Olive Oil Primer
June 9, 2011
A comprehensive guide for confused consumers . . .
Confession: I am old enough to remember the days when olive oil was considered exotic in Toronto. Once, at the home of an Italian school buddy, we ate popcorn popped in olive oil. It seemed so strange, I still recall the taste and smell.
The Italians and Toronto’s other olive oil-loving immigrants got it right. It’s a versatile oil, not just for cooking but for dressing, drizzling, dipping – even baking. (Baked goods made with olive oil stay moister and have a longer shelf life.) It’s a healthier oil, too, full of antioxidants including polyphenols, tocopherols (vitamin E) and carotenoids. Oleic acid, a monounsaturated omega-9 fatty acid, is predominant in olive oil.
Olive oil is recognized as a mainstay of the Mediterranean diet. Its advocates don’t skimp on it. In Crete, where they boast of being the largest per capita consumers of olive oil and the healthiest population in the world, the food is swimming in it.
So yes, today, olive oil is no longer viewed as “foreign” or “ethnic.” It’s in a lot of different kitchens. Nevertheless, consumers are still confused about what to buy.
I knew less about olive oil than I thought I did when I flew to Crete during harvest season last December. Local members of the International Olive Council had invited me, as part of a group of global journalists, to tour the island and learn about olive oil production. When I got home, I continued to dip into the subject. This guide is my way to pay it all forward.
The most basic of basics: the label should say “extra virgin,” or if you’re less fussy, “virgin.” The closer to raw, the better the oil. Virgin oil is basically pressed, raw olive juice.
Although some would disagree, I say there is no point buying bastardized olive oil. Refining bastardizes olive oil. Heat and chemicals not only neutralize defects and excess acidity, they strip oil of flavour and antioxidants.
An exception: if you want to deep-fry, reach for a refined olive, seed or vegetable oil. Virgin olive oil has a lower smoke point, meaning it breaks down at lower temperatures.
The Acid Test
When olive oil lovers get together, the first thing they talk about is the acidity. Checking acidity is the fastest, easiest way to assess quality. It’s not the be all and end all, but it is a good start.
Acidity refers to the content of oleic acid and other fatty acids – the lower, the better. Extra virgin olive oil should have acidity no higher than 0.8%. Premium olive oils go even lower. Once an oil is in the realm of, say, 0.3%, its maker will loudly and proudly proclaim it on the label.
There’s a lot behind these simple percentages. If you read between the lines, acidity will speak to you about the quality of the olives and production methods. Were the olives roughly harvested or stored too long? Were they damaged by pests or fungus? Was too much heat applied before pressing? Was the oil overexposed to heat, light or air? Is the oil breaking down due to old age? All result in rising acidity.
A Matter of Taste
Looking at a number is one thing. Smelling and tasting is another. The latter is known in the olive oil business as “organoleptic assessment.”
Yes, there is such a thing as a professional olive oil taster. Tasters get together in panels of 8 to 12 to rate olive oils on a sliding scale. They judge positive qualities in three categories (fruitiness, bitterness and pungency), take note of defects and describe flavour nuances. It is as serious a business as wine tasting, with similar techniques.
Want to do like the professionals do?
Make sure you sample oil at room temperature. It’s best to use a small glass that curves in slightly at the top. If you are testing several oils, cover the glasses with little plates. Clear your palate between each oil with a bite of coarse bread or tart apple, followed by a gulp of water. Professionals drink the oil straight. If you can’t bear the idea, dip a chunk of rustic bread into the oil instead.
Assertive oils are highly rated. For instance, “persistence,” or how long the flavour remains in your mouth, gets high marks. Ironically, qualities prized in top olive oils can be disconcerting. Many North American consumers are used to reaching for the mildest supermarket brands. Top olive oils can be a hard sell, not only because of their price but because of their boldness. Consumers used to mellowness are apt to relegate distinctive premium oils to the realm of acquired tastes, or even confuse positive characteristics with defects.
