On Food And Cooking Part 71

Cream Cream

Mornay (a family) (a family)

Cheese, fish or poultry stock Cheese, fish or poultry stock

Soubise (army commander) (army commander)

Onion puree Onion puree

Basic Sauce: Hollandaise ("from Holland"), made with b.u.t.ter, eggs, lemon juice, or vinegar

Mousseline (light cloth) (light cloth)

Whipped cream Whipped cream

Bearnaise ("from Bearn") ("from Bearn")

White wine, vinegar, shallots, tarragon White wine, vinegar, shallots, tarragon

Basic Sauce: Mayonnaise (uncertain etymology), made with vegetable oil, eggs, vinegar, or lemon juice

Remoulade (twice ground) (twice ground)

Gherkins, capers, mustard, anchovy paste Gherkins, capers, mustard, anchovy paste

Sauces in England: Gravies and Condiments According to an 18th-century bon mot attributed to Domenico Caracciolli, with implicit contrast to France: "England has sixty religions and one sauce" - that one sauce being melted b.u.t.ter! And the sharp-toothed Alberto Denti di Pirajno begins the chapter on sauces in his According to an 18th-century bon mot attributed to Domenico Caracciolli, with implicit contrast to France: "England has sixty religions and one sauce" - that one sauce being melted b.u.t.ter! And the sharp-toothed Alberto Denti di Pirajno begins the chapter on sauces in his Educated Gastronome Educated Gastronome (Venice, 1950) with these pointed sentences: (Venice, 1950) with these pointed sentences: Doctor Johnson defined a sauce as something which is eaten with food in order to improve its flavor. It would be difficult to believe that a man of the intelligence and culture of Dr. Johnson...had expressed himself in these terms, if we did not know that Dr. Johnson was English. Even today his compatriots, incapable of giving any flavor to their food, call on sauces to furnish their dishes that which their dishes do not have. This explains the sauces, the jellies and prepared extracts, the bottled sauces, the chutneys, chutneys, the the ketchups ketchups which populate the tables of this unfortunate people. which populate the tables of this unfortunate people.

England's culinary standards were not formed at the Court or in the n.o.ble houses; they remained grounded in the domestic habits and economies of the countryside. English cooks ridiculed French cooks for their essences and quintessences. The French gastronome Brillat-Savarin (17551826) tells the story of the prince of Soubise being presented with a request from his chef for 50 hams, to be used at one supper party. Accused of thievery, the chef responds that all this meat is essential for the sauces to be made: "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!" The prince is astonished, and won over, by this a.s.sertion of the cook's power to concentrate flavor. By contrast, in her popular 18th-century cookbook, the English writer Hannah Gla.s.se gives several French sauce recipes that require more meat than the meal they will accompany, and then remarks on "the Folly of these fine French Cooks" in running up such huge expenses for so little. Gla.s.se's princ.i.p.al sauce is "gravy," made by browning some meat, carrots, onions, several herbs and spices, shaking in some flour, adding water, and stewing. In the 19th century, similarly homely anchovy, oyster, parsley, egg, caper, and b.u.t.ter sauces were popular.

And the Worcestershire sauces and chutneys and ketchups that Denti di Pirajno mocked? These condiments had become a part of English cooking in the 17th century thanks to the commercial activities of the East India Company, which brought back Asian soy and fish sauces - including Indonesian kecap kecap (p. 499) - and pickled fruits and vegetables, all preserved foods with intensified flavors. Many of these preparations are rich in savory amino acids, and the English imitations were often made with similarly savory mushrooms and anchovies. Our familiar tomato ketchup is a sweetened version of salty, vinegary, spicy tomato preserves. So an English contemporary of Careme's, William Kitchiner, includes a recipe for bechamel in his recipe book, but also presents "Wow Wow Sauce," which contains parsley, pickled cuc.u.mbers or walnuts, b.u.t.ter, flour, broth, vinegar, catsup, and mustard. These strongly flavored concoctions were quick and easy to use, and were evidently enjoyed for their strong contrast to the flavor of the foods they accompanied, not for subtle enhancement. (p. 499) - and pickled fruits and vegetables, all preserved foods with intensified flavors. Many of these preparations are rich in savory amino acids, and the English imitations were often made with similarly savory mushrooms and anchovies. Our familiar tomato ketchup is a sweetened version of salty, vinegary, spicy tomato preserves. So an English contemporary of Careme's, William Kitchiner, includes a recipe for bechamel in his recipe book, but also presents "Wow Wow Sauce," which contains parsley, pickled cuc.u.mbers or walnuts, b.u.t.ter, flour, broth, vinegar, catsup, and mustard. These strongly flavored concoctions were quick and easy to use, and were evidently enjoyed for their strong contrast to the flavor of the foods they accompanied, not for subtle enhancement.

