how must you grow olive trees to obtain the best evoo?

How must you grow olive trees to obtain the best EVOO?

1. Characteristics of olive trees

A millennial, long-lived plant, of which there are more than 200 varieties in Spain and around 2,000 globally. Even if it has been planted all over the world, olive tree is mainly Mediterranean, a territory in which they acquire their true dimension. Curiously enough, olive trees have been classified under the botanical category of bushes.

They do not require great amounts of water and are very resistant to draughts. Many hectares of olive groves have been planted in irrigated land but, even if it improves production, the oils obtained in dry land with lower productions have clearly better organoleptic qualities.

2. Plantation types

Until about 40 years ago olive plantations were made covering branches with stems in holes in the ground and directing the sprouts later. Usually, when olive trees had grown, the central branch was removed (the divider) to open them in 3 or 4 branches or “legs”. That is how traditional plantations were organized.

At present olive groves have just one leg and hectares are denser, plants are prepared in greenhouses using thenebulization technique. Upon plantation, they must be protected against rodents and guided. In this first stage, they must be looked after with extreme care, as they are very sensitive to pests that do not affect mature olive trees.

3. Soil adaptation

In general, they adapt well to all kinds of soils, but for an excellent olive quality we need draining soils with plenty of organic matter. Andalusian soils are basicallylimestone and therefore they may block the synthesis of essential minerals such as phosphorus, potassium, nitrogenous, boron or iron in different ways. We must do soil analysis every soften to determine any potentialdeficiencies and, to the extent possible, correct them through the soil or foliar treatments.

European regulation is more and more demandingregarding environmental conditions and fosters the maintenance of vegetable covers and cultivation abolition in olive groves. Grass is cut and pruning waste is also grinded and left on the ground to create organic matter, which will result in a better harvest quality and quantity; it is also useful to prevent erosion, one of the main reasons for soil mineralization. This system permits to extend roots all over the ground; this way they grow bigger and absorb more nutrients.

In certain periods the use of contact herbicides is allowed to keep the area under olive trees clear of grass and facilitate the picking.

4. Frequent pests and treatments

Olive trees are plants very sensitive to fungus attacks(olive peacock spot disease), which proliferate easily when there is humidity and heat and affect leaves and fruit, diminishing and decreasing the quality of the harvest. It can be prevented with copper-based treatments, an important fungicide applied at least in spring and autumn with stock dissolved in water wetting the tree. These treatments are used to add foliar fertilizers.

Another common pest is the prays oleae, a worm that eats the olive when it is developing; it is very resistant. Moths lay the eggs and later neonate larvae start eating the olive husk. Treatments are highly regulated, they attract moths to traps with pheromones and make a regular recount to determine if treatment is suitable or not; they also analyse if eggs are fertile or not, as they dry up on high temperatures. Treatment is applied at the beginning of summer with propolis-based poison with security periods of 30-45 days in which the poison disappears.

Others, such as plant-destroying flies or larvae, which also affect harvest quality.

Trees absorb many nutrients facilitated in the treatments through the leaves; therefore, in the “dormant” period(summer) we must do leaf analyses to determine potential nutritional deficiencies.

5. Pruning

An important, essential task to preserve olive trees’ health and y vigour. It must be made in spring at the latest to prevent dormant periods in heat season, this is, that the low activity in sage ascents prevent new sprouts from coming up.

Pruning rejuvenates olive trees; we look for fresh“sprouts”, the most productive, and prevent an excess of wood (firewood), that diminishes productivity.

Pruning includes “desvareto” or removal of suckers around the base of the trunkas they diminish sage’s vigour, which must ascend to the rest of the tree.

6. Blooming and fruit ripening

An essential stage in olive formation, it occurs in spring and the determining time is when flowers turn into olives. It takes very few days but any climate alteration on those dates, due to cold or heat, may cause harvest depletion. In addition, rain may diminish pollination in this season.