Fruitiness refers to vibrant olive flavour. It is described as either “green” or “ripe.” On the tree, olives turn from green to purplish brown to black. They can be harvested and pressed at any time during this ripening cycle. Neither “green” nor “ripe” is better, just different.
Bitterness can be a turn-off for North American consumers. Some bitterness, however, is desirable. Fresher oil is more bitter. So is oil from green olives. Both these qualities are in turn linked to the presence of healthful polyphenols (antioxidants). Bitterness is an important part of the oil’s flavour balance. But overpowering bitterness is a sign that unripe olives with little meat on them have been pressed. In that case, bitterness is listed as a defect.
Pungency gives an olive oil pizzazz. The best oils go down smoothly, then the pungency sneaks up on you. You may feel a tingling in your throat or a scratchy sensation. The oil may even elicit a sharp little cough. Italians call this pizzante and cherish it. Pungency varies. Oil made from younger green olives is more pungent.
Defects are olive oil horror stories. There is no debate about them. They are black and white; they exist or they don’t. They do range in intensity. Oils that lose their distinctive character, taste and aroma are condemned as “impersonal.” At the opposite end of the scale is the catch-all defect called “lampantino,” used to describe a pressing that is good only as lamp oil. With modern production techniques, some defects have become rare. The two most common defects are rancidity and fustiness. The most wide-ranging are vinegary and muddy qualities.
• Brine: Salty. Oil pressed from brined olives.
What colour should your olive oil be? This one is tricky.
Olives mature from green to black. In between, they turn a colour called “veraison.” (Veraison is a term borrowed from the wine-making world, described as purple-red, but olives at this stage look more purplish brown to me.) Olive oils in turn range in hue from green to gold. Besides ripeness, olive variety, terroir and even production procedures influence an oil’s colour.
A bit of science: the actual pigmentation depends on the proportions of chlorophylls (green), carotenoids (yellow-reds) and pheophytins (chemically altered chlorophylls, appearing grayish-green).
Green olives are harvested when they have reached normal size, but have not yet turned colour. They contain more chlorophyll, so they yield greenish oil. Greener oil is sassy and peppery.
But is your oil green for the right reasons? Inevitably, some leaves end up being crushed with the olives. Occasionally, however, oil producers cheat – deliberately leaving greenery on the olives or even adding leaves to an olive batch. This creates a greener oil with a greener flavour (called “grassiness”).
Almost or fully ripe black olives have more carotenoids, so they yield a golden oil. Milder and fruitier, this is what marketers consider an “entry olive oil” for inexperienced consumers.
But is your oil golden for the right reasons? As oil sits, ages and spoils, it loses its greenness and turns yellow. That’s why I look for a slight green sheen, no matter what the base colour of the oil.
I’ll talk about proper storage later, but it’s interesting to note that pigments can affect freshness. In the presence of light, chlorophylls and pheophytins promote the formation of destructive free radicals and speed up oxidation. Thus the oil goes bad faster. In the dark, however, chlorophyll acts as an antioxidant. Thus the oil keeps longer. Theoretically, a green oil with more chlorophyll, kept in the dark, will last the longest.
Going to the Source
Today’s olive oil buyers can pluck their purchases from a vast array of different brands at different prices. So what do they do when they are uncertain? Go out and buy something Italian. Olive oil and Italy have become synonymous in popular culture. Who can forget the legitimate arm of the Corleone movie family, the Genco Pura olive oil importing business?
The truth is, olive oil is produced around the globe – not only in the Mediterranean, but in places as far-flung as New Zealand and California. And the world’s largest producer by far is Spain. Italy comes second, followed by Greece. To keep up with massive production levels, biggies may import pressed oil to blend and call their own.
Another truth: they make good and bad olive oil everywhere. For instance, the Mediterranean countries produce some fabulous, prize-winning oils, but it is also estimated that more than half the olive oil produced there is so bad it must be refined. Also, corruption and poor inspection practices in some countries mean you may not be getting the extra virgin oil you pay for. Past scandals range from lesser quality oil being sold as extra virgin to olive oil being adulterated with inedible oils.