Modern Sauces: Nouvelle and Post-Nouvelle The 20th Century: Nouvelle Cuisine Back in the 18th century, Francois Marin and his colleagues described their bouillon-based cooking as Back in the 18th century, Francois Marin and his colleagues described their bouillon-based cooking as nouvelle cuisine, nouvelle cuisine, or the "new cooking." In the hands of Careme and Escoffier, that or the "new cooking." In the hands of Careme and Escoffier, that nouvelle cuisine nouvelle cuisine was augmented with a few new sauces and became cla.s.sic French cooking, the standard throughout the western world for fine dining. In time, the cla.s.sic system became increasingly rigid and predictable, with most chefs essentially preparing the same standard dishes from the same precooked sauce bases. The 20th century brought a new was augmented with a few new sauces and became cla.s.sic French cooking, the standard throughout the western world for fine dining. In time, the cla.s.sic system became increasingly rigid and predictable, with most chefs essentially preparing the same standard dishes from the same precooked sauce bases. The 20th century brought a new nouvelle cuisine, nouvelle cuisine, along with the New Novel and the New Wave in cinema. In the 1960s a number of well established French chefs, including Paul Bocuse, Michel Guerard, the Troisgros family, and Alain Chapel, led the way in rethinking the French tradition. They a.s.serted the chef's creative role and the virtues of simplicity, economy, and freshness. Foods were no longer to be distilled into their essences, but were to be presented intact, as themselves. along with the New Novel and the New Wave in cinema. In the 1960s a number of well established French chefs, including Paul Bocuse, Michel Guerard, the Troisgros family, and Alain Chapel, led the way in rethinking the French tradition. They a.s.serted the chef's creative role and the virtues of simplicity, economy, and freshness. Foods were no longer to be distilled into their essences, but were to be presented intact, as themselves.

In 1976, the journalists Henri Gault and Christian Millau published the Ten Commandments of nouvelle cuisine, nouvelle cuisine, of which the seventh was: "You shall eliminate brown and white sauces." The new cooks still thought that, in the words of Michel Guerard, "the great sauces of France must be described as the cornerstones of cuisine," but they used them more selectively and with restraint. Lighter-flavored veal, chicken, and fish stocks served as poaching and braising liquids; reductions of these were used to give depth to last-minute pan sauces; and sauces in general were thickened less with flour and starch, more often with cream, b.u.t.ter, yogurt and fresh cheese, vegetable purees, and with bubbly foams. of which the seventh was: "You shall eliminate brown and white sauces." The new cooks still thought that, in the words of Michel Guerard, "the great sauces of France must be described as the cornerstones of cuisine," but they used them more selectively and with restraint. Lighter-flavored veal, chicken, and fish stocks served as poaching and braising liquids; reductions of these were used to give depth to last-minute pan sauces; and sauces in general were thickened less with flour and starch, more often with cream, b.u.t.ter, yogurt and fresh cheese, vegetable purees, and with bubbly foams.

Post-Nouvelle: Diverse and Innovative Sauces At the opening of the 21st century, the cla.s.sic brown and white sauces have become scarce, so much so that perhaps we're ready to appreciate their virtues again. Those restaurant and home cooks who do serve time-consuming meat stocks and reductions seldom make them from scratch; these products are well suited to manufacture on an industrial scale, and good versions are available in frozen form. The rich cream and b.u.t.ter sauces popularized by the At the opening of the 21st century, the cla.s.sic brown and white sauces have become scarce, so much so that perhaps we're ready to appreciate their virtues again. Those restaurant and home cooks who do serve time-consuming meat stocks and reductions seldom make them from scratch; these products are well suited to manufacture on an industrial scale, and good versions are available in frozen form. The rich cream and b.u.t.ter sauces popularized by the nouvelle cuisine nouvelle cuisine have become less common; simpler broths, reduced pan deglazings, and vinaigrettes more so. Thanks to the international scope of modern cooking, restaurant diners encounter a wider range of sauces than ever before. Many of them are contrasting purees made from fruits, vegetables, nuts, and spices, or else thinner soy-and fish-based Asian dipping sauces; these are attractive to restaurateurs because they require less time, labor, and often less skill than the cla.s.sic French sauces. Similarly, home cooks are now likely to buy time-saving and versatile bottled sauces and dressings. And a few inventive chefs are experimenting with unusual tools and materials - among them liquid nitrogen, high-powered pulverizers, thickeners derived from seaweeds and microbes - to make new forms of suspensions, emulsions, foams, and jellies. have become less common; simpler broths, reduced pan deglazings, and vinaigrettes more so. Thanks to the international scope of modern cooking, restaurant diners encounter a wider range of sauces than ever before. Many of them are contrasting purees made from fruits, vegetables, nuts, and spices, or else thinner soy-and fish-based Asian dipping sauces; these are attractive to restaurateurs because they require less time, labor, and often less skill than the cla.s.sic French sauces. Similarly, home cooks are now likely to buy time-saving and versatile bottled sauces and dressings. And a few inventive chefs are experimenting with unusual tools and materials - among them liquid nitrogen, high-powered pulverizers, thickeners derived from seaweeds and microbes - to make new forms of suspensions, emulsions, foams, and jellies.

The subtleness and delicacy described by I Yin and Francois Marin are not especially prominent among contemporary sauces. On the other hand, never before in history have we had so many distillations of desire from which to choose!

The Science of Sauces: Flavor and Consistency Flavor in Sauces: Taste and Smell The primary purpose of a sauce is to provide flavor in the form of a liquid with a pleasing consistency. It's much easier to generalize about consistency, how it is created, and how it can go wrong, than to generalize about flavor. There are many thousands of different flavor molecules; they can be combined in untold numbers of ways, and different people perceive them differently. Still, it's useful to keep a few basic facts about flavor in mind when constructing a sauce.

