Acidity, quality, taste, essence and color of olive oil depends on climate, characteristics of field, soil fertility, variety of olive, tree care, olive pests, status of pest struggle, type of fertilizer, methods of harvesting and transportation, time elapsed from harvesting to the processing, washing of olive, mashing techniques.
Usually a well equipped laboratory is not a must for the measurement of the acidity of an olive oil sample. Following equipment is adequate for this purpose: a glass pipette, a glass measuring cylinder, and a glass balloon. Chemical substances: some volume of alcohol ether and acidity detection solution, obtainable from any pharmacy…
First, draw a sample from the oil using a metal cup specially designed for that purpose. Introduce 10 gr of oil into glass measuring cylinder. Introduce 30 gr of alcohol ether and add it to the oil and mix well. On the other hand, draw olive oil acidity detection solutions into pipette and adjust the decimal indicator to zero. Place the balloon under the pipette. Open the switch of the pipette, allow some solution drop and close the switch. Drop the solution until the mixture in the balloon become red permanently.
Check the pipette, indicator is at 1 s dizyem; as ı O dizyem indicates one acid, the acidity of this oil is one and half. Keep in the mind that oil with superior quality become red rapidly. Oil with high acidity becomes red later, i.e. as in the “Lampant” or “Soap” oil.
Among the other things, bear in the mind that the color of the pure oil starts to become cloudy at 10°C, rapidly coagulates at +5° - +4°C and solidifies at from 0° to -6°C. Solidified oil dissolves in the room temperature. Following traditional examination method used by some of the old experienced tradesmen purchasing olive oil in Edremit; draw samples from various oil cans, put them in a metal plate, prepare a wool wick, burn the wicks simultaneously; check which wick burned longer and with lesser smoke, showing the highest quality olive oil. Wick in the fine olive oil with low acidity burns longer than the defected olive oil with high acidity.
All extra virgin olive oils with an acidity rate below one and close to zero are of course superior oils. But nonetheless they can show variation in color, essence and taste, according to the region, geography, climate, early or late harvesting, even year to year.
Taste of olive oil
It is important to determine the quality of virgin olive oils. The initial step is the measurement of the acidity of these oils, which can be done by chemical analyses. However, low acidity should not be considered as the sole indication for the quality of oil; essence, color and taste parameters are also of another major importance; because, pure olive oil firstly appeals to our sensations. Organolpetic sensations, including color, taste, odor is the business of experts. Experts determine whether the oil with a specific acidity fits to extra virgin oil standards or not. But, if the essence of oil is not good, there is no need to check its color or taste.
Organoleptic examination method
Tasting or “organoleptic examination” of olive oil is an art, but it can also be fun and worth learning, which requires a certain amount of knowledge and quite lot of practice to objectively classify oils. According to IOOC an expert should avoid smoking or the use of perfumes, deodorants, perfumed soaps and lipstick, eat sweets or drink coffee within 30 minutes before or during the tasting. No problem for those who do not smoke, but smokers are obliged to follow some rules. Moreover, they should avoid eating something for 1 hour before the examination. In other words, they should keep their mouths and stomachs empty, during this 1 hour period. An expert should be dismissed from the examination if he/she suffers from flu, fever or other serious disease or a physiological distress problem, which would cause confusion during tasting.
Expert examiner expresses his/her determinations with reference to negative or positive attributes or uses quality scoring over 5 to 10, during the determination of color, flavor and essence, namely of the “organoleptic” characters of an olive oil. If there is a next sample to taste, he/she should chew a piece of apple to previous oil taste from his/her mouth.
For organolpetic examination of virgin cooking oils, previously prepared “taste profile forms” are used. “Taste intensity” is scored on a scale from 0 to 10, according to negative and positive parameters. Negative and positive parameters used by the expert during organoleptic examination of color, taste, or essence of an olive and noted down to a “taste profile form” for a coded sample are as follows:
Negative parameters: Musty, moist; moldy, vinegarish- winey, acidic- sour, turbid, metallic, rancid. “Other” includes following parameters: burnt-wood, massive/intense- metallic oil-olive-mill wastewater-salty (brine olive press taste) – sour (sour taste from dirty pressing bag) - earthy- wormy cucumber taste. “Tasting intensity” of a sample determined according to negative parameters should not exceed 2.5 in a 1-10 scale. If exceeds, this oil is not acceptable.