So country of origin is not a reliable factor. It's better to consider specific brands and production methods.
How It’s Done
The process of making virgin olive oil is similar around the world. Here are the basic steps:
If you were a picky consumer walking along a production line, here are some questions you might ask:
Are the olives from one grove, one commune, one region?
What olive variety was used?
When were the olives picked?
Green olives are harder, thus more difficult to press. Oil from green olives tastes grassy and somewhat bitter, which many aficionados appreciate. Oil made from fully ripe black olives is sweet, with no pungency or bitterness. Ripe olives hold the most oil, but require more care. Because they are soft, they are easily damaged and more difficult to mill, which can affect oil quality.
In health terms, oil from green olives has the highest level of antioxidants and the longest shelf life. However, this advantage is counteracted somewhat by the fact the paste has to be mixed longer (malaxation), which increases oxidation. Polyphenol levels peak on the verge of veraison, then begin to decline. Oil from black olives has the least antioxidants and the shortest shelf life.
When were the olives pressed?
How modern is the mill?
Some pros: Modern equipment creates the flavour consistency so important to maintaining a brand. It’s more sanitary, too. Keeping absorbent pressing mats impeccably clean is impossible, so they eventually taint fresh batches of oil. Centrifuges expose the paste/oil to less oxygen, thus preserving antioxidants.
Some cons: Hammer crushers and centrifugal force bring out more bitterness and pungency in oil. Techniques used to increase oil yield – heating the paste, adding water to the paste or again to the pomace (residue), increasing malaxation time – strip healthful polyphenols.
Is the oil cold pressed?
Once upon a time, using older equipment, it was impossible to squeeze most of the oil from the paste at first go. To extract more oil, hot water was added to the leftover pomace and the mixture was pressed again – and again. Of course, these subsequent pressings were inferior. Hence the prestige of the term “first press.”
The “cold” part is still important, though. A product is no longer considered virgin if the paste or oil has been exposed to excessive heat. What is excessive? Let’s say no warmer than 27C (80F).
The industry is moving toward the term “cold extracted.” A label that says “cold extracted” is referring to virgin oil, filtered or centrifuged, exposed to temperatures no higher than 27C (80F). A label that says “first cold pressed” is referring to virgin oil, extracted using hydraulic presses and mats, exposed to temperatures no higher than 27C (80F).
Was talc used?
Here’s how it works: Talc is an inert mineral, meaning it doesn’t react chemically with olive paste or oil. It does react physically with it. During crushing and malaxation, talc prevents and breaks up emulsions or globules of oil and water trapped together. It also clumps oil droplets into larger drops. Thus, more oil can be extracted.
Is the oil traceable?
Sadly, North Americans are used to rancid olive oil, and they don’t even know it.
Here’s how olive oil goes bad: It oxidizes. Oxidation is a chemical and enzymatic reaction between the oil and oxygen. Exposure to air or light, and of course, simple aging give it impetus. Sunlight and artificial lights in the plant, store or your home help speed up the reaction between the oil and oxygen. If no air is getting into the container, oxidation still occurs, albeit much more slowly. In this case, free radicals related to oxygen react with the oil. Antioxidants in the oil absorb these free radicals, but once they are used up, the oil goes rancid quickly.
Nothing good can come of oxidation. Healthful polyphenols are depleted and peroxides are created. Besides marring the flavour and odour of the oil, peroxides destroy essential fatty acids and fat-soluble vitamins.
The message: Protect virgin oil from exposure to light and air. Don't bounce it between extremes of heat and cold. Use it up before it suffers from the indignities of old age. Some experts cite a shelf life of two or more years, but the oil is best consumed within 12 to 18 months after bottling. Look for best-before dates, or better still, harvest/bottling dates on the container. Seal it tightly, not only to keep it fresh but because it absorbs odours easily.
What type of container should you buy? First, think small. Whatever container you choose, make it the smallest size that’s convenient. That way, you avoid long storage times at home.