The Nature of Flavor Flavor is mainly a combination of two different sensations, taste and smell. Taste is perceived on the tongue, and comes in five different sensations: saltiness, sweetness, sourness, savoriness, bitterness. The molecules that we taste - salt, sugars, sour acids, savory amino acids, bitter alkaloids - are all easily soluble in water. (The astringent sensation caused by tea and red wine is a form of touch, and the "hot" pungency of mustard is a form of pain. They are not true tastes, but we also perceive them on the tongue and their causes are also water-soluble molecules.) Smell is perceived in the upper nasal region, and comes in thousands of different aromas that we usually describe by the foods they remind us of, fruity or flowery or spicy or herbaceous or meaty. The molecules that we smell are more soluble in fat than in water, and tend to escape from water into the air, where our smell detectors can sniff them. Flavor is mainly a combination of two different sensations, taste and smell. Taste is perceived on the tongue, and comes in five different sensations: saltiness, sweetness, sourness, savoriness, bitterness. The molecules that we taste - salt, sugars, sour acids, savory amino acids, bitter alkaloids - are all easily soluble in water. (The astringent sensation caused by tea and red wine is a form of touch, and the "hot" pungency of mustard is a form of pain. They are not true tastes, but we also perceive them on the tongue and their causes are also water-soluble molecules.) Smell is perceived in the upper nasal region, and comes in thousands of different aromas that we usually describe by the foods they remind us of, fruity or flowery or spicy or herbaceous or meaty. The molecules that we smell are more soluble in fat than in water, and tend to escape from water into the air, where our smell detectors can sniff them.

It can be useful to think of taste as the backbone of a flavor, and smell as its fleshing out. Taste alone is what we experience when we take some food in the mouth and pinch our nostrils shut; smell alone is what we experience when we sniff some food without putting it in the mouth. Neither is fully satisfying on its own. And recent research has shown that taste sensations affect our smell sensations. In a sweet food, the presence of sugar enhances our perception of aromas, and in savory foods, the presence of salt has the same effect.

The Spectrum of Sauce Flavors When considered as carriers of flavor, sauces form a broad spectrum. At one end are simple mixtures that provide a pleasing contrast to the food itself, or add a flavor that it lacks. Melted b.u.t.ter offers a subtle richness, vinaigrette salad dressings and mayonnaise a tart richness, salsas tartness and pungency. At the other end of the spectrum are complex flavor mixtures that fill the mouth and nose with sensations, and provide a rich background into which the flavor of the food itself blends. Among these are the meat-based sauces of the French tradition, whose complexity comes largely from the extraction and concentration of savory amino acids and other taste molecules, and from the generation of meaty aromas by way of the browning reactions between amino acids and sugars (p. 778). Chinese braising liquids based on soy sauce are similarly complex thanks to the cooking and fermentation of the soybeans (p. 496), while the spice blends of India and Thailand and the moles of Mexico typically combine a half dozen or more strongly aromatic and pungent ingredients. When considered as carriers of flavor, sauces form a broad spectrum. At one end are simple mixtures that provide a pleasing contrast to the food itself, or add a flavor that it lacks. Melted b.u.t.ter offers a subtle richness, vinaigrette salad dressings and mayonnaise a tart richness, salsas tartness and pungency. At the other end of the spectrum are complex flavor mixtures that fill the mouth and nose with sensations, and provide a rich background into which the flavor of the food itself blends. Among these are the meat-based sauces of the French tradition, whose complexity comes largely from the extraction and concentration of savory amino acids and other taste molecules, and from the generation of meaty aromas by way of the browning reactions between amino acids and sugars (p. 778). Chinese braising liquids based on soy sauce are similarly complex thanks to the cooking and fermentation of the soybeans (p. 496), while the spice blends of India and Thailand and the moles of Mexico typically combine a half dozen or more strongly aromatic and pungent ingredients.

Improving Sauce Flavor Perhaps the most common problem with sauce flavor is that there doesn't seem to be enough of it, or that "there's something missing" in it. Perfecting the flavor of any dish is an art that depends on the perceptiveness and skill of the cook, but there are two basic principles that can help anyone a.n.a.lyze and improve a sauce's flavor. Perhaps the most common problem with sauce flavor is that there doesn't seem to be enough of it, or that "there's something missing" in it. Perfecting the flavor of any dish is an art that depends on the perceptiveness and skill of the cook, but there are two basic principles that can help anyone a.n.a.lyze and improve a sauce's flavor.

Sauces are an accompaniment to a primary food, are eaten in small amounts compared to the primary food, and therefore need to have a concentrated flavor. A spoonful of sauce alone should taste too strong, so that a little sauce on a piece of meat or pasta will taste just right. Thickening agents tend to reduce the flavor of a sauce (p. 596), so it's important to check and adjust the flavor after thickening.

A satisfying sauce offers stimulation to most of our chemical senses. A sauce that doesn't seem quite right is probably deficient in one or more tastes, or doesn't carry enough aroma. The cook can taste the sauce actively for its saltiness, sweetness, acidity, savoriness, and aroma, and then try to correct the deficiencies while maintaining the overall balance of flavors.

Sauce Consistency Though the main point of sauces is their flavor, we also enjoy them for their consistency, their feeling in the mouth. And problems with consistency - with the sauce's physical structure - are far more likely than flavor problems to make a sauce unusable. Curdled or congealed or separated sauces are not pleasant to look at or to feel in the mouth. So it's good to understand the physical structures of common sauces, how they're put together and how they're ruined.

