Marlene Parrish - What Einstein Told His Cook 2

Raw garlic and onions have little or no aroma until cutting or chewing breaks open their cells. An enzyme and another preexisting chemical (a precursor ) that had until then been isolated from each other can now meet and react chemically to produce the odorous and sharply flavored compounds we know too well.

But in hot water these seven-syllable chemicals ( alkylthiosulfonates ) change into other polysyllabic compounds: propyl and propenyl di-and tri-sulfides and thiophenes. These are among the compounds that give flavor to our garlic and onion soups.

And frying? Don’t ask. Dozens of other chemicals are produced at the high temperatures involved, notably the many aromatic, flavorful, and bitter compounds created by the Maillard browning reactions. (See Chapter 7.)

Let’s look at what happens to onions as we subject them to more and more aggressive cooking techniques. Garlic behaves in very much the same way.

Dried, raw onions are made up of about 37 percent sugars and 8 percent proteins, so they brown predominantly by the Maillard, or sugar–amino acid, reactions. Yet virtually every chef refers to the browning of onions in a skillet as “caramelizing” them. Perhaps a reason for that can be found by examining the three different stages in the cooking of this uniquely flavored vegetable: sweating, goldenizing (I’ll explain), and frying.

Sweating:We sweat raw onions by placing them diced or sliced in a sauté pan with a little bit of butter or oil, covering the pan with a circle of parchment or waxed paper (or a cover), and cooking them slowly over very low heat. The heat vaporizes some of the water inside the onion’s cells (onions are 89 percent water). The vapor pressure bursts them and releases their juices, in which the onions then simmer and steam. They turn soft and translucent (another consequence of the broken-down cell structure), but we stop cooking them before any browning takes place. The initial pungent flavor compounds will have been converted to the softer-flavored compounds we associate with onion soup.

Goldenizing:If instead we cook the onions uncovered, the released cell juices will quickly boil off and the temperature will rise from around 212°F (100°C) to perhaps 300°F (149°C), where the Maillard browning reactions proceed rapidly. The fact that some of the Maillard products are sweet is perhaps one reason that cooks are enticed into using the sugar word caramelize for this process. What they really mean, however, is taking the onions only to a soft, golden tan—the color of caramel candies—but stopping short of actually browning them.

In hopes of banishing the use of the word caramelizing for the gentle sautéing of onions, I hereby offer to the world the word goldenizing . I realize that goldenize has only three syllables to caramelize ’s four (and for heaven’s sake, people, it’s CAR-a-mel-ize, not CARM-el-ize), but what it may lack in grandeur it more than makes up for in accurate imagery.

Frying:If we continue cooking beyond that stage, Monsieur Maillard really goes to town and we wind up with honest-to-goodness fried onions, with their intense “browned” flavors.

So goldenize your onions to a pleasing russet hue and a mild, sweet flavor. But you’re not caramelizing them unless you’re one of those people who add a little bit of sugar to hasten the production of color.

May I never again hear or read about “caramelizing” onions or, for that matter, “caramelizing” any other foods that cook up brown. Except sugar.

Note: I know full well that I am fighting a losing battle. No matter what this chemist guy says, chefs will continue to talk about “caramelized” onions, “caramelized” grilled meats, “caramelized” fond in the bottom of a sauté pan, and “caramelized” anything else that turns brown when cooked. But I tried, and that makes me feel better. The Great Chemist in the Sky will bless me for it.

Sidebar Science: How much garlic?

WHEN THE CELLSof a garlic clove are broken open by slicing, crushing, or chewing, an enzyme ( alliinase ) in the cell vacuoles spills out and reacts with a precursor compound ( alliin ) in another part of the cell to form diallylthiosulfinate ( allicin ) and other thiosulfinates, which are the main odoriferous and flavor compounds. Until relatively recently—1993—it was thought that the odorous compounds were diallyl disulfide and other polysulfides, but it has been shown that these were merely the breakdown products of thiosulfinates, and were inadvertently created in the analytical laboratory by the high-temperature methods being used. (A scientific research principle: Always make sure that your analysis procedure isn’t changing what you’re trying to analyze.)

Thus, when garlic is cut into smaller and smaller pieces, or reduced even further by being crushed, more vacuoles are broken open, more alliinase enzyme is released, and more thiosulfinates are formed, producing a stronger aroma and flavor.

A similar sequence of events takes place in sliced and chopped onions, initiated by the same enzyme, alliinase, but producing somewhat different flavor and odor compounds. (See “The tear factor,” chapter 3).

So when a recipe specifies a paste from a garlic press, or slivers of cloves, or chopped garlic, pay attention; otherwise you may get more or less than you bargained for.

TRUE LOVE

I absolutely adore garlic and use it in all its forms: roasted whole heads or cloves, chopped, minced, crushed, or pressed, depending on the dish I’m making. But once in a while I’m stuck at the last minute for a touch of garlic flavor in an almost finished soup or stew or on Italian green beans, so I sprinkle on a little garlic powder. I know it’s frowned upon by gourmets, but emergencies are emergencies. What do you think?

Ishare your love of garlic. When my foodie wife, Marlene, and I first met for a blind coffee date, she didn’t ask about my religion, politics, or income. Practically her first question was “What do you think of garlic?”

Without hesitation I replied, “Garlic is the closest thing we have to proof of the existence of God.” And we have been cooking happily ever after.

First of all, garlic powder is not a good substitute for fresh garlic because in the process of being dried and powdered, garlic loses a great deal of its volatile flavors. But as you say, emergencies are emergencies. I won’t tell anybody if you don’t. (I use it on popcorn.)

Dried garlic was invented for the same reason as other dried spices and herbs: to preserve a perishable product. At the garlic-powder factories they first break the bulbs down into cloves, smash them, and blow away the papery skins. They then dry the naked cloves, remove any residual skin fragments, and powder the dried material. Much of our garlic powder comes from India and China, where both the raw garlic and the hand labor involved in processing it are relatively cheap.

But obviously, the fresh herb loses a lot of its “charm” in the process, so the dried and powdered product can’t hold a candle to the fresh.

BOTULISM IN A BOTTLE?

I’ve heard warnings about garlic-infused oil, but I never really got to the bottom of it. My question for you is: Is there any validity to the claims that garlic oil is dangerous?

We must be careful to distinguish between garlic oil , the intrinsic essential oil of the garlic plant, Allium sativum , and garlic-infused oil , an edible vegetable oil (usually olive oil) that has been flavored with garlic.

Pure garlic oil is indeed nasty stuff that is never ingested per se . One of its major ingredients is allyl trisulfide, a teaspoon of which in its pure form would kill half the people who swallowed it and burn the esophagus in the rest of them. But you could never eat enough garlic to come within miles of that amount, nor would anyone come within miles of you if you did.