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The unbearable seductiveness of the young olive oil

by Gogo on November 13, 2009

in Olive oils

A good olive oil is born to be wild, but in few months it becomes tamed and smooth. For those like it wild, here is a piece of advice on how to keep it that way for a while longer.

When it exits from the olive mill olive oil is like a freshly pressed fruit juice. Its aromas are intense and deliciously fresh, in mouth behaves wildly, it bites, and it is often peppery and bitterish. In two or three months its wild taste fades away and then the oil is usually sent to market (they say it becomes more equilibrated but I would say it is just more adapted to the taste of the common people).

Young olive oils made from

Young olive oils made from 100% "Buža" (left) and 100% "Leccino" (right) olives. Observe the difference in color - the left one is more yellow, the right is dark green.

There are certainly people who would like to buy an olive oil that keeps its initial character throughout the year, not only in the first few months. But, is it possible to produce such oil? To answer this question, we first have to find out why the young olive oil has such intense aromas and flavors.

First step – The young oil has cloudy appearance (see the picture above). It is cloudy since the olive mill does not perfectly separate the liquid from the solid part of the olive paste (olives are first ground into paste), causing that some tiny solid particles inevitably escape to the oil. Maybe exactly these particles – plant material originating from ground olives – contain a lot of molecules responsible for intense aromas and flavors of the young oil?

To test this hypothesis we have first to remove the plant material from the oil so that it becomes transparent. Then, we smell and taste “the cloudy” and “the transparent” oil one after the other and see if the intensity and quality of aroma/flavor is different or not.

For the test I used two oil samples (see the picture above). The first oil I got from a friend of mine – it is two weeks old and made entirely from “Buža” olives, an olive cultivar indigenous to Istria. The second oil was produced by my family – it is four weeks old and is made entirely from “Leccino” olives, a Tuscan cultivar very popular in Istria (by the way, to show their support for Manjada blog, my family named our oil Oio Manjadico; in English – The Oil of Manjada. Here is how the bottle looks like.)

Oio Manjadico gets into the centrifuge

The olive oil was left in centrifuge at 3500 rpm for 20 min

Second step – Centrifuge. In order to remove the solid stuff both oils were left 20 minutes in a centrifuge rotating at 3500 rpm (rounds per minute). We could also make our life easier and just filter the oil. This method was discarded since I could not find a filter with certification that its influence on aromas and flavors is minimal.

The centrifugation was successful since both oils became transparent and the deposit was formed on the bottom of the container. Then, the oils were carefully decanted using a pipette. The picture below demonstrates how the cloudiness has disappeared in both oils.

The second and the fourth bottle contain the oils after centrifugation.

The second and the fourth bottle contain the oils after centrifugation.

Third step – Comparison. The aroma of the cloudy “Buža” oil had some unpleasant vegetal notes, similar to freshly cut green grass. The oil was either too young, or the olives, before they entered into the mill, were not cleaned from the leafs carefully enough. The vegetable notes practically disappeared after the centrifugation, and excellent notes of white flowers, radicchio and nuts came to the surface.

The aroma of the cloudy “Leccino” oil was very fruity, notes of green apple were obvious with hints of aromatic herbs and dry hay. The centrifugation practically did not change the aromas of this oil. Maybe there was only a very slight loss in intensity of herbal (green) aromas which caused that fruity (sweet) aromas became more perceptible.

Both for the “Buža” oil and for the “Leccino” oil, I did not notice any change in quality and intensity of flavor after the centrifugation – they remained equally spicy and slightly bitter.

In conclusion, the molecules responsible for intense aromas and flavors are (mostly) not residing in the solid particles that makes a young oil cloudy. The plant material is responsible for “green” vegetal aroma that is not always pleasant. Instead, molecules of other aromas are dissolved in the oil.

There is a big problem with the plant material floating in the oil. In two or three months it will deposit on the bottom of bottle, it will start to rot which will lead to deterioration of aroma and taste of the oil. Technically speaking, it will acquire “muddy” flavor characteristics.

So, what an olive oil producer should do to protect his oil from deterioration?

An industrial scale centrifuge that runs at 3500 rpm would be a very expensive toy for a small olive oil producer. Filtering the oil through carefully chosen filters could give equally satisfactory results. But (yes, there is always a but) according to this article

(appart from the plant material)… on the same time, cloudy olive oil contains microdroplets of vegetative and non-vegetative water in small amounts (0.1-0.3%) forming an oil/water emulsion. This unique physicochemical state of cloudy olive oil maybe responsible for the observed increased oxidative stability of that type of oil compared to the filtered one. Cloudy olive oil has higher levels of polyphenols, or polar phenols that form a complex polyphenol-proteincomplex. This complex interacts within the suspension/emulsion system and contributes to the formation and maintenance of the physicochemical properties of this oil.”

Unfortunately, any filtering will remove these microdroplets of water in which polyphenols (responsible for high antioxidant activity) and other molecules responsible for aroma and taste may be dissolved.