Food Dispersions: Mixtures That Create Texture The base ingredient in nearly all flavorful food liquids is water. That's because foods themselves are mostly water. Meat juices, vegetable and fruit purees are all obviously watery; cream and mayonnaise and the hot egg sauces less obviously so, but they too are built on water. In each of these preparations, water is the The base ingredient in nearly all flavorful food liquids is water. That's because foods themselves are mostly water. Meat juices, vegetable and fruit purees are all obviously watery; cream and mayonnaise and the hot egg sauces less obviously so, but they too are built on water. In each of these preparations, water is the continuous phase continuous phase: the material that bathes all the other components, the material in which all the other components swim. (The only common exceptions are some vinaigrettes and b.u.t.ter and nut b.u.t.ters, in which fat is the continuous phase.) Those other components are the dispersed phase. dispersed phase. The task of giving sauces a desirable consistency is a matter of making the continuous, base phase of water seem less watery, more substantial. The way this is done is to add some nonwatery substance - a dispersed phase - to the water. This substance may be particles of plant or animal tissue, or various molecules, or droplets of oil, or even bubbles of air. And how do the added substances make the water seem more substantial? By obstructing the free movement of the water molecules. The task of giving sauces a desirable consistency is a matter of making the continuous, base phase of water seem less watery, more substantial. The way this is done is to add some nonwatery substance - a dispersed phase - to the water. This substance may be particles of plant or animal tissue, or various molecules, or droplets of oil, or even bubbles of air. And how do the added substances make the water seem more substantial? By obstructing the free movement of the water molecules.

Obstructing the Movement of Water Molecules Individual water molecules are small - just three atoms, H Individual water molecules are small - just three atoms, H2O. Left to themselves, they're very mobile: so water is runny and flows as easily as a stream. (Oil molecules, by contrast, have three chains stuck together, each 14 to 20 atoms long, so they drag against each other and move more slowly. This is why oil is more viscous than water.) But intersperse solid particles or long, tangly molecules, or oil droplets, or air bubbles among the water molecules, and the water molecules can move only a small distance before they collide with one of these foreign, less mobile substances. They're then able to make only slow progress, so they flow more reluctantly.

Food Words: Liaison LiaisonTo name both the act of thickening and the agents of thickening, early French cooks used the word liaison, liaison, which meant a close connection or bond, whether physical, political, or amorous. When the English got around to borrowing the word in the 17th century, it was the culinary application that came first; military and romantic liaisons didn't arrive until the 19th century. which meant a close connection or bond, whether physical, political, or amorous. When the English got around to borrowing the word in the 17th century, it was the culinary application that came first; military and romantic liaisons didn't arrive until the 19th century.

Thickening agents in saucemaking are just such obstructing agents. Cooks have traditionally thought of them as binding agents, and this view makes its own kind of sense. The dispersed materials essentially divide the liquid into many small, local ma.s.ses: and by dividing, they organize and collect it and give it a kind of coherence that it lacked beforehand. Some thickening agents also literally bind water molecules to themselves and so take them out of circulation altogether, and this too has the effect of reducing the fluidity of the continuous phase.

In addition to giving watery fluids a thicker consistency, the substances in the dispersed phase can give them textures of various kinds. Solid particles may make them grainy or smooth, depending on the particle size; oil droplets make them seem creamy; dispersed molecules with a tendency to adhere to each other may make them seem sticky or slimy; air bubbles make them seem light and evanescent.

There are four common ways of thickening watery food juices. Each produces a different kind of physical system, and lends different qualities to the finished sauce.

Cloudy Suspensions: Thickening with Particles Most of our raw ingredients - vegetables, fruits, herbs, meats - are plant or animal tissues built from microscopic cells that are filled with watery fluids. The cells are contained within walls, membranes, or thin sheets of connective tissue. (Dry seeds and spices contain no juices, but are still made up of solid cells and cell walls.) When any of these foods is broken apart into small pieces by being ground in a mortar or pulverized in a blender, they are turned inside out, so the fluids form a continuous phase that contains fragments of the solid cell walls and connective tissue. These fragments obstruct and bind the water molecules, and thus thicken the consistency of the mixture. Such a mixture of a fluid and solid particles is called a Most of our raw ingredients - vegetables, fruits, herbs, meats - are plant or animal tissues built from microscopic cells that are filled with watery fluids. The cells are contained within walls, membranes, or thin sheets of connective tissue. (Dry seeds and spices contain no juices, but are still made up of solid cells and cell walls.) When any of these foods is broken apart into small pieces by being ground in a mortar or pulverized in a blender, they are turned inside out, so the fluids form a continuous phase that contains fragments of the solid cell walls and connective tissue. These fragments obstruct and bind the water molecules, and thus thicken the consistency of the mixture. Such a mixture of a fluid and solid particles is called a suspension suspension: the particles are suspended in the fluid. Sauces made from pureed foods are suspensions.

The texture of a suspension depends on the size of its particles. The smaller the particles, the less noticeable they are to the tongue, and the smoother the texture. Also, the smaller the particles are, the more of them there are to do the obstructing and the more surface area they have to take up a layer of water molecules: and so the thicker the consistency they produce. Suspensions are always opaque, because the solid particles are large enough to block the pa.s.sage of light rays and either absorb them or bounce them back toward their source. Because the particles and water are very different materials, suspensions tend to settle and separate into thin fluid and concentrated particles. Cooks work to prevent separation by reducing the volume of the continuous phase (draining off or boiling away excess water), or by augmenting the dispersed phase (adding starch or other long molecules or fat droplets).