Like wines, olive oils come in a variety of containers. Tetra and plastic bag-in-box formats are the latest thing. Both help block out light and air. Stainless steel cans do, too. (Tin or reactive metals are beyond consideration.)
Good old glass, however, is the best. It is the most inert material. This means it doesn’t react with the oil, so few or no chemical compounds are created or transferred. To block light, the glass should be as dark as possible. Black is best. Consumers, however, are resistant to black bottles. They want to see the oil. So most virgin oils are bottled in tinted glass. Avoid anything in clear glass.
Note where and how the container is stored at the shop. And store the oil carefully when you get it home. Keep it in a cool, dark spot, away from windows, radiators or even heat from the oven. Optimal temperature range: 8C (46F) to 16C (61F), with 10C (50F) being the ideal in terms of reducing oxidation but not turning cloudy from the cold.
Forget the fridge or freezer. People do argue that refrigerating or freezing virgin olive oil does no harm or even prolongs its life. When returned to room temperature, however, it is prone to condensation.
Because it turns sludgy in the fridge, virgin oil may be mistaken for a saturated fat. (Not so. Saturated fats are solid at room temperature.) In the cold, fatty acids and natural waxes from the olive fruit congeal. You may see crystals, clumps, small blobs or pearls, or a slimy egg white effect in the oil. It may look mouldy. Years ago, I kept tossing out refrigerated dressings made with olive oil, thinking they had spoiled. Some oils thicken more than others. If an oil shows no reaction to the cold, it may have been “winterized,” which involves removing waxes.
In the freezer, virgin oil sets, unlike refined seed oils. If your virgin olive oil doesn’t harden in the freezer, be suspicious.
Most countries follow the classifications set by the International Olive Council. The IOC governs 95 per cent of international olive oil production. It defines olive oil as:
Virgin Olive Oil
Virgin oil is obtained solely by mechanical means, without excessive heat that alters its chemical structure, and is untreated except for washing, decanting, centrifugation and filtration. There are four grades.
Anything from defective virgin oil to lampante may be refined. Refining strips flavour and antioxidants. It also strips defects. Refined oil has a longer shelf life and higher smoke point (meaning it can reach higher temperatures before breaking down). It is light in flavour and colour, and may be labelled “light” or “lite.”
How is olive oil refined? With the use of high heat and filters (chemical or physical, such as charcoal). But unlike other refined oils, no solvents are allowed.
An aside: Most vegetable/seed oils (such as soy, corn and canola) are extracted using food-grade hexane, a petroleum byproduct. Hexane is a solvent, meaning the oil dissolves in it. The bad news: it is toxic in small amounts. The good news: it boils at a very low temperature so it can be removed from the finished oil under conditions of low heat and vacuum. Once hexane is used, chemical refining, bleaching and deodorizing is necessary. Techniques include water washing with alkali such as lye or caustic soda; bleaching with clay; filtering with diatomaceous earth (fine, porous rock with silica), activated carbon or synthetic silica; deodorizing with active carbon; steaming under vacuum. These methods remove substances ranging from free fatty acids to pesticides, and reduce pigments such as chlorophylls and carotenoids.
Pomace is the pulp left after the olive paste is pressed or centrifuged. It includes skins, pits and stems, and looks dark and somewhat dry. After the first extraction, about 5% of the oil remains in this residue. The remaining oil can be extracted once high heat and solvents are applied to the pomace, but altering the fatty acids is a no-no. Technically, pomace oil cannot be called olive oil.
The Americans are doing their own thing. In 2010, the U.S. Department of Agriculture set new olive oil standards, similar to those of the IOC. The catch: they are voluntary. Producers pay the USDA for certification. However, the USDA says a product may be labelled olive oil without any certification as long as the claim is truthful. This contributes to consumer confusion about olive oil. Can you be sure of what you are buying?
Virgin Olive Oil
You’ve got it in one. Couldn't have put it better.
-- by Carajean on 2011-06-23 13:24:28
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