My colleagues and I are set to crush tons of olives and taste lots of extra virgin olive oil over the next several weeks during our harvest. And one myth I like to clear up at this time of year is the idea that an olive oil’s color is a reliable indicator of quality. Wrong!
“Don’t pay much attention to the color of an oil. Good oils come in all shades, from vivid green to gold to pale straw,” olive oil aficionado Tom Mueller writes in his excellent book, Extra Virginity.
Flavor and aroma are better gauges of quality. In other words, smell and taste the oil. Mueller notes “genuine extra virgin oils have a marked fruitiness reminiscent of fresh olives, and typically some level of bitterness and pepperiness.”
That’s why professional tasters use colored glasses when sampling olive oils: They want to avoid a “color bias.”
That said, color will tell you other things about an olive oil, like when the olives were harvested. “Olives picked early in the season tend to make green colored oil as they contain higher levels of chlorophyll,” Australian olive oil guru Richard Gawel writes in an FAQ.
“Olives harvested late in the season will typically produce more golden colored oils due to a higher level of natural occurring levels of carotene-like substances. Both oils may be technically equivalent in quality but very different in style.”
What influences flavor? Like wine, the particular olive variety – i.e., Arbequina, Arbosana, etc. – influences an oil’s flavor. Ditto for soil conditions and weather. When the olives are harvested also plays a role. Early-harvest oils tend to have “grassier” flavors, while late-harvest oils tend to have “buttery” notes.
Flavor is one of the reasons we rush our olives to the mill after picking them. The shorter the gap between harvest and milling, the more likely the oil will have the kind of fresh flavor Tom Mueller describes.
How the oil is stored also is important. Avoid exposure to heat, light, or oxygen – all promote oxidation and can make an oil rancid. That’s why we bottle our oils in dark green bottles – to protect them from light.