Nut b.u.t.ters and chocolate are suspensions of solid seed particles not in water, but in oils and fats.

Thickening a liquid with food particles. In a suspension, microscopic chunks of plant or animal tissue are suspended in liquid, and give the impression of thickness by interfering with the liquid's flow.

Clear Dispersions and Gels: Thickening with Molecules A single microscopic fragment of a tomato cell wall or muscle fiber is built up of many thousands of submicroscopic molecules. Not all of the large molecules in those fragments can be teased away from each other so that they are individually dispersed in water. But those that can be extracted in this way - starch, pectins, such proteins as gelatin - are very useful thickening agents. Because single molecules are so much smaller and lighter than intact starch granules and cell fragments, they don't settle out and separate. And they are too small and too widely separated to block the pa.s.sage of light rays: so unlike suspensions, molecular dispersions are usually translucent and gla.s.sy-looking. In general, the longer the molecule, the better it is at obstructing water movement, because long molecules more readily get tangled up in each other. So a small quant.i.ty of long amylose starch molecules will do the same thickening job as a large quant.i.ty of short amylopectin (p. 611), and long gelatin molecules thicken more efficiently than short ones. Thickening with molecules often requires heat, either to liberate the molecules from the larger structures - starch molecules from their granules, gelatin molecules from meat connective tissue - or to shake out compactly folded molecules - egg proteins - into their long, extended, tangly form. A single microscopic fragment of a tomato cell wall or muscle fiber is built up of many thousands of submicroscopic molecules. Not all of the large molecules in those fragments can be teased away from each other so that they are individually dispersed in water. But those that can be extracted in this way - starch, pectins, such proteins as gelatin - are very useful thickening agents. Because single molecules are so much smaller and lighter than intact starch granules and cell fragments, they don't settle out and separate. And they are too small and too widely separated to block the pa.s.sage of light rays: so unlike suspensions, molecular dispersions are usually translucent and gla.s.sy-looking. In general, the longer the molecule, the better it is at obstructing water movement, because long molecules more readily get tangled up in each other. So a small quant.i.ty of long amylose starch molecules will do the same thickening job as a large quant.i.ty of short amylopectin (p. 611), and long gelatin molecules thicken more efficiently than short ones. Thickening with molecules often requires heat, either to liberate the molecules from the larger structures - starch molecules from their granules, gelatin molecules from meat connective tissue - or to shake out compactly folded molecules - egg proteins - into their long, extended, tangly form.

Solid Dispersions: Jellies When the water phase of a food fluid has enough thickening molecules dissolved in it, and the fluid is left undisturbed and allowed to cool, those molecules can bond to each other and form a loose but continuous tangle or network that permeates the fluid, with the water immobilized in pockets between the network molecules. Such a network thickens the fluid to the point that it becomes a very moist solid, or a When the water phase of a food fluid has enough thickening molecules dissolved in it, and the fluid is left undisturbed and allowed to cool, those molecules can bond to each other and form a loose but continuous tangle or network that permeates the fluid, with the water immobilized in pockets between the network molecules. Such a network thickens the fluid to the point that it becomes a very moist solid, or a gel. gel. It's possible to make a solid - if wobbly - jelly that is 99% water and just 1% gelatin. If the gel is made from dissolved molecules, then it will be translucent, like the dispersion from which it is formed. Familiar examples are savory jellies made from gelatin and sweet jellies made from fruit pectin. If the solution also contains particles - the remains of starch granules, for example - then the jelly will be opaque. It's possible to make a solid - if wobbly - jelly that is 99% water and just 1% gelatin. If the gel is made from dissolved molecules, then it will be translucent, like the dispersion from which it is formed. Familiar examples are savory jellies made from gelatin and sweet jellies made from fruit pectin. If the solution also contains particles - the remains of starch granules, for example - then the jelly will be opaque.

Thickening a liquid with long food molecules. Dissolved molecules of plant starch or animal gelatin get tangled up with each other and impede the flow of the liquid.

Emulsions: Thickening with Droplets Thanks to their very different structures and properties, water molecules and oil molecules don't mix evenly with each other(p. 797). Neither can dissolve in the other. If we use a whisk or blender to force a small portion of oil to mix into a larger one of water, the two form a milky, thick fluid. Both the milkiness and the thickness are caused by small droplets of oil, which block light rays and the free movement of water molecules. The oil droplets thus behave much as the solid particles in a suspension do. Such a mixture of two incompatible liquids, with droplets of one liquid dispersed in a continuous phase of the other, is called an Thanks to their very different structures and properties, water molecules and oil molecules don't mix evenly with each other(p. 797). Neither can dissolve in the other. If we use a whisk or blender to force a small portion of oil to mix into a larger one of water, the two form a milky, thick fluid. Both the milkiness and the thickness are caused by small droplets of oil, which block light rays and the free movement of water molecules. The oil droplets thus behave much as the solid particles in a suspension do. Such a mixture of two incompatible liquids, with droplets of one liquid dispersed in a continuous phase of the other, is called an emulsion. emulsion. The term comes from the Latin word for "milk," which is just such a mixture (p. 17). The term comes from the Latin word for "milk," which is just such a mixture (p. 17).

