What Einstein Kept Under His Hat: Secrets of Science in the Kitchen (21 page)
Read What Einstein Kept Under His Hat: Secrets of Science in the Kitchen Online
Authors: Robert L. Wolke
Which brings us back to your question. (Remember your question?) By the time olive oil has been filtered, purified, decolorized, and practically de-olived to make light olive oil, most of its most flavorful, aromatic, and healthful compounds are gone. So rather than using an oil that has been stripped of its olive-ness, be a sport and experiment with the wide variety of olive oils on the market until you find your one or two favorites. Choose based on one and only one criterion: what you like.
Some chefs and cooks believe it’s a waste of a good drinking wine to use it in cooking. Others say that if it’s not good enough to drink, it’s not good enough to cook with. Similarly, conflicting advice abounds on whether a good, extra-virgin olive oil is wasted by using it to sauté or fry. Except for deep-frying, I prefer extra-virgin oil, both in cooking and on the table. For deep-frying in olive oil (Americans don’t do that very much, but Spaniards do), I use a good virgin oil. If you do too, try to find out from a specialty store or from the brand’s website the name of the predominant variety of olives that went into the oil. Spanish
picual
oil is reputed to be exceptionally stable at high frying temperatures.
Keep your olive oil ever within reach—but not too near the stove. Heat deteriorates all cooking oils and olive oil in particular, because its high percentage of unsaturated fatty acids is more susceptible to oxidation than are the saturated fatty acids of many other vegetable oils.
Like heat, light too is an enemy of olive and other vegetable oils. That’s why most olive oil bottles are green or smoky colored. You’ve read a million times (including a few pages ago in this book) that you should keep oils in “a cool, dark place,” but there’s no need to go overboard. “Cool and dark” doesn’t mean inside a refrigerator whose door is never opened lest its interior light go on.
“Cool” is a relative term, best interpreted as “not warm.” Nor does “dark” mean pitch-black. The high-energy ultraviolet rays in sunlight are what do the damage, so by all means keep your oil out of direct sunshine. Incandescent lighting doesn’t contain enough ultraviolet light to worry about, unless your kitchen is as bright as an operating theater. Fluorescent fixtures, however, do emit a substantial amount of ultraviolet light and should not be too near your oil-dispensing station.
THE FOODIE’S FICTIONARY:
Carotene—an adolescent carrot
Sidebar Science:
Fatty acid chains
THE NUMBERS
in parentheses in the middle column of Table 3 on page 178 are shorthand for the molecular structures of the fatty acids. The first number (16, 18, 20) is the number of carbon atoms in the molecule’s chain. The number following the colon is the number of double bonds (see “Kinky molecules,” p. 169) in the molecule; 0 indicates a saturated molecule, 1 indicates a monounsaturated molecule, and 2 or higher indicates a polyunsaturated molecule. For example, the monounsaturated FA molecule oleic acid (18:1), stretched out, would look like this, where O indicates an oxygen atom:
Note in Table 3 that almost 80 percent of the fatty acids in olive oil are monounsaturated and almost 10 percent are polyunsaturated. This high level of unsaturation has been linked to the healthful effects of olive oil. However, bear in mind the wide variation in types of olive oils. The percentage of saturated fatty acids in olive oils can range from 8 to 26, monounsaturated from 53 to 87, and polyunsaturated from 3 to 22.
Besides fats, olive oils contain other healthful chemicals in small amounts. Among the antioxidants are polyphenols; tocopherols, including vitamin E; and beta carotene, which manufactures vitamin A in the body.
The good-fat, bad-fat follies have been in continual ferment for the past few decades, so I won’t venture out onto any limbs that may crack off before you read this. Nevertheless, at this writing, it’s safe to say that saturated and trans fatty acids (see p. 169) are the bad guys, while unsaturated (mainly monounsaturated) fatty acids are the good guys. Stay tuned.
| | Citrus Brioche Loaf | |
M
ay the brioche police forgive me, but this loaf is made with olive oil instead of butter. It is scented with the zest of orange and lemon and bakes up airy and flavorful.
Many recipes for brioche call for double risings of the dough and a rest overnight in the refrigerator. This version is quick and easy to mix in the food processor with no overnight rise. It can also be stirred together conventionally in a large bowl. It is not kneaded. Bake the brioche in a loaf pan if you want even slices, or use a fluted pan to give the classic brioche shape. Serve plain or toasted with sweet butter and jam, such as the Strawberry Preserves on page 190. Day-old brioche makes excellent French toast or bread pudding.
1
1
/
2
teaspoons active dry yeast
3
tablespoons warm whole milk
1
/
4
cup sugar
2
cups all-purpose flour
3
large eggs, at room temperature
Grated zest of 1 orange
Grated zest of 1 lemon
3
/
4
teaspoon salt
6
tablespoons mild (not “light”) extra-virgin olive oil
1.
Lightly oil a 9-by-3-inch loaf pan or a 4
1
/
2
-cup fluted brioche mold, or spray with nonstick cooking spray.
2.