Fortunately, if your olive mill has a very good centrifuge, you don’t even have to filter it. It will be enough to wait one or two month, the plant material will naturally deposit on the bottom of container, you decant the oil and that’s it. Your oil will be crystal clear.

If such transparent olive oil is kept under the atmosphere of a noble gas, I believe it is possible to keep its original wild and intense aromas and flavors and good polyphenols concentration for a while longer – at least a year.

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{ 5 comments… read them below or add one }

Olivera November 24, 2009 at 13:57

Bok! Jako ti je zanimljiv ovaj blog, cijeli tekst odiše oduševljenjem i ponosom za vaš vlastiti maslinik i maslinovo ulje (ne sumnjam da je odlično!). A i pokus ti je zanimljiv (samo ne znam koju metodu senzorske analize si primijenio i tko su ti bili panelisti :). Centrifugiranje bi ipak trebalo imati prednosti pred filtracijom, jer celulozni filtar ipak upija nešto tvari arome. Inače, prije godinu i pol panel USAMU radio je senzoriku za doktorat jedne kolegice: ocijenili smo 6 sortnih ulja od kojih je svako bilo u dvije varijante (tj. filtrirano i nefiltrirano). Filtracija je provedena propuštanjem ulja kroz sloj vate. Može se reći da se tvoji rezultati podudaraju s našima, naime, filtrirana ulja bila su u pravilu nešto jačeg intenziteta mirisa po voću i zdravom plodu masline, te nešto više gorka. Još te samo želim upoziriti da pojam “flavor” ne podrazumijeva samo okus već cjelinu okusno-mirisnih svojstava, gorko i (uvjetno) pikantno su okusna svojstva tj. bilo bi ispravnije za njih koristiti izraz “taste”.

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Gogo November 25, 2009 at 01:14

eksperiment sam napravio čisto iz zabave tako da je senzorska analiza daleko od one prave. ja i kolega smo naizmjence mirisali čas mutno, čas iztaloženo ulje u cilju da vidimo kako se mijenja intenzitet i kvaliteta mirisa. intenzitet je više manje ostao isti dok miris izgubio travnate note i okrenuo se prema slađem voćnom. znači i vi ste to primjetili? nakon toga smo ih kušali, ali neku razliku u okusu nismo uspjeli zamijetiti.

sad u Vodnjanu su me dosta razočarali “veliki” maslinari jer je većina već filtrirala ulje pod izlikom da to moraju prije buteljiranja. na taj način su ga ukrotili i to više nije imalo tako intenzivne i kompleksne mirise kao što ga mlado ulje treba imati. kod nekih se čak blaga nota po plastici osjetila, vjerojatno jer filter nije bio dobro pripremljen. zato su me oduševili “mali” maslinari koji ulje nisu filtrirali nego samo pretočili kad se istaložilo, i bilo mi je gušt vidjeti kako ta stara metoda daje bolje rezultate od brutalnog filtriranja. i tvoj kolega prof. Lancanto Conte iz Udina, kada sam ga pitao kada filtrati, kaže da bi se što manje mirisa i okusa izgubilo bilo bi poželjno ulje samo pretakati do siječnja, a tek onda ga filtrirati. isto kaže da je grijeh mlado ulje filtrirati jer mu se odmah uklone većina polifenola koji su svi topivi u vodi.

na kraju, tko zna da li je moguće filtrirati samo organsku materiju a ostaviti polifenole i molekule zaslužne za miris i okus? zvuči kao pravi zadatak za nanotehnologiju 🙂

hvala za savjet za flavor, ja sam se vodio terminologijom koja se koristi kod vina gdje je aroma=miris a flavor=taste=okus.

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Carlos November 26, 2009 at 06:40

There is an explanation for “cloudy olive oil” in Wikipedia:
http://en.wikipedia.org/wiki/Cloudy_olive_oil

Apparently you are right, it’s a suspension’ of plant material in the olive oil. The cloudy oil is richer in polyphenols, a natural antioxidant responsible for longer shelf life, health benefits and contributor to the bitter taste (that some consumers love!).

Thank you for the wonderful story of making your own olive oil.

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Gogo November 26, 2009 at 12:03

Carlos,
Thank you for the article in Wikipedia. So, in cloudy olive oil apart plant material that is floating, there are also microdroplets of vegetative water in which polyphenols are dissolved. Plant material is bad because it is of organic origin and it will start to rot and ruin your oil.
If you filter the oil, you will remove both plant material and microdroplets.
A problem that remains to be resolved is – how to design a filter that removes only plant material but leaves precious polyphenols and aroma/taste molecules in the oil.
Nanotechnology?

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Nefretiti January 12, 2010 at 17:13

Super clanak. Imala bih par pitanja za tebe vezano uz ulja. Ajd mi se javi mailom ako stignes. Thanks

Bye

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