7. Harvest

Olive is a winter fruit and, therefore, this is when its picking starts. If we go for table olives the harvest will start, depending on the variety, between September and November, always before the “envero” or intermediate stage of olives, they change colour from green to black. If we choose to grind them we can do it when they are completely green, purple (halfway) or black. The different stages are as follows:• Green olive: produces very fruity, spicy and in some varieties bitter oils, all of them with very powerful organoleptic qualities and a low-fat profile.• Purple olive: intermediate stage, the optimum one, less spicy, with no loss of organoleptic qualities and the fruit has experienced the necessary ripening.• Black olive: less spicy, more fatty profile and lessorganoleptic qualities. Even so quality oils can be produced with just ripened olives, but with less “hues”. There is a time, from February in Hojiblancaolives, in which sage gest with more strength to olives and it may result in the loss of qualities, producing «worse» oil.

A few important things when picking, regardless of the phase:1. Avoid hitting the fruit too much. Harmed fruit is very prone to fungi attacks and results in acid oil (we will analyse this parameter later). The vibration and milking system with gravity fall without beating the olives is the most suitable.2. Taking olives to the mill immediately after the day, even faster in hot weather. The sooner the milling the better the oil.3. Separating olives from those that have fallen to the ground whose quality will undoubtedly be poorer (we must always take into account the fearsome fungi).4. Cleaning leaves as much as possible, even if in the olive mill there is a process to do it.

8. Milling and oil production

In the old days, they did it grinding olives with conic stones that span around an axis and the dough went to a heat beater. This dough was put between hods and when pressed we obtained a juice that was then sent to a natural decantation process.

The industrial methods of this process have changed a lot, as it involved several faults that had a great impact in oil quality, such as:• It was a really slow process. There was no time to grind all the olives received, and it remained storedfor several days outdoors, with the resulting appearance of fungus, which increased acidity.• Hods were a permanent source of fungi when they were not cleaned properly between pressing processes.

Present oil production processes are entirely different and focus on obtaining the best “quality. We can say that upon their arrival it was difficult to find reasonable oils. Let’s see the process:• Olives are grinded with fast, modern and efficientelectric mills, with a great grinding capacity, which permits to mill the olives as soon as they reach the olive mill.• The dough goes to a batter that homogenises and heats. The higher the temperature, the higher the fat profile and the worse the oil.• Later it goes to a high-speed centrifuge that separates the solid part from the liquid one. Hods and pressure procedures disappear with this method.• It is then carried to a decanter that separates oil from the rest of liquid substances.• Then it goes to the tanks for a few days to let itrest” and they pack it. Obviously, they do not filter it. They use stainless steel tanks and tools at all times.

As you can see, we are literally talking about making olive juice here. We must forget about expressions such as «firstcold pressed», only used by those who do not know the industry well or want to sell something using fancy buzzwords.

9. Characteristics of oils

Fortunately, the concept of quality has entered with strength in olive oil consumption habits. Regarding the concept of fruit oils, obtained from early olives grinded as soon as they have been picked, in untreated olive grovesand with the recommended low-temperature molturation processes we are producing very appealing oils which have turned into “cult” products.

It is not a common fat, numerous studies confirm its multiple healthy qualities and this, together with its pleasant taste, allows us to ensure a successful marketing.

We can obtain single-variety oils or an oil coupage, a bland of different oil varieties. We must be cautious with these blends because we could destroy their individual properties.

Oil analytics are quite complex and you must assess many parameters with sophisticated techniques that allow us toexpress a reliable opinion on its quality.

“Tasting” are getting more and more popular and determine oil’s organoleptic qualities, taste, odour, aromas, etc. The results of these tastings are fascinating. Experts normally use expressions herbal, tomato and almond taste.

We must pay special attention to oil storage process. Basically, we must separate it from light and heat, so they must be stored in appropriate containers and locations.Nowadays there are stainless steel tanks where we can inject nitrogenous to that oil can be stored in air-tight, isolated conditions; in these conditions, preservation results are excellent.

