Talk to chef Christian Graves about olive oil, and he gets almost giddy about the variety of oils he uses from around the world.
The average home cook might think one bottle in the pantry is plenty for everything from sauteing to making vinaigrettes, but Graves treats olive oil as a key ingredient in every dish he makes, selecting just the right style of oil to achieve the flavors and textures he’s looking for.
“Most chefs have their favorite brand,” said graves, of San Diego. “If I’m looking at a pasta with olive oil, I would look at it differently than sole with olive oil. With pasta, I would want to use something sharper. With fish, you don’t want to overpower it, so I would maybe look at those with grassy overtones.”
Grassy? In fact, that’s one of the most common adjectives describing extra-virgin olive oil, the highest grade oil due to its low acidity. Young green olives can also produce a bitter flavor —a good thing, as long as it’s not too bitter. There’s fruity olive oil. Buttery. Spicy. It can taste like artichokes or apples. Herbs or almonds.
As with wines, olive oils can have a wide range of flavor profiles, depending on the variety of olive crushed for the oil, the age of the olives when harvested and pressed, the soil the tree is grown in and the method of pressing — cold versus heat, centrifuge versus stone mill.
Different regions in the world produce distinctive flavors that tend to complement the region’s style of cooking. And because of this, no one olive oil goes with all foods.
Peggy Knickerbocker, author of “Olive Oil: From Tree to Table,” recalls the time she brought Spanish olive oil from Granada to a friend in Tuscany. “She tried it, but very kindly told me to take it home with me because it didn’t go with her food,” Knickerbocker says. “Tuscan oil goes with heavy, hearty Tuscan food.”
Of course, everyone does need a basic workhorse oil. For simple sautéing or frying, Knickerbocker turns to a consistent-tasting oil sold by Trader Joe’s, Martini’s Kalamata oil. “It’s cheap, and it tastes good,” she says. “I use it for cooking onions and garlic. Then I’ll finish the dish with a good artisanal oil.”
While the olives’ age and variety determines much of the flavor, how the oil is extracted from the fruit also contributes to flavor and can give you a good indication of its quality.
Both in the Mediterranean countries that produce oils and in California, where 600,000 gallons of oil is expected to be produced in 2009, olive-oil makers pride themselves on the techniques they use. The preferred method is cold press, meaning the oil is extracted without using heat, but there are different extraction methods even within cold press.
Large-scale producers such as California Olive Ranch use a hammer-mill crushing system that works like a meat grinder, using high speed and force to push olives through a screen.
“It evenly crushes the olives into a paste in a manner that allows continuous flow,” explains Alan Greene, the company’s vice president of business development and chairman of the California Olive Oil Council. “We can process 3.5 tons of olives an hour.”
The pulp is then pumped into a malaxor, which stirs it to distribute the water and oil. Then it goes into a horizontal centrifuge, where the water is thrown off and the oil is trapped and collected, to be pushed through a screen to catch more particles. Then the oil is cleaned in a vertical centrifuge, which spins at 6,000 rpm, and sent to stainless-steel tanks for storage.
At Temecula Olive Oil Company, an artisanal producer in Temecula, Calif., the process is a little different — more reminiscent of old-fashioned stone-mill pressing in Italy.
“We’re doing an updated version of the classic olive-oil press,” says owner Thom Curry. “I think it’s the best way to produce oil. It’s gentler and more authentic. It’s the way olives want to make oil.”
Instead of a hammer mill and centrifuge, Curry had two large, stainless-steel mills fabricated to crush the whole olives. (Traditionally, the mills are made of stone, but Curry was concerned about rancidity caused by the porous stones trapping the oil.)
The olives are poured into a large steel container, and the mills rhythmically circle around and, with a sound like rain on a tin roof, crush the olives into a tapenade-like mixture. This pulp is sent through another machine that presses it out to workers who push it onto steel-mesh mats that are then stacked onto a press. Gravity works the oil out of the mash like teardrops — what Curry calls “tears of gold.” The mixture still contains water, so it’s drained into separators and then stored.
Extra-virgin and virgin oils are extracted in the first press. The difference between the two is based on acidity. Extra-virgin has a free acidity of no more than 0.8 grams per 100 grams and has no flavor defects. Virgin olive oil is higher in acidity, with no more than 2 grams per 100, and may have some minor defects.
Second and third pressings, using heat or chemicals to extract more oil from the paste, produce pure, light and pomace oils. These refined oils are fit for consumption but won’t have the flavors of extra-virgin or even virgin oils.
In California, where the first olive trees were grown and harvested by Franciscan monks at Mission San Diego de Alcala around 1800, growers like Curry are testing different varieties of trees to find the right combination of olives to work with. Arbequinos and Missions are among the most popular.
According to COOC executive director Patricia Darragh, California has more than 125 varietals of olives. “That allows us to do single-variety or unusual blends,” she says.
Curry, for instance, has more than 35 varieties of trees and likes to combine the olives for pressing.
What is the optimum flavor profile? Darragh describes it as well-balanced. “It should have three attributes — fruit, bitter and pungent,” she says.
“It should smell and taste like olives. Unfortunately, a lot of Americans are used to consuming bottles that say extra-virgin but are really refined oil with a flat, neutral taste. Good olive oil has a fresh taste.”
2 cloves garlic
1 teaspoon kosher salt, or to taste
3/4 cup cooked fava beans
Grated zest from 4 lemons
1/4 cup Spanish extra-virgin olive oil
1 tablespoon finely grated parmesan cheese
1 tablespoon chopped mint
1 tablespoon chopped basil
Yields 1 cup.
Crush garlic with salt in a mortar and pestle (or combine in a blender). Add fava beans and mash to a fine paste. Add lemon zest and olive oil, and blend until emulsified. Add a little water if needed. When you achieve desired texture, stir in parmesan, mint and basil. Use as you would basil pesto, on pasta or steamed vegetables.
Nutritional analysis per 2-tablespoon serving: 80 calories, 7 g fat, 1 g protein, 3 g carbohydrates, 0.6 mg cholesterol, 258 mg sodium, 1 g dietary fiber.
— Chef Christian Graves