Posts Tagged ‘Fruity Oils’

Why do olive oils taste different? 

Whilst Extra Virgin Olive Oils share common characteristics, there are marked variations in quality and taste. The IOOC’s categories  of  ‘fruity’, ‘bitter’ and ‘pungent’ are used to categorise its flavours but these are strangely negative terms for positive attributes and cannot convey the nuance of flavours or aromas that characterise individual oils. It is more common to see descriptions such as ‘delicate’, ‘light’, or ‘buttery’ for mild oils, ‘semi-fruity’ for medium oils and ‘fruity’ for oils with a stronger olive flavour.

There are significant differences between the flavour, appearance and aroma of olive oils, even within the same country. For example the characteristics of Italian olive oils range from the thin, green, peppery oils of Tuscany to the rich, buttery oils of Liguria and the fruity oils made around Lucca.

Just as the flavour of a wine is principally determined by the variety of grapes used to make it, so too is the flavour of olive oil. Olive oil is made from a wide variety of olives that produce distinct differences in flavour. The two major influences on the character of an olive oil are olive variety and maturity. There are other influences as well, such as climate, irrigation and processing method, but these usually have a lesser impact.

Variety

There are thousands of different olive ‘cultivars’ or varieties grown throughout the Mediterranean and the wider olive growing world. Italy alone has over 700 different varieties, each with its own distinct character that gives a unique flavour to the oil it produces. Olive cultivars differ from each other in many different ways, most noticeably in the shape and size of the olives and the shape of their stones or kernels. Cultivars are selected depending on the growers specific requirements matched against their growing conditions. Varieties selected for the production of table olives tend to have large fleshy fruits and small kernels, such as the Kalamata Olive, whereas others are selected for their high oil content, such as the Picual Olive. Regions are often strongly associated with certain types of cultivar, for the most part as a result of what has traditionally grown well in the local climate. This is beginning to change as growers look to introduce new cultivars to improve their stock and the flavour of their oils.

The main determining factor in the flavour of an olive oil is variety used. Despite the wide variety of olive cultivars most of them are inferior to the few varieties that have come to dominate oil production throughout the world. The most popular varieties are hardy, productive, healthy and suitable for intensive cultivation and as such they can be found all around the world. Picholine (from Spain), Koroneiki (from Greece), Leccicino and Frantoio (from Italy) can now be found far beyond their native soils. Whilst these super-cultivars threaten the local biodiversity that has characterized olive oil production to date, they have improved the quality of the product, yields, hardiness, drought resistance, resistance to disease and suitability to more intensive farming methods.

Every Extra Virgin Olive Oil contains a unique mix of different phenolic species with each producing different degrees of bitterness and pungency³, these individual differences in bitterness perception could help to explain the observation that oils with widely different phenolic levels were classified into the same style class by different individuals. Furthermore, as the producers assessed the style of their oil based on the combined percept of bitterness and pungency, it is likely that differences existed between individuals with respect to how they internally summed the intensities of the two percepts in arriving at an overall style classification.

The concentration of phenolics in olive oil fundamentally affects its taste by contributing to its overall bitterness and pungency¹. The level of these taste attributes in a virgin olive oil determines how it is best used² with intensely bitter and pungent virgin olive oils best suited to preparing strongly flavoured foods, while those that are low in bitterness and pungency will best complement delicately flavoured foods. This is because intensely bitter olive oils can overpower the nuances in flavour of delicate foods, and conversely the character contributed by an oil low in bitterness and pungency will be largely inconsequential to an intensely

flavoured food.

Different olive varieties also have different polyphenol concentrations. Some varieties, like Coratina and Picual, are naturally high in polyphenols, other varieties, like Arbequina, are intrinsically lower.

Some oils are made from a single fruit, for example using Koroneiki, Leccino or Picual olives. However, some of the very best oils are made from a carefully selected blend of several types of olives. The choice of cultivar, time of harvest and the ripeness all affect the oil content of the olive.