Emulsifiers In addition to the two incompatible liquids, a successful emulsion requires a third ingredient: an In addition to the two incompatible liquids, a successful emulsion requires a third ingredient: an emulsifier. emulsifier. An emulsifier is a substance of some kind that coats the oil droplets and prevents them from coalescing with each other. Several different materials can serve this function, including proteins, cell-wall fragments, and a group of hybrid molecules (for example, egg-yolk lecithin) that have an oil-like end and a water-soluble end (p. 802). To make an emulsified sauce, we add oil to a mixture of water and emulsifiers (egg yolk, ground herbs or spices), and break the oil up into microscopic droplets, which the emulsifiers immediately coat and stabilize. Or we can begin with a premade emulsion. Cream is an especially robust and versatile base for emulsified sauces. An emulsifier is a substance of some kind that coats the oil droplets and prevents them from coalescing with each other. Several different materials can serve this function, including proteins, cell-wall fragments, and a group of hybrid molecules (for example, egg-yolk lecithin) that have an oil-like end and a water-soluble end (p. 802). To make an emulsified sauce, we add oil to a mixture of water and emulsifiers (egg yolk, ground herbs or spices), and break the oil up into microscopic droplets, which the emulsifiers immediately coat and stabilize. Or we can begin with a premade emulsion. Cream is an especially robust and versatile base for emulsified sauces.

Foams: Thickening with Bubbles At first it seems surprising that a fluid can be thickened by adding air to it. Air is the opposite of substantial! Yet think of the foams on an espresso coffee or a gla.s.s of beer: they all have enough body to hold their shape when scooped with a spoon. Similarly, a pancake batter gets noticeably thicker if you stir the chemical leavening in last. In a fluid, air bubbles have much the same effect as solid particles: they interrupt the ma.s.s of water molecules and obstruct the water's flow from one place to another. The disadvantage of foams is that they are fragile and evanescent. The force of gravity unceasingly drains fluid from the bubble walls, and when the walls get just a few molecules thick, they break, the bubbles pop, and the foam collapses. This outcome can be delayed in a couple of ways. The cook can thicken the fluid with truly substantial particles or molecules (oil droplets, egg proteins) to slow its drainage from the bubble cell walls, or include emulsifiers (egg-yolk lecithin) that stabilize the bubble structure itself. On the other hand, the very delicacy and evanescence of unreinforced foams is a part of their appeal. Such foams must be prepared at the last minute and savored as they disappear. At first it seems surprising that a fluid can be thickened by adding air to it. Air is the opposite of substantial! Yet think of the foams on an espresso coffee or a gla.s.s of beer: they all have enough body to hold their shape when scooped with a spoon. Similarly, a pancake batter gets noticeably thicker if you stir the chemical leavening in last. In a fluid, air bubbles have much the same effect as solid particles: they interrupt the ma.s.s of water molecules and obstruct the water's flow from one place to another. The disadvantage of foams is that they are fragile and evanescent. The force of gravity unceasingly drains fluid from the bubble walls, and when the walls get just a few molecules thick, they break, the bubbles pop, and the foam collapses. This outcome can be delayed in a couple of ways. The cook can thicken the fluid with truly substantial particles or molecules (oil droplets, egg proteins) to slow its drainage from the bubble cell walls, or include emulsifiers (egg-yolk lecithin) that stabilize the bubble structure itself. On the other hand, the very delicacy and evanescence of unreinforced foams is a part of their appeal. Such foams must be prepared at the last minute and savored as they disappear.

Thickening a liquid with oil droplets and air bubbles. These tiny spheres act much as solid food particles do, interfering with the flow of the liquid surrounding them.

Real Sauces: Multiple Thickeners The sauces that cooks actually make are seldom simple suspensions, molecular dispersions, emulsions, or foams. They're usually a combination of two or more. Purees usually contain both suspended particles and dispersed molecules, starch-thickened sauces contain both dispersed molecules and remnants of the granules, emulsified sauces include proteins and particles from milk or eggs or spices. Cooks often thicken and enrich sauces of all kinds at the last minute by melting a piece of b.u.t.ter into it or stirring in a spoonful of cream, thus making them in part a milkfat emulsion. Such complexity of the dispersed phase may well make sauce texture more subtle and intriguing. The sauces that cooks actually make are seldom simple suspensions, molecular dispersions, emulsions, or foams. They're usually a combination of two or more. Purees usually contain both suspended particles and dispersed molecules, starch-thickened sauces contain both dispersed molecules and remnants of the granules, emulsified sauces include proteins and particles from milk or eggs or spices. Cooks often thicken and enrich sauces of all kinds at the last minute by melting a piece of b.u.t.ter into it or stirring in a spoonful of cream, thus making them in part a milkfat emulsion. Such complexity of the dispersed phase may well make sauce texture more subtle and intriguing.

