Olive Oil Questions:

2/8/2008 - Mary Asks: Just wondering if the olive oil my mother used in the 30s and 40s was the original "virgin" olive oil -- when did the use of machinery/processess begin which made the oil "non-virgin"????

Olive Oil News responds: Your premise has a romantic nostalgia but is faulty. Most of the olive oil made throughout history would nowadays be considered non-virgin. Olive oil was a valuable source of calories and not a fancy condiment. People didn't really care much how it tasted. The olives were often collected off the ground after they had partially fermented. There were no insecticides so olive grubs were the norm. The olives were heaped in piles on the dirt where they continued to decay. They were then ground in a circular trough with a hard to clean stone wheel at ground level in close proximity with a hard-working donkey going in circles. Before it could be pressed the paste was spread on mats made from grass or reeds which could not really be cleaned from day to day or even season to season. Boiling water was often poured on the paste to get more oil out. The resulting unfiltered oil from the lever or screw press was kept in pottery storage jars with loose fitting lids in a hot climate. In the few places where oil is still made "the old fashioned way" it tastes pretty disgusting. Read Olives: The Life and Lore of a Noble Fruitby Mort Rosenblum for some great stories about tasting olive oil in Northern Africa. In Imperia, Italy there is a great museum devoted to olives and olive oil, called Museo dell' Olivo. which show the old but unsanitary ways olive oil was made.

Starting about 100 years ago with the introduction of hydraulic presses and then centrifugal extraction units and clarifiers the oil started improving. Steel containers kept out air during storage and glass and tin containers kept the oil from oxidizing during transport to the consumer. Virgin olive oil was more a reality. Bad tasting Olive oil made the old fashioned way from less developed countries was collected, sent to processing facilities in Europe and treated with steam and solvents to make refined olive oil. It wasn't virgin but it was at least palatable.

Today the olives often go straight from the tree to the processing plant in the same day. The oil is made in scrupulously cleaned stainless steel machines with careful control of temperature and oxidation. Stringent laws regulate every kind of food processing plant. It is no accident that today far more olives are turned into virgin olive oil than at any time in the past as virgin and extra virgin olive oil commands a much higher price and profit.



12/14/2007 - milan: Why do olives need to be cured especially in the awful salt. Can they be preserved in another way?

Olive Oil News responds: Curing removes bitter components that otherwise make an olive inedible. Curing can be done with water, lye or salt.

But once the olive is cured it must be preserved or it can develop dangerous bacteria such as botulism.

Drying, salting and vinegar are the basic ways foods have been preserved from spoiling for thousands of years. Freezing and irradiation are two newer but less used ways food can be preserved.



12/3/2007 - N : For many years now I have used olive oil. I bake with it and fry with it. I use it to fry my donuts. I use it in my deep fryer. But someone told my husband that using it in your deep fryer is poisonous, which I had a hard time believing but it kept bugging me so I finally took the time to look it up so I could be convinced I was right. Thank Goodness. By the way many people commented on the good taste of the fries. When the oil gets dirty I just throw it away and add new. ( I buy Kirkland Signature at Costco) Do you know if it is processed properly and those kinds of things?

Olive Oil News responds: I'm glad you did not fall for the urban myth about frying with olive oil, it flies in the face of common sense considering that olive oil has been used for frying for thousands of years, long before there were such things as canola and corn oil.

As to the question about the Costco oil, label laws in the US do not conform to international standards so it is hard to know if an olive oil labeled as extra virgin is actually high quality. One plus is that large chains like Costco which private label their oil have more to lose if the product is found to be defective than if another brand they sell is involved in a scandal. I have seen the Kirkland olive oil brand used informally in several olive oil tastings here in California and it was found to have good taste for the price.

The small amount of olive oil made in the US and marked with the COOC seal has been extensively tested and is genuinely high quality.



11/5/2007 - Desiree: Your reader Gary said he could not find a certain olive oil taste he had found in Portugal. I am also a huge fan of Portuguese olive oil. During my travels there, I was told that the Portuguese let the olives sit for 10 days before pressing, which gives the oil its unique pungency and flavor. Is this true?

Olive Oil News responds: Each country has their own unique varieties of olive which contribute to regional olive oil flavors. Portugal has the Cobrancosa and Verdeal for example (see varieties) But letting olives sit after harvest will cause the fruit to heat up, spoil and ferment. The resultant oil will have high acidity and taste defects such as "fusty, musty, moldy, rancid". The oil would not qualify as extra virgin under current International Olive Council testing.

In most of the world in the past 2000 years processing capacity did not keep up with the harvest so olives sat and fermented. The traditional lever or screw olive press with reed mats was difficult to keep clean and encouraged oxidation and off tastes. Clay storage containers of the day were poorly sealed and oil quickly went rancid if it was not already. Oil was not an expensive condiment but a necessary source of calories so consumers were resigned to the taste and came to expect and prefer this traditional taste of the oil. In some parts of the world they still do. Mort Rosenblum in his book Olives, The Life and Lore of a Noble Fruit has a great story about traveling to a tiny town in North Africa where with great reverence he was offered a bottle of very musty rancid oil which the locals treasured.

In the past 50 years there has been a big improvement in olive oil processing, storage and distribution. If a producer can process the olives quickly in enclosed centrifugal centrifuges, store the oil in modern containers such as stainless steel, and prevent exposure to light and heat during distribution, the oil will be of higher quality and the price much higher. No modern producer would deliberately let their olives sit for 10 days if there was any way to prevent it.

