Extra-Virgin Olive Oil: Influences On Flavor

October 12, 2015
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hand picking olives

By Alexandra Devarenne

Beautiful to look at, a delight on the palate and good for your health, extra-virgin olive oil has become a staple of every food enthusiast’s kitchen. After decades of thinking first of Italy when olive oil was mentioned, Americans are broadening their culinary horizons to include extra-virgin olive oil made in California.

Olives are harvested in the fall and winter. Good olive oil requires good fruit, properly handled. Olives begin to deteriorate as soon as they are picked so it is critical that the fruit be processed promptly.

Production systems and harvest methods vary. Traditional spacing, seen in older olive groves, widely spaces trees to allow dry farming. These are harvested by hand or with limb shakers. Medium density doubles the number of trees per acre and uses irrigation to produce higher yields. These can be hand harvested or machine harvested with shakers. Super-high-density (SHD) production puts the trees in a compact hedge-like configuration to accommodate over-the-row harvesters.

At the mill, the fruit is cleaned of leaves and twigs, and washed if necessary. Olives are ground to a paste, pits and all, using a hammer mill or occasionally a disc or stone mill. The paste then goes into a tank to be gently warmed and slowly stirred for an average of 30 to 45 minutes in malaxation. During this process biochemical activity creates aromatic compounds and the oil begins to separate. In the decanter, centrifugal force is used to separate the oil from the solids and fruit water. A final spin in a vertical separator polishes the oil, removing the last olive particles and water. The term “first cold press” is still used by some for marketing reasons—many consumers mistakenly seek the term—but hydraulic presses are obsolete.

Unique among major food oils, olive oil is ready to use straight off the mill. The season’s new oil—the cloudy, spicy, wildly fresh-tasting olio nuovo or novello—is eagerly awaited in all olive oil producing regions. Poured liberally over grilled bread, legumes, soups, stews, pasta, rice or whatever is at hand, it is one of the quintessential flavors of autumn. Many a Thanksgiving dinner is now built around the olio nuovo alongside our other seasonal bounty.

There are many influences on the style of an olive oil. As with wine, the variety of olive used is a big determinant, but unlike grapes, olives can be harvested at many different degrees of ripeness. All olives start green, and become black as they ripen. When harvested early, the olives will tend to yield more peppery (aka pungent) and bitter oils with green fruity notes like grass, artichoke, green olive, herbs or spice. As the fruit matures, riper flavors emerge, such as nutty, almond, ripe olive or tropical notes.

Variety and maturity work together in olive oil style. Some varieties are intrinsically higher in the polyphenols that contribute pungency and bitterness. Growing conditions and processing also impact the style to a lesser degree.

California grows olive varieties from around the world. Note: that is olive varieties. Not varietals. Although the wine world got this one wrong years ago, the olive oil world is fighting to correctly use the term varietal where it belongs; we use olive varieties to make varietal oils.

These are some varieties being grown in California for olive oil.

Arbequina—from Northern Spain, this variety is the most planted oil olive in California, almost always grown in SHD (Koroneiki and Arbosana are the other two main varieties that can be grown in this system). The traditional style in Spain is a later harvest, very fruity oil with tropical and almond notes, but it is used to create a wide range of oils with greener notes and distinct pungency but low bitterness.

Frantoio—from Italy, Frantoio is widely planted in California. It is a mainstay of the “Tuscan blend,” an intense green-style oil. Frantoio is very fruity and aromatic, and depending on harvest maturity, flavors range from fresh-cut grass and artichoke to floral and nutty, with moderate bitterness and pungency.

Koroneiki—the main oil olive in Greece but widely planted around California in SHD groves, this variety has a distinctive flavor of green banana, grass and herbs when harvested early, and 
riper banana notes with a later harvest. High polyphenols make the oil bitter and pungent when green and contribute to good stability.

Mission—California’s original olive, brought by the Franciscan missionaries from Mexico, and planted alongside the missions up the coast. It is a dual-purpose table and oil olive. The oil can be intensely bitter when green, with notes of pine and resinous herbs. With a later harvest it becomes buttery and mild, with tropical fruit/pineapple flavors.

Ascolana (Ascolano)—an Italian variety traditionally grown for table olives, Ascolana has risen to fame in recent years in California as an oil olive. The flavor is distinctive, herbaceous with notes of apricot/peach and a nutty finish.

Coratina—the major variety in Southern Italy and gaining importance in California. Coratina produces a range of flavors from grassy and artichoke to cherry, depending on harvest ripeness. Famous for its abundant polyphenols, it has high bitterness when green.

Leccino—this is another cultivar that originated in Italy but is popular in California. Modest polyphenol content allows for an early harvest oil that is full of cinnamon, grassy, green almond, nutty and buttery notes with light bitterness and medium pungency. Leccino is another component of the “Tuscan” blend.

Picual—this is the most important cultivar in Spain and has started to gain hold in California. It was dissed for years because it is common in cheap, poorly made commodity olive oil, but well-made early-harvest Picual produces an excellent aromatic oil with tomato leaf and subtle tropical notes, and balanced bitterness and pungency.

Extra-virgin olive oil is truly a magical ingredient in the kitchen. With complexity to rival wine, it invites exploration and experimentation. Seize the chance this harvest to visit a local producer and enjoy the power of the new oil to elevate and transform food at your holiday table! 

Olive Oil Mill Tastings and Tours


California’s oldest olive oil maker (since 1936) now with the fourth generation working in the business. Gift Shop & Tasting Room are open Monday through Friday 8am–5pm. Modesto, CA SunshineInABottle.com

McEvoy Ranch

A pioneer in the California olive oil renaissance. Tastings and tours are available Wednesday through Saturday by appointment. Petaluma, CA Organic farm shop in Ferry Building open seven days a week. McEvoyRanch.com


The Olivina is a historical ranch growing and milling olives. Tastings by appointment. Livermore, CA TheOlivina.com

Il Fiorello

Located outside Fairfield, this newly remodeled tasting room/event center hosts cooking classes and other events. Olive grove and mill are onsite. Tastings are available 1–5pm ($5 with food pairing included). Fairfield, CA IlFiorello.com

Séka Hills

Located within a small grove of olives, the beautiful tasting room has a viewing window into the mill so you can watch the action. Other local foods are available in the deli/shop; open Wednesday through Sunday 11am¬–6pm. Brooks, CA SekaHills.com

The Olive Press

Sonoma Valley’s oldest and award-winning olive mill. The Sonoma location has a viewing window into the milling room. Open daily 10am–5:30pm. Sonoma, CA Oxbow Market: Napa tasting room and retail store open Monday through Saturday 9am–7pm, Sunday 9am–6pm TheOlivePress.com

Alexandra Kicenik Devarenne is an international olive oil consultant and educator based in Sonoma County. She is the author of Olive Oil: A Field Guide from AOCS Press. 

Article from Edible Silicon Valley at http://ediblesiliconvalley.ediblecommunities.com/food-thought/extra-virgin-olive-oil-influences-flavor
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