The Influence of Consistency on Flavor Thickeners Reduce Flavor Intensity In general, the components of a sauce that create its consistency have little or no flavor of their own. They therefore only dilute whatever flavors the sauce has. Thickening agents also actively reduce the effectiveness of the flavor molecules in the sauce. They bind some of those molecules so that our palate never senses them, and they slow their movement from the sauce into our taste buds or nasal pa.s.sages. Because aroma molecules tend to be more fat soluble than water soluble, fat in a sauce hangs onto aroma molecules and decreases aromatic intensity. Amylose starch molecules trap aroma molecules (the aroma molecules in turn make the starch molecules more likely to bond to each other into light-scattering, milky aggregates). And wheat flour binds more sodium than pure starches, so flour-thickened preparations require more added salt than starch-thickened sauces. In general, the components of a sauce that create its consistency have little or no flavor of their own. They therefore only dilute whatever flavors the sauce has. Thickening agents also actively reduce the effectiveness of the flavor molecules in the sauce. They bind some of those molecules so that our palate never senses them, and they slow their movement from the sauce into our taste buds or nasal pa.s.sages. Because aroma molecules tend to be more fat soluble than water soluble, fat in a sauce hangs onto aroma molecules and decreases aromatic intensity. Amylose starch molecules trap aroma molecules (the aroma molecules in turn make the starch molecules more likely to bond to each other into light-scattering, milky aggregates). And wheat flour binds more sodium than pure starches, so flour-thickened preparations require more added salt than starch-thickened sauces.

As a general rule, then, a thin sauce will have a more intense and immediate flavor than the same sauce with thickeners added. But the thickened sauce will release its flavor more gradually and persistently. Each effect has its uses.

Many sauces can be thickened not just by adding thickeners, but by removing some of the continuous phase - boiling off water - so that the thickeners already present in the sauce become more concentrated. This technique doesn't diminish flavor, because whatever flavor the sauce's particles and molecules can bind have already been bound. And in fact it can intensify flavor, because the concentration of flavor molecules may increase just as the thickeners' concentration does.

The Importance of Salt Recent research has uncovered intriguing indications that thickeners reduce our perception of aroma in part because they reduce our perception of saltiness. Various long-chain carbohydrates, including starch, first reduce the apparent saltiness of the sauce, either by binding sodium ions to themselves or by adding another sensation (viscosity) for the brain to attend to. Then this reduced saltiness reduces the apparent aroma intensity - despite the fact that the same number of aroma molecules are flowing out of the sauce and across the smell receptors in our nose. The practical significance of this finding is that thickening a sauce with flour or starch diminishes its overall flavor, and that both taste Recent research has uncovered intriguing indications that thickeners reduce our perception of aroma in part because they reduce our perception of saltiness. Various long-chain carbohydrates, including starch, first reduce the apparent saltiness of the sauce, either by binding sodium ions to themselves or by adding another sensation (viscosity) for the brain to attend to. Then this reduced saltiness reduces the apparent aroma intensity - despite the fact that the same number of aroma molecules are flowing out of the sauce and across the smell receptors in our nose. The practical significance of this finding is that thickening a sauce with flour or starch diminishes its overall flavor, and that both taste and and aroma can be restored to some extent by the simple addition of more salt. aroma can be restored to some extent by the simple addition of more salt.

Sauces Thickened with Gelatin and Other Proteins If we gently heat a piece of meat or fish alone in a pan, it releases flavorful juices. Normally we make the pan hot enough to evaporate the water the moment it comes out, so that the flavor molecules become concentrated on the meat and pan surfaces, and react with each other to form brown pigments and a host of new flavor molecules (p. 778). But if the juices remain juices, they const.i.tute a very basic sauce, a product of the meat that can be added back to moisten and flavor the ma.s.s of coagulated muscle protein from which they've been squeezed. The problem is that the meat or fish only gives up a small amount of juice compared to the solid ma.s.s. To satisfy fully our appet.i.te for those juices, cooks have invented methods for making meat and fish sauces for their own sake, and in any quant.i.ty. The main thickening agent in these sauces is gelatin, an unusual protein that cooking releases from the meat and fish. Cooks also use other animal proteins to thicken sauces, but their behavior is very different and more problematic, as we'll see (p. 603).

The Uniqueness of Gelatin Gelatin is a protein, but it's unlike the other proteins that the cook works with. Nearly all food proteins respond to the heat of cooking by unfolding, bonding permanently to each other, and coagulating into a firm, solid ma.s.s. It turns out that gelatin molecules can't easily form permanent bonds with each other, due to their particular chemical makeup. So heat simply causes them to shake loose from the weak, temporary bonds that hold them together, and disperses them in water. Because gelatin molecules are very long and get tangled up with each other, they give the mixture a definite body, and can even set it into a solid gel (p. 605). However, gelatin is relatively inefficient at thickening. Its molecules are very flexible, while those of starch and other carbohydrates are rigid and better at interfering with the movement of water and each other. This is one reason why gelatin-thickened sauces are usually augmented with starch. A sauce that contains only gelatin requires a large concentration, 10% or more, to have real weight. But at that concentration, the sauce is quick to congeal on a cooling plate, and it can also cause the teeth to stick together (gelatin makes an excellent glue!).

