Part 3 (1/2)
First, imagine what would happen if water evaporated from the top of the souffle preparation. No swelling would take place. Thus the highest souffles will result from heating the ramekins from below. Put them directly on the lowest rack in a heated oven.
Second, the bubbles have to be trapped for them to be able to make the souffle rise. Thus the egg whites must be beaten into very firm peaks, so the bubbles will be trapped in the very firm foam.
Third, the increase in volume is diminished if the bubbles escape from the top. Thus allowing a crust to form on the top of the souffle, as proposed earlier, will promote successful rising.
To summarize, then: heat from below, use firmly beaten egg whites, and let a crust form on the top of the souffle.
Cooking The Secrets of Tenderness As mentioned earlier, in cooking we have three objectives: to kill harmful microorganisms that contaminate food, to change the consistency of foodstuffs, and to give them flavor. Often the cook achieves these ends simultaneously, because heat, which kills microorganisms, for example, also degrades meat's toughest molecules and triggers chemical reactions that engender aromatic compounds.
Why does cooking tenderize meat? Why does it make vegetables lose their rigidity? And, more generally, what is the secret of culinary transformations?
The culinary arts begin and end with the art of cooking, and it certainly isn't feasible to summarize the whole book in this one chapter; such an extraction would be too concentrated. I will only attempt a preliminary clarification, saving the various types of cooking for later chapters.
In every case, heat increases the mobility of atoms and molecules, which can thus react because they now have enough energy to be transformed. The molecules b.u.mp into one another, break apart, and, when chemical groups with some affinity come into random contact because of the erratic movement of the molecules, rearrangements take place. These rearrangements are called chemical reactions. They produce new compounds.
How Do We Heat Foods?
The question seems naive, but try, for example, to heat a thick soup by holding a small electric heater over its surface. The very top layer will boil, but the rest of the soup will remain cold. Likewise, a good roast on a spit must be done in front of the fire rather than directly over it. If you roast quail, the most delicate of birds, barded as it should be with grape leaves between the fat and the bird, you will get only the taste of smoke if you cook it directly over the fire. But if you know the mechanics of radiation and put the spit at the same height as the flame and beside it, your fowl will roast gently, through to the center, and the flesh will be delicately flavored with the subtle taste of grape leaves.
This is why it is especially useful to know that heat is transmitted to dishes through three mechanisms: conduction, convection, and radiation.
BILLIARD b.a.l.l.s IN THE SAUCEPAN.
Conduction is the phenomenon that occurs when a solid is heated. A metal spoon left in a boiling liquid will burn your fingers. Likewise, the heat conveyed by an oven to the surface of a roast, for example, is gradually transmitted to the molecules of the interior. In effect, the outside molecules, agitated by the heat, collide with molecules located deeper within and thus transmit their energy to them. Those molecules, colliding with molecules even closer to the center, pa.s.s along the activity and thus the heat.
Heat is the agitation of molecules. Foods are like heaps of billiard b.a.l.l.s. If you agitate the outer b.a.l.l.s, they will transmit their agitation to the adjacent b.a.l.l.s closer to the center of the heap, which will then transmit their energy to the b.a.l.l.s still closer to the center, and so on. This is the phenomenon of heating through conduction.
CONVECTION AND SKIMMING.
In liquids, it is convection that accelerates the transmission of heat. When a saucepan full of water is heated from the bottom, the water at the bottom heats first, through contact with the bottom of the pan, which is itself in contact with the stove. Naturally, the heat is transmitted through conduction, but beyond that, the hot water at the bottom, less dense than the cold water found above it, rises and is replaced by the cold water, which is then heated. The liquid currents, called convection currents, circulate in the liquid and rapidly distribute the heat.