I am hoping that the flavor your prefer is that of the unique Portuguese varietals. The Portuguese do not have a powerful marketing lobby so sell most of their oil to consolidators in Italy or Spain where it is blended with other oil. If it is the musty olive taste you are after, that is fine, as they say, "it is a matter of taste" and some people will prefer a flavor that others label a defect. Of course there is not a big export market for defective oil so you are not likely to see it in mainstream markets.

11/5/2007 - Rira: In olive oil,when Oleic acid in triglycerid place in mid position,its benefits on health(Cardiovascular Disease,etc)is more than when Oleic acid place in the two other sides?

Dr. Deane responds: The fats (triglycerides) in food are made up of a glycerol with three fatty acids attached. There are many different types of fatty acids such as oleic acid, linoleic acid, etc. They are like three flags flying on the glycerol flagpole. You seem to be alluding to the fact that different flags can fly in different order from up to down on the pole. But this should make no difference because in your intestine lipase enzymes and bile acids break down the glycerol and fatty acids, destroying the order. The glycerol and fatty acids pass into the intestinal lining cells separately. These cells then reform the triglyceride stringing the fatty acid "flags" on the glycerol "flagpole" in on order to their liking.

11/5/2007 - CN: I am seeking a natural remedy for a skin disorder which plagues my body. I have what the doctor biopsied and called eczema. So…eczema is my infliction and it is ugly. The subscribed medication is a gel base with a cortisone additive. I feel like I am always greasy and worry about the impact of so much cortisone.

Dr Deane responds: Moisturizers can be an important part of treating eczema. Many types of natural oils have been used successfully for eczema, such as coal tar, and vegetable oils like olive oil. It wouldn't hurt to try olive oil. Steroid anti-inflammatory creams work best for most people. Don't confuse the minimal long term effects of steroids used on the skin compared to the major side effects of steroids taken by mouth. Unless you are using the steroid cream over extensive areas of the body, you are absorbing little of it. For more, see
The American Academy of Dermatologists - Moisturizing for eczema
The American Academy of Dermatologists - Diet for eczema

10/22/2007 - Dolores: How long should be the life of a bottle of Extra virgin olive oil? How long should you keep it? I bought a large bottle at Sam's club a couple of years ago, and still have a little left, but afraid it might be too old....Does it turn rancid or lose it's flavor after a certain length of time? I just threw out a smaller bottle that had a date on it...best if used before Feb of 07....Should all bottles of oil have a expiration date on them....I am afraid to buy a large bottle again...please advise.

Olive Oil News responds: Shelf life is very variable, depending on the olive variety, ripeness when pressed, care in processing, filtering, etc. It also depends on storage after it has left the producer, something they have no control of, so it is hard to "guarantee" a certain lifespan. Look on the label for a date. Remember that most olives are picked in the late fall or winter and are sold the next year, so 2006 oil will be the freshest available until early 2008 when 2007 oil will come on the market.

Lifespan can be as little as 3 months for an unfiltered late harvest olive bottled in clear glass and sold off a supermarket shelf above hot deli foods which is then stored by the consumer in bright light on a hot stovetop with the cap unscrewed. It can be as much as 3-4 years for an early harvest, high polyphenol containing olive variety which has been filtered then packaged in a well sealed tin or dark bottle then stored in a cool dark place by the grocer and consumer.

Best to buy small quantities, use up the oil within 6 months.

Any vegetable oil will go rancid with time. The oil is still edible but will taste bad.

Click for a more lengthy discussion about olive oil storage



10/18/2007 - A Reader: I have heard that eating Olive Oil will interfere with absorption of vitamins and minerals

Dr. Deane: Fat soluble vitamins A,D, E and K are found in fatty foods. Some seed and fish oils are particularly high in vitamins. (See Nutrition for information about vitamins in olive oil.) If olive oil were to "soak up" fat soluble vitamins in the stomach from a pill or other foods, the vitamins would still end up in the body; the oil is absorbed into the gut to the blood stream and from there to all of the cells.

This misconception may have come from the use of Mineral oil as a laxative. Mineral oil cannot be absorbed by the body so goes completely through the GI tract, keeping the stool soft on the way out. If you were to take a fish oil capsule with your mineral oil, the fat soluble vitamins would be absorbed and trapped by the mineral oil and excreted.

10/18/2007 - Sky Radio 100.4 FM Athens, Greece: Are California producers importing seedlings from Greece?

Olive Oil News responds: Import law regarding live plants can be very restrictive. Generally the seedlings must have washed roots with no soil which could harbor pests. That means they must travel by air due to their fragility. Once planted, state law may require that they stay in quarantine for months to years. It is easier to buy Greek varieties from a nursery in California which has gone through this process and has then propagated the cuttings here. See Tree sources for nurseries selling Greek varieties. Try searching on Kalamata.

9/16/2007 - Trevor: Can I use olive oil to oil our wooden book shelves. They are made from salvaged tropical wood. We live in a cold and dry climate (in Canada), and were told to oil them twice a year.

Olive Oil News responds: Volatile oils will evaporate in a few days or weeks, "fixed" oils are more resistant to evaporation. Most vegetable cooking oils are classified as fixed oils. However, if you set out a container of most cooking oils, it would partially evaporate very slowly over months to years leaving a sticky varnish. You can see this varnish on the sides of pots and baking pans where the process has been speeded up by heat. A colorless, odorless cheap refined olive oil would probably work but the smell as it slowly oxidizes on your bookshelf and goes rancid may be potent. Linseed oil is a favorite vegetable oil for wood and much cheaper than olive oil and generally colorless. I would stick with the advice of a paint professional and keep the olive oil in the kitchen.