Sprinkle the yeast over the bottom of a food processor work bowl and add the warm milk along with a small pinch of the sugar,
1
/
3
cup of the flour, and 1 egg. Pulse 8 to 10 times, or until the mixture, or starter, is creamy. Scrape down the sides of the work bowl.
3.
Put the remaining flour on top of this starter, but do not mix it in. Cover the work bowl with the top of the food processor. Allow the mixture to stand until you can see that the starter has begun to foam and that the yeast is activated. Depending on the conditions in your kitchen, it can take from 15 minutes to 1 hour.
4.
Add the remaining 2 eggs, the remaining sugar, the salt, and the orange and lemon zests to the work bowl of the processor. Turn the machine on and whirl for 10 to 15 seconds, or until the dough comes together to form a ball. Leave the machine on, and pour the olive oil in a fine stream through the feed tube. The stream should be fine enough so that the ball will not lose its shape as you pour. The movement of the ball of dough around the edge of the work bowl will incorporate the oil into the dough. The dough is fairly forgiving. It will be sticky, wet, and creamy.
5.
Spoon and scrape the dough into the loaf pan or brioche mold. The pan will be about one-third full. Although a topknot is traditional on individual brioches, it gets in the way of slicing on a larger loaf such as this one. I prefer to leave it off.
6.
Allow the dough to rise almost to the top of the pan. Depending on the temperature of the kitchen, this can take from 1 to 2 hours. The risen, leavened dough will be very light and about three times its original volume. Preheat the oven to 375°F about 15 minutes before the dough is ready.
7.
Bake the brioche for about 30 minutes, or until golden brown.
8.
Remove the loaf from the oven. Allow to rest in the pan on a wire rack for 5 minutes, then turn out onto the rack and let cool completely before slicing.
MAKES 1 LOAF
Substituting olive oil for butter in baking
Olive oil can be substituted for butter in many breads and desserts. But because butter is only about 80 percent fat, you must use less olive oil. No other modifications are necessary. Here’s how to substitute. (Some of the amounts have been rounded off but are accurate enough in light of the fact that butter varies in its water content.)
BUTTER | OLIVE OIL |
1 teaspoon ( | 3 |
1 tablespoon ( | 2 |
2 tablespoons (1 oz.) | 1 |
1 | 3 tablespoons |
1 | 1 |
1 | 1 |
2 | 1 |
3 | 1 |
1 cup (8 oz.) | 3 |
Source: Bertolli Lucca
| | OLIVE-GREEN, OR OLIVE-BLACK? | |
For years I had been told that olives are green or black depending on when they were picked. Then a friend who had lived in California told me that they were picked at the same time but processed in different ways. Which is true?
....
L
iving in California doesn’t make a person an expert, except perhaps in surrealistic politics. But just as in politics, there is some truth in both your positions.
Olives are unusual sources of oil, in that almost all other vegetable oils reside in the fruits’ seeds, whereas in olives the oil is in the flesh.
As olives ripen, their colors change from straw-colored to green, purple, and, finally, black. The transformation from green to black takes place over a period of about 3 to 4 months. So you win the first round; olives may be picked at any one of these stages (except when they are straw-colored), depending on their destiny, whether for oil or for eating at the table. (“May olives be eaten with the fingers?” “No, the fingers should be eaten separately.”—Henry Morgan.) Purplish olives generally produce better-quality oil than fully ripe black ones.
But your victory may be as hollow as a pitted olive, because some “black” or “ripe” California olives are picked at the purple stage and then blackened by treatment with alkali, air, or iron compounds (see below) to produce what are called “black-ripe” olives.
The olives on a tree don’t all ripen at the same time, so there is always a mixture of stages to be harvested. Perhaps the biggest problem faced by olive growers is deciding exactly when to harvest for the best yield of the best stage of ripeness for the olives’ intended purpose. Over the years, different countries and regions have developed and maintained their traditional harvesting practices, which contribute to the different flavor characteristics of, for example, Greek and Italian oils and even oils from different regions of Italy.
Historically—and by that I mean for thousands, not hundreds, of years—olives have been harvested by hand, either individually plucked or by means of a sort of comb known as a
pettine
(which is Italian for, well, “comb”) that is raked along the branches. Alternatively, workers may simply beat the branches with poles to dislodge the fruit. Hand-harvesting is still widely used today, although in Spain, the world’s largest producer of olive oil (a lot of olive oil labeled “Italian” is shipped from Spain and bottled in Italy), I saw heavy, tractor-like machines clamp strangleholds on tree trunks and shake the bejeebers out of them, the ripest and less tenacious olives falling into nets placed on the ground around the tree.
For table use, all olives must be processed in some way; you can’t snack on them right off the tree because they contain a bitter phenolic compound called oleuropein. It must be removed either by microbial fermentation or by soaking in a strongly alkaline solution such as sodium hydroxide (lye).
In California, semi-ripe, greenish-purple olives are soaked in a series of lye solutions of diminishing concentrations, being rinsed and aerated after each soak. This treatment, aided in some cases by the addition of ferrous gluconate, an iron compound, turns the olives thoroughly black, after which they are canned.