10. The most frequent varieties of olives in Andalusia

Each olive produces oils with different properties; hence the importance of getting to know the possible maximums and choosing the most pleasant. Combinations both of single-varieties and coupage olives can be very different. These are some of the most significant.• Cultivated in the province of Cordoba, with medium yield, resistant to limestone soils, it can be used at the table and for high-quality oil. High detachment resistance and therefore hard to pick.• Area of Jaen, high yield, medium-quality, stable oil.• Good fatty yield, quality, low stability oil.• Adapted to limestone areas, high yield and quality, very organoleptic oil, resistant to detachment. Very spicy, frequently blended with Hojiblanca in an oil coupage. Typical of the Priego and Carcabuey area.• Wild olive trees produce small-sized olives. Very difficult management.

11. The future of the sector

The efforts made both to enhance quality and to offer attractive products in the market with good presentations are starting to give fruit. Spanish exports keep growing at a constant pace and our oils are starting to be more and more appreciated globally.

Il this future, traditional dry-land olive groves must play a relevant role as best oils are produced there, even if their production costs are much higher than those of modern mechanized irrigated plantations.

Many countries are planting olive trees and that must not be a cause for concern, but a proof that they are trying to supply part of their internal demand for this product because it is growing. We cannot forget that just 4% of the fasts for human consumption are olive oil. With a percentage increase of 1 or 2 points, there would not be enough offer in the market to stock it.

Certainly, the future demands quality, product diversification and excellence in getting to sell such an exquisite and healthy product.

The future also involves to keep doing research to get varieties more resistant to draughts and pests and that get adapted to different kinds of lands and climates. This is an extended field of work, but very promising. Banco de Santander has recently funded the research work of the Spanish National Research Council (CSIC) to decipherolive trees’ genome; the amount of information that can be provided by this wonderful, millennial tree is incalculable.

12. Details of the “Monte de Torres” plantation in La Hoz estate

Located in the municipal boundary of Iznajar, 3 km away from Rute, in La Hoz estate and in the Subbetica of Cordoba, in a mountain area of about 19 Has with around 1,800 olive trees, most of them planted in the traditional manner and of the Hojiblanca variety.

Previously this estate was a forested area that, when my grandfather was young, was “broken up” to plant olive trees; this helped to generate a great amount of daily wages at a time when work was very scarce. They are about 100 years old.

Soils have a great drainage capacity and, as they are in the mountains, trees enjoy airy and sunny conditions. No works have been performed in the soils for more than 40 years and pruning waste and grass are left on the ground. We can say most certainly that this is a vegetable land with plenty of organic matter.

Productions are limited, even if the neighbours say that this is a very «fruitful» estate, this is, that flowers always turn into olives and, with more or less incidences, has an olive harvest almost every year and «fresh» because, as this area is quite stony, the land preserves humidity better.

The harvest process is quite hard. For example, in the steepest areas, each operator can pick an average of 200 kg when i other estates with loaded olive trees you can pick about 400-500 kg per person.

This is the basis of oil quality. As a significant and distinctive detail, it is worth noting that the best oils in the world have been obtained from Hojiblanca olives and that three olive mills of the Subbetica of Cordoba are among the most awarded olive presses in the world. There must be something in it.

13. Glossary of terms

1. Envero: intermediate period when the olives change the colour from green to black; olives acquire a purple and iridescent colour.

2. Oil acidity: the lower the acidity, the better the quality. In EVOO, it must not be over 0.3 grades.

3. Fatty yield: part of the oil obtained per each kg of olives, which may vary between 10, 20 or even 25%. Hojiblanca’s yield is low; the earlier the harvest and the lower the oil production temperature, the better the quality.

4. Unfiltered oil: no filters added.

5. Organoleptic properties: taste, scent, colour, aroma, density. We can say that all senses are involves in their appreciation.

6. Atroje: keeping olives without grinding them. Involves an increase in fungi and acidity.

7. Coupage: combination of oils of different varieties of olives.



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