial factory which will give you a percentage of the oil pressed out.
Pickling your own olives
Method 1
Place the olives in a wicker basket or an old fruit box with holes in the bottom. Cover the olives with a finger-thick layer of salt. Leave the olives in a cool place for 24 hours. Put gloves on and mix the salt and olives. Do this once a day until the olives look wrinkled. Add more salt if necessary. The whole process will take about 6 weeks and by then most of the bitterness will have been absorbed by the salt.
Store the olives by washing off the salt and storing under olive oil.
Method 2
Prick each olive with a fork or slit with a serrated knife. (This will allow the salt to penetrate the fruit and take away the bitterness.) Toss them immediately in a bucket of clean water in which half a cup of coarse salt has been added to every 10 cups of water. Place a clean plate on top of the olives to keep them submerged at all times. Pour the liquid away each day and replace with fresh brine. Repeat this process for 12 days for green olives and 10 days for black olives. To test for the removal of the bitterness, bite into an olive. When the bitterness is almost gone, the olives are ready for the final salting.
Pour off the liquid and measure this quantity. This volume will be the storing volume. Measure out this volume of warm water and dissolve the salt but this time use 1 cup of salt to 10 cups of water. Boil the water and then cool.
Place olives in bottles and cover with the brine. Top with a layer of olive oil, seal and store for at least 12 months in a dark cool place.
When you are ready to eat your olives, pour away the brine and cover the olives with clean cool water. Leave in the fridge for 24 hours. You can then add flavourings of your choice.
This might seem a long process, but it is worth the effort and think of the savings you have made from not buying off-the-shelf commercial olives.