Maturity

Olives can be harvested for oil at a wide range of ripeness, from completely green to completely black. When a green olive is pressed for oil it will generally yield oil with a higher level of bitterness and pungency. This is because the polyphenol content of an olive decreases as it continues to ripen on the tree. Polyphenols are the compounds that contribute the bitterness and pungency to the olive oil and also provide many of the health benefits. The antioxidant properties of the polyphenols explain why greener harvest oils have a longer shelf life than ripe harvest oils; the natural antioxidants slow the onset of rancidity in early harvest oils. One of the trickiest parts of making an olive oil is timing the harvest. Harvest too early and you can have oil that is aggressively bitter and overwhelming. Harvest too late and you may produce oil that is bland, lacks character and will become rancid in too short a time. A good producer knows his or her varieties and harvests them at the peak point to make the most of that cultivar’s qualities.

Other influences

Biodiversity means that the same cultivar will perform differently in different conditions. One of the best examples of this is the Arbequina olive, depending on where this olive is grown it gives a very different oil: when grown in Andalusia it produces a much fruiter oil than when it is grown in Catalonia where it delivers a softer, herbaceous oil. Similarly, oils made from Leccino olives are richer and more rounded in Puglia than Leccino oils from Tuscany.

What are the attributes used to describe olive oil?
The sensory evaluation of olive oil follows defined standards developed to determine the quality of the oil. The fact that there are more negative attributes than positive attributes reflects the importance of weeding out defective oils. The positive attribute “fruity” includes an entire world of olive oil flavour nuance and individuality; it is here that more descriptive detail helps to paint a fuller picture of an olive oil. In 2007, the International Olive Oil Council (IOOC) added some additional descriptors for labelling purposes. These terms add more detail to the positive side of the evaluation equation. Table 1 Shows the IOOC’s tasting sheet:

Table 1

The Primary Defects of Olive Oil

Fusty/Muddy Sediment – This defect happens in oil obtained from olives stored in piles which have undergone an advanced stage fermentation. It can also occur when oil has been left in contact with sediment which settles and ferments in the bottom of underground tanks and vats

Musty – A characteristic flavour of oil made from olives in which large numbers of fungi and yeasts have developed. This can happen as a result of olives having been stored in humid conditions for several days.

Winey/Vinegary – This flavour is mainly caused by fermentation within the olives or the olive paste left on pressing mats that have not been properly cleaned leading to the formation of acetic acid, ethyl acetate and ethanol.

Wet Wood/Frozen – This flavour develops in oil made from olives which have been damaged by frost while still on the tree.

Rancid – This flavour affects oil which has undergone a process of oxidation.

The positive attributes of olive oil

Fruity – This characteristic depends heavily on the variety of the olive and is the result of oil made from fresh olives, either ripe or unripe.

Bitter – The taste of oil obtained from green olives or olives turning colour.

Pungent – This is characteristic of oils produced at the start of the harvest, primarily from olives that are still unripe, and is commonly described as ‘peppery’.

Optional terminology for labelling purposes from the IOOC

Greenly fruity – Characteristic of oil that is reminiscent of green fruit. It depends on the variety of olive used and comes from green, sound, fresh olives.

Ripely fruity – Characteristic of the oil that is reminiscent of ripe fruit. It depends on the variety of olive used and comes from fresh olives, green or ripe.

Well-balanced – Oil in which fruitiness is the dominant characteristic, but still in harmony with the oil’s  bitterness and pungency.

Mild – An oil in which bitter and pungent flavours are slight or not present.

Which is the best olive oil?

Which is the best olive oil? Which country or olive variety or technique offers the best result? There is, of course, no correct answer. What constitutes “the best” flavour is a highly subjective matter; it is a matter of taste and also depends on the intended purpose.

Fortunately, Lefktro offers you so many wonderful and distinctly different olive oils from all over the world that you’ll have the opportunity to explore the range and discover your favourites for yourself!

1. Guitierrez et al., 1989; Andrewes et al.; 2003
2. Cerretani et al., 2007
3. Gutiearrez-Rosales et al., 2003; Andrewes et al., 2003