Grades of Olive Oil
Extraction of Virgin Olive Oil
A green olive is simply one that has been harvested before it has fully ripened.
Selection of olives for oil is critical to the oil’s final quality. Pitfalls include use of olives that are too ripe, or that have been oxidising too long after harvest (ideally, they should pressed almost immediately). Thereafter they are washed and crushed (including pips and skins) into a
Extra Virgin Olive Oil
Extra Virgin Oil is the natural, unprocessed oil extracted from the first pressing of the olives. The level of free fatty acids (“FFA’s”) (read “degree of rancidity”) thereof when packed may not, by definition, exceed 0.8%.
We blend oils from a number of Western Cape estates, and also from Spain. We offer the oil in a range of sizes from 250 ml, to 1000 lt.
Virgin Olive Oil.
If olives had lain in the sun after harvesting for full, hot day in April (Southern Hemisphere), the FFA of same may be, say, 1.1% – still palatable, but poor quality. The oil would be from the Virgin pressing, but would lose the “Extra” denomination. If the FFA exceeds 1.5% it may not be called “Virgin” oil. Oils with a FFA exceeding 0.5% are generally refined into….
“Pure” Olive Oil, or “Light” Olive Oil
After refining, this oil is neutral, and some virgin oil (maybe 3%) is added back to augment the flavour. Expect to pay nearly an Extra Virgin price for “Pure” olive oil. Demand is high because it has the favourable fat profile of olive oil but is less prone to rancidity on the shelf. Its stability is favoured by manufacturers who wish to add the oil to foreign material like cured olives or infusions of herbs. Our view is that these oils are processed, and are no better than,say, commercial canola oil.
These oils have a low FFA.. about 0.01%.
The price of this by-product is further augmented because inferior virgin oil (read “suitable for refining”) is increasingly scarce. Olives are not allowed to lie around much awaiting processing in the 21st century!
Pomace Olive Oil (aka “Sansa” or “Aruja”)
Olive presses are unable to extract a residual 4% olive oil from the olive pulp. A process of “hexane extraction” is able to chemically extract most of this residue. To restore food-grade quality, it has to be refined, whereafter some extra virgin olive oil (about 3%) is added to give it some flavour. Because it has in the past been cheaper than the abovementioned oils, it’s been favoured by soapmakers. There’s an international shortage nowadays, and it’s price is close to that of extra virgin olive oil.
Some pizza establishments dip some wood in pomace before burning the wood in the pizza oven .. it imparts a pleasing aroma to the room.
Notes regarding the colour of olive oil
The colour of Extra virgin oil (which may vary from “straw yellow” to deep green) isn’t an indicator of the quality thereof.
There are five possible reasons for variation in the colour of extra virgin olive oils;
- Different varietals of olives impart different colours
- Time of harvest. While olives from an earlier harvest will have a higher (green) chlorophyll component, those harvested later will have relatively more (yellow) carotenoids (see figure below).
- Adding olive leaves to the olive pulp at the pressing stage. This is at best cosmetic, and it can increase the harshness of the oil
- Addiition of copper chlorophyllate (I submit some Italian producers do this).
- Dipping the olives in hot water at the pressing or malaxing stages The figure below, as applied to the Manzanilla varietal illustrates this (source; http://amandabaileyonolives.com.au/).
Another polemic; is extra virgin olive oil good for cooking?
Experts differ; imho it’s a no-brainer. It’s incorrect to heat a cold-pressed oil, thereby losing its subtle flavours and it’s health properties. It doesn’t make sense that the producer should compromise his yield by cold-pressing the oil, only to have Mr Philistine heat it! Further, the flavour of the resulting food is rich and undefined .. it will overpower the other ingredients.
Extra Virgin olive oil is best served cold on salads or directly onto a plate of food.
For cooking, we pioneered the concept of seed-oil blends (see “other products“) as a more stable (and cheaper!) option. I twigged on the idea when I was delivering extra virgin olive oil (from my car boot!) to chefs in Cape Town. The chefs (yes, even the most prestigious ones!) were blending their extra virgin olive oil with seed oils. So I suppose it wasn’t my idea at all in the first place!
On origins of olive oil in South Africa
Much “Italian” oil is in fact imported into Italy in bulk, mostly from Spain.
My guess is that imports from the Mediterranean basin account for about 60% of our local consumption.
What does “Cold pressed” olive oil mean?
As an aside, almost all oil is in fact “centrifuged” rather than being “pressed” between stone wheels in this day and age.
A producer could improve his yield of oil when processing his olives by heating the pulp. In so doing, he would compromise the quality thereof. Polyphenols (read “subtle flavours”) would drop, and the free fatty acids (read “degree of rancidity”) would rise.
Olives typically yield between 14% and 18% of their weight to oil.
In practice, I’m not aware of local farmers heating their pulp. The threshold above which pulp should not be heated is, by convention, 30°C. That’s not much warmer than a warm April/autumn day during the harvest.
What’s that mean? (this isn’t codified anywhere, by the way). In my humble opinion the temperature of a quality extra virgin oil should NEVER have been more than 30°C (see my note on cooking with extra virgin olive oil above).
It could be argued that refining of a cold-pressed edible oil doesn’t alter the fact that it was “cold-pressed”. I’d dispute that. Because the process of refining oil involves heat, the oil loses its cold-pressed status – irrevocably
On age of, and storage of olive oil The saying runs “Old wine and young olive oil”. Freshness, typified by a smell of fresh-cut lawn, is everything. (I’ve yet to detect this freshness in an import). One can manage the triple threats of light exposure, oxidation, and temperature. – a tin is better than a dark green bottle is better than a clear bottle. Store in a dark place. – a sealed container is essential .. and once opened, finish the oil within a fortnight. A bottle made from PET (plastic) is just as impervious as one made from glass or from tin. – chill the oil (although it will solidify at <5°C, it will melt again without any problem)(experts differ on this recommendation) Bulk storage on the estates is in stainless steel tanks at 18°C, under a nitrogen blanket.
On subjective quality of extra virgin olive oil
I taste every incoming batch and decide how it’ll be used. We are committed to achieving consistent year-on-year quality.
If the oil shows any defective characteristic we don’t sell it as extra virgin.
I drew up this table to help me.
|Timing of cause of problem||Problem||Cause||Description of off-note|
|Before Pressing||Mouldy||Mould on olives||Dusty, Musty|
|Fermented||Fermentation (anaerobic)||"Fusty", sweaty socks, swampy vegetation|
|After Pressing||Rancid||Oxidised||Crayons, putty, or rancid nuts. Greasy mouth feel.|
I look for
1) Straightforward notes (ie not complex; ripeness of input olives should not vary too much)
2) Freshness (should smell like a newly-cut lawn).
3) Robustness (preferred varietals are coratina, leccino, FS17). These varietals offer a bitter and peppery oil.
The Spanish Picual qualifies on point 3), but performs poorly on point 2).
Certain varietals are more suitable for table olives (eg Mission, Manzanilla, and Kalamata). We seldom use oil pressed from these varietals.