This phenomenon is apparent when you skim a sauce. Say you are making a braised dish, for example. First you sear a piece of meat and its tr.i.m.m.i.n.gs in the oven (see the chapter on braising). After five minutes of searing, you add one-fourth of a liter (about a cup) of good white wine, cover the pan, and continue the cooking at a very low boil by lowering the oven temperature to between 60C (140F) and 100C (212F), depending on the coagulation point you desire. After an hour of this slow cooking, you combine half the liquid with a roux (made by cooking a little flour in b.u.t.ter until it is a pleasing golden color). The roux will thicken the liquid drawn from the meat pan. Skimming it will produce a sauce that is light, smooth, and satiny; the process must be slow and consistent. First, you tilt the saucepan to one side (by raising the opposite side with an object that does not mind the heat, like an old spoon). Heated in just one spot, the liquid forms a single convection cell that absorbs the heat from below at the point of contact, rises vertically and descends along the sides. This prompts the coagulation and aggregation of all the unwanted solid matter, which is returned to the center of the convection cell and forms a sc.u.m that can be regularly drawn off. At the same time, you dab the surface of the sauce with absorbent paper toweling to remove the fat that appears as unemulsified droplets. With this slow process, you allow the time for many chemical reactions to occur ... and to generate a wonderful flavor.
Convection was discovered by Count Rumford (Benjamin Thompson), an inspired adventurer who, among his many other scientific studies, pondered the question of why his applesauce remained hot long after his soup had cooled.23 We know now that convection is most active when the medium is least viscous. In a viscous medium, the liquid circulates with more difficulty. In the case of Rumford's thin soup, convection rapidly exchanged the heat of the bowl and the air, whereas the heat of the thick applesauce could escape only through conduction and thus slowly. So the sauce stayed hot longer than the soup. We know now that convection is most active when the medium is least viscous. In a viscous medium, the liquid circulates with more difficulty. In the case of Rumford's thin soup, convection rapidly exchanged the heat of the bowl and the air, whereas the heat of the thick applesauce could escape only through conduction and thus slowly. So the sauce stayed hot longer than the soup.
A LIGHT THAT COOKS.
The third method of heating involves radiant heat, which is what makes the front of you warm but leaves the rest of you cold when you are facing a fire. Heating through radiation is the principle behind roasting meat. A fire or a grill emits heat rays a.n.a.logous to light rays but invisible: infrared rays. Like light, they disperse in straight lines and are stopped by opaque bodies. When they are absorbed by meat, their energy heats and cooks it.
Cooking with microwaves, of course, is also a process of heating with radiation. But in that case the waves penetrate the foods in much the same way as light pa.s.ses through gla.s.s windows.
What Kind of Cooking for Which Dish?
Once the heat is in the food, it fulfills various functions that are all part of the cooking, among them, softening hard substances, coagulation, inflation or dissolution, transforming the appearance, reduction or extraction of juices or nutritional elements.
Convection, conduction, or radiation? The following a.n.a.lysis considers most of the cooking processes. The heating medium will generally be a fat, a liquid, dry air, or moist air.
When the heating medium is a hot solid, conduction produces a grilled dish.When the heating medium is hot liquid fat, convection and conduction produce a sauteed dish if the food is simply lying in the fat.When the heating medium is hot liquid fat, convection and conduction produce a deep-fried dish when the food is immersed in the fat.When the heating medium is warm liquid fat, convection and conduction produce such wonderful dishes as confits.When the heating medium is a boiling liquid, convection and conduction produce a boiled dish.When the heating medium is a simmering liquid, convection and conduction produce a poached dish.When the heating medium is steam, convection produces a steamed or braised dish.When the heating medium is moist air, convection is responsible for the cooking of oven roasts.When the heating medium is dry air, radiation is responsible for roasting foods on a spit.
Keeping in mind that ”The discovery of a new dish does more for human happiness than the discovery of a star” (Brillat-Savarin),24 let us not forget microwaves, which cook in a unique fas.h.i.+on. Radiation is absorbed by certain molecules within the food (water molecules), and the heat of these molecules then cooks the entire food by being transmitted through conduction to the molecules unaffected by microwave radiation. let us not forget microwaves, which cook in a unique fas.h.i.+on. Radiation is absorbed by certain molecules within the food (water molecules), and the heat of these molecules then cooks the entire food by being transmitted through conduction to the molecules unaffected by microwave radiation.
Cooking Without Heat?