Positive parameters: Opposite to negative parameters “taste intensity” increase is a desired thing, which is in an indication of the superiority of the quality of oil. In other words, negative parameters “eliminate” the oil; on the other hand positive parameters such as fruity taste (freshness), bitter, sharp (passing of oil from throat) “elevates” the oil.
Organoleptic sense panel
In order to determine the highest quality oil, a “degustation” or “organoleptic taste panel” is established. 15 ml samples are drawn from oils in the glasses, they are ordered from intense to light ones, and put in front of the experts sitting in different cabinets or away from each other. The identity, quality and varieties of oils, coded with letters or numbers are only known by the head expert. These oils should be kept at 28oC for the best organoleptic examination. Averages of personal assessments of each expert are calculated for each oil sample. The oil(s) with the highest score will be “the best oil(s)”. In brief; the best virgin olive oils are the ones with least negative parameter scores, while with high positive parameter score. Olives with high negative parameters, with low testing intensity will be regarded as low quality olives.
Examination by non expert persons
Of course you, those trusting their tongue and nose, can do it amateur at your homes. How? Briefly; First of all keep in your mind that it is difficult for your taste organ to recognize more than a there or four oil varieties. Therefore, for the beginning do not exceed 4 or 5 samples. Another clue, you should at the beginning taste the “fruity”, namely “olive taste” oils. Draw sample from oil and put into glasses coded with number or letters, you should not know the identity or the quality of the oils to be tasted. Then take one of these glasses and put your hand on it and rotate the glass to wet the sides fully; warm the sides of the glass with the palms of your hands to liberate the volatile aromas; bring the oil as closely as possible to your nose and inhale slowly and deeply two or three times in succession, note your findings about its aroma, if necessary, repeat after about a minute. Than take a small sip of oil in your mouth.
Keep in your mind that different areas on the tongue, palate and throat involve in the perception of the primary tastes. Therefore, in order to determine the taste and intensity of the oil properly you should distribute the oil throughout the whole of your mouth cavity, including the apex and center and back of your tongue as well your teeth and palate. Finally drink the oil sample slowly; here, you should take “viscosity” of the oil sample into account, namely the “intensity” of the oil. Meanwhile, with your lips semi-closed inhale rapidly two or three times in succession to atomize the oil and enable the taste molecules penetrate all relevant regions of your mouth.
How did you find the fist oil sample sir? Did you like its taste and essence? For example what kind of flavors it associates? Apple, green pepper, almond or walnut? Musty or grass? You can realize the aforesaid taste parameters samples. Finally note down your scores on a paper.
It will be better to use a special assessment chart. For example, in a chart designed according to International Olive Oil Council (IOOC), you can check your assessment in the column designated for the corresponding parameter, choir, taste, color, essence, and score them over 5. (5: perfect, 4: very good 3: good, 2: medium, 1: poor)
Before tasting the next oil sample, you should clean your mouth as a professional expert to the taste of the previous one. How? A slice of apple is adequate. For some, a piece of bread is better, which is not true. Because bread ferment will slightly change the real taste of the oil, as well remaining starch between your teeth will lead you confuse the intensity of the oil.
Than collect the scores you gave for each sample, check the one with highest result, it is the best oil. For example, in the previous paragraph the score 4 refers to a high quality oil. But bear in mind that, the best oil is not considered among high quality oils. If the oils examined conforms the quality standards every oils are good. Namely, no best oil but the good and bad oil. The rest is to your pleasure.
Furthermore, as quality cheese, quality oil is to your pleasure. For the rest, your job is not quality expert. But an other exam method you may try at your homes maybe useful in practice: As in the past as our olds were cooking the rice before buying one bag of rice, you can try a virgin oil recommended to you at your homes; how does it for green salad, eggplant and potatoes salad? How mush does it improve the taste of the table olive, what flavor does it give with fish? Light or intense essence? Light or intense taste? What result does it yield with boiled squash, eggplant or grebe beans, or as a macaroni sauce? Conclusion: the oil fitting your pleasure best is the best quality oil...