No list of cooking processes would be complete if it failed to mention one slightly peculiar process: cooking with chemicals.
Do not be frightened by the name. Cooking with acids, for example, is simply a matter of placing foodstuffs in lemon juice or vinegar. In these two cases, the liquid, an acid, is responsible for making the proteins coagulate. That is how fish left in lemon juice is transformed, just as if it had been poached in boiling water, although its flavor is very distinctive.
The Boiled and the Bouillon Fifty Hams!
For a long time, meat was believed to be made up of two parts: the part that pa.s.sed into the bouillon when meat was cooked in water for a long time and the fibrous part, which was called le bouilli le bouilli, or the boiled. Gourmands did not have words harsh enough for le bouilli le bouilli. Stripped of its succulent elements, boiled meat no longer deserved a place on their tables.
Brillat-Savarin relates the following anecdote in honor of the ”osmazome,” which was supposed to be the princ.i.p.al component of taste in meats: The Prince of Soubise planned to give a great party one time; it was to end with a supper, and he asked for the menu.His steward appeared at his morning conference with a handsomely decorated sheet of paper, and the first notation the prince's eyes fell upon was this: fifty hams fifty hams.”Look here, Bertrand,” he said, ”it seems to me you are dreaming! Fifty hams! Are you trying to treat my whole regiment?””Not at all, sir! Only one ham will appear on the table, but the rest are essential for my sauce espagnole sauce espagnole, my white sauces, my garnishes, my ...””Bertrand, you're thieving from me, and I shan't let you get away with it.””Ah, my lord,” the artist said, hardly able to hold back his wrath, ”you know very little of our resources! Command me, and I can put these fifty hams which seem to bother you into a gla.s.s bottle no bigger than your thumb!”What was there to say to such a positive a.s.sertion? The prince smiled, nodded, and the menu was approved.25 A bit further on, Brillat-Savarin considers the osmazome more explicitly: The greatest service rendered by chemistry to alimentary science is the discovery or even more, the exact comprehension of osmazome.Osmazome is that preeminently sapid part of meat which is soluble in cold water, and which differs completely from the extractive part of the meat, which is soluble only in water that is boiling.It is osmazome which gives all its value to good soups; it is osmazome which, as it browns, makes the savory reddish tinge in sauces and the crisp coating on roasted meat; finally it is from the osmazome that come the special tangy juices of venison and game.This property is found mainly in mature animals with red flesh, blackish flesh, or whatever is meant by well-hung meat, the kind that is never or almost never found in lambs, suckling pigs, pullets, or even in the white meat of the largest fowls. It is for this reason that lovers of poultry have always preferred the second joint: in them the instinct for flavor came long before science confirmed it.It is also the infallible goodness of osmazome which has caused the dismissal of so many cooks, destined as they were to ruin their basic soup stock; it is osmazome which has made the reputation of the richest consommes, which once made toast soaked in bouillon a favorite restorative during weakening curative baths, and which inspired Canon Chevrier to invent a soup pot which locked with a key. (It is this same holy Father who never used to serve spinach on a Friday unless it had been cooking since the Sunday before, and put back each day on the stove with a new lump of fresh b.u.t.ter.)Finally, it is to husband this substance, as yet largely unrecognized, that the maxim has been propounded that in order to make a good bouillon the pot must only smile smile with heat, a truly worthy expression considering the country from which it came. with heat, a truly worthy expression considering the country from which it came.Osmazome, discovered at least after having for so long delighted our forebears, can be compared with alcohol, which tipsified many generations of men before any of them knew how to strip it naked in the a.n.a.lytical process of distillation in a laboratory. During the action of boiling water osmazome gives place to what is understood more especially by extractive matter: this last product, reunited with the osmazome, makes up the juice of meat. During the action of boiling water osmazome gives place to what is understood more especially by extractive matter: this last product, reunited with the osmazome, makes up the juice of meat.26 A Universal Flavor?
Even if it is scholarly and learned, this long treatise by our master gastronome is very wrong. Brillat-Savarin's osmazome is only a myth created in the era when a.n.a.lytical chemistry was in its infancy. It was the French chemist Louis Jacques Thenard who coined the term ”osmazome,” based on the Greek osme osme, ”odor,” and zomos zomos, ”soup.” He proposed it for the first time in an article in the Bulletin de la Faculte de medecine de Paris Bulletin de la Faculte de medecine de Paris in 1806. in 1806.
In his use of the term, Brillat-Savarin seems to suggest that the osmazome is a unique, well-defined compound, like the ethyl alcohol in alcoholic drinks. But modern methods of a.n.a.lysis show that the part of meat extracted cold is already a complex mix of water, lipids, various odorant molecules, salts, and more. In total, meat contains hundreds of sapid or odorant compounds. As for the first extract being the most sapid, let us trust our ancestors on this. They were more accustomed to boiling meat than we are, and, what is more, volatile molecules are often better perceived than the molecules the food retains, which activate neither the taste buds nor the nasal receptors.
On the other hand, Valery's aphorism according to which ”what is simple is always false” applies here to the osmazome. It is not the sapid element in meat; it is only one of the various flavorsome extracts that can be drawn from it.
And, if we are to believe Brillat-Savarin, it is the best.
How Does One Obtain a Flavorful Bouillon?
Let us think this through: meat contains many proteins. That is well known, and we eat meat for the protein it provides us. But what else does it contain? Amino acids, as these are produced when proteins are cooked for a very long time. These compounds are important because, as we have seen, they provide taste. What else? Fat! Just as important, but less well known, is the fact that meat fats are the main storage sites for odorant molecules. Beef tastes like beef because its fat contains the odorant molecules characteristic of beef. Mutton tastes like mutton because its fat contains the odorant molecules characteristic of mutton. And if little birds-larks, robins, buntings-each have their own delicate flavor, that is also because their fat contains the molecules characteristic of this small game.27 How to obtain a flavorful bouillon when the odorant compounds are in the fats, which are eliminated after cooking, once they have congealed?
First of all, let us note that compounds insoluble in water are never completely insoluble. In the presence of oil and water, they divide in specific proportions in each of the two substances. To extract a compound from oil that is not very soluble in water, one must simply agitate the oil in the presence of a large quant.i.ty of water. Then, when the extraction has been achieved, one can eliminate the oil and concentrate the water ... and the flavors.
In practice, we can trust Brillat-Savarin when it comes to obtaining a good bouillon, even if his instructions only give the appearance of being scientific: The water first of all dissolves part of the osmazome; then the alb.u.men, which coagulates at about 104 degrees Fahrenheit, forms a sc.u.m which is usually skimmed off; then the rest of the osmazome dissolves with the juice or extractive part; and so finally do portions of the outer coating of the fibers, which are pulled off by continuous movement of the boiling liquid.To make a good bouillon, the water must heat gradually, so that the alb.u.men will not coagulate inside the meat before it can be extracted; and the boiling must be kept at a simmer, so that the various parts which are successively dissolved may mix together easily.28 Does modern science confirm these precepts? It teaches us that the muscle fibers (the cells that make up the muscles) are composed of two proteins essential for contraction, actin and myosin, which are coated in collagen fibers.
It is the collagen that rigidifies meat and makes it tough. And it is to tenderize the collagen that meat is cooked for a long time in water. Over a long period of cooking, the collagen gradually pa.s.ses into the bouillon at the same time as it is partially decomposed. That is how gelatin is extracted from meat (or from bones, skin, and tendons, where gelatin is abundant).29 So why does the boiled beef in a stew retain its fibrous texture? Because, even if the collagen is solubilized, the proteins within the muscle fibers coagulate and are not solubilized.
Why should bouillon be covered when cooking? Because, as the bouillon boils, odorant molecules escape with the steam. As chefs will tell you, however, covering bouillon turns it cloudy. Why does it turn cloudy? That I do not know. How do you clarify a bouillon if it should become cloudy? By beating in an egg white, which coagulates around the particles that cloud your bouillon. You can also use good filtering tools from a chemistry laboratory, which are more effective and do not waste egg whites.