Gelatin Comes from Collagen Free gelatin molecules don't exist in meat and fish. They're woven tightly together to form the fibrous connective-tissue protein called collagen (p. 130), which gives mechanical strength to muscles, tendons, skin, and bones. Single gelatin molecules are chains of around 1,000 amino acids. Thanks to the repeating pattern of their amino acids, three gelatin molecules naturally fit alongside each other and form weak, reversible bonds that arrange the three molecules in the form of a triple helix. Many triple helixes then become cross-linked to each other to form the strong, rope-like fibers of collagen. Free gelatin molecules don't exist in meat and fish. They're woven tightly together to form the fibrous connective-tissue protein called collagen (p. 130), which gives mechanical strength to muscles, tendons, skin, and bones. Single gelatin molecules are chains of around 1,000 amino acids. Thanks to the repeating pattern of their amino acids, three gelatin molecules naturally fit alongside each other and form weak, reversible bonds that arrange the three molecules in the form of a triple helix. Many triple helixes then become cross-linked to each other to form the strong, rope-like fibers of collagen.

Cooks generate gelatin from collagen by using heat to dismantle the collagen fibers. For the muscles of land animals, it takes a temperature of around 140F/60C to agitate the muscle molecules enough to break the weak bonds of the triple helix. The orderly structure of the collagen fibers then collapses and the fibers shrink, thus squeezing juices from the muscle fibers. Some of the juices bathe the fibers, and single gelatin molecules or small aggregates may disperse into the juice. The higher the meat temperature goes, the more gelatin becomes dispersed. However, many of the collagen fibers remain intact thanks to the strong cross-linking bonds. The older the animal and the more work its muscles do, the more strongly cross-linked its collagen fibers are.

Extracting Gelatin and Flavor from Meats The muscles that make up meat are mainly water and the protein fibers that do the work of contraction, which are not dispersable in water. The soluble and dispersable materials in muscle include about 1% by weight of collagen, 5% other cell proteins, 2% amino acids and other savory molecules, 1% sugars and other carbohydrates, and 1% minerals, mainly phosphorus and pota.s.sium. Bones are around 20% collagen, pig skin around 30%, and cartilaginous veal knuckles up to 40%. Bones and skin are thus much better sources of gelatin and thickening power than meat. However, they carry only a small fraction of the other soluble molecules that provide flavor. To make sauces with good meat flavor, it's meat that must be extracted, not bones or skin.

When meat is thoroughly cooked, it releases about 40% of its weight in juice, and the flow of juice pretty much ends when the tissue reaches 160F/70C. Most of the juice is water, and the rest the soluble molecules carried in the water. If meat is cooked in water, then gelatin can be freed from the connective tissue and extracted over a long period of time. When cooks make stocks, extraction times range from less than an hour for fish, to a few hours for chicken or veal stocks, to a day for beef. Optimum extraction times depend on the size of the bones and meat pieces, and on the age of the animal; the more cross-linked collagen of a steer takes longer to free than the collagen from a veal calf. At long extraction times, the gelatin molecules that have already been dissolved are gradually broken down into smaller pieces that are less efficient thickeners.

Meat Stocks and Sauces There are several general strategies for making meat and fish sauces. The simplest of them center on the juices produced when the meat for the final dish is cooked, which can be flavored and/or thickened at the last minute with purees, emulsions, or a starch-based mixture. In the more versatile system developed by French cooks, one begins by making a water extract of meat and bones ahead of time, and then uses that stock to cook the final dish, or concentrates it to make intensely flavored, full-bodied sauces. These stocks and concentrates used to be the heart of restaurant cooking. They're less important now, but still represent the state of the art in meat sauces.

Collagen and gelatin. Collagen molecules (left) (left) contribute mechanical strength to connective tissue and bone in animal muscles. They are made up of three individual protein chains wound closely together into a helix to make a rope-like fiber. When heated in water, the individual protein chains come apart contribute mechanical strength to connective tissue and bone in animal muscles. They are made up of three individual protein chains wound closely together into a helix to make a rope-like fiber. When heated in water, the individual protein chains come apart (right) (right) and dissolve into the water. The unwound, separate chains are what we call gelatin. and dissolve into the water. The unwound, separate chains are what we call gelatin.

The Choice of Ingredients The aim in making meat stock is to produce a full-flavored liquid with enough gelatin that it will also become full-bodied when reduced. Meat is an expensive ingredient, an excellent source of flavor, and a modest source of gelatin. Bones and skins are less expensive, poor sources of flavor, but excellent sources of gelatin. So the most flavorful and expensive stocks are made with meat, the fullest bodied and cheapest with bones and pork skin, and everyday stocks with some of each. Beef and chicken stocks taste distinctly of their respective meats, while veal bones and meat are valued for their more neutral character, as well as their higher yield of soluble gelatin. Cartilaginous veal knuckles and feet give especially large amounts. Typically, the meat and bones are cooked in between one and two times their weight in water (12 quarts or liters per 2 lb/1 kg solids), and yield about half their weight in stock, thanks to gradual evaporation during cooking. The smaller the pieces into which they're cut, the more quickly their contents can be extracted in the water. The aim in making meat stock is to produce a full-flavored liquid with enough gelatin that it will also become full-bodied when reduced. Meat is an expensive ingredient, an excellent source of flavor, and a modest source of gelatin. Bones and skins are less expensive, poor sources of flavor, but excellent sources of gelatin. So the most flavorful and expensive stocks are made with meat, the fullest bodied and cheapest with bones and pork skin, and everyday stocks with some of each. Beef and chicken stocks taste distinctly of their respective meats, while veal bones and meat are valued for their more neutral character, as well as their higher yield of soluble gelatin. Cartilaginous veal knuckles and feet give especially large amounts. Typically, the meat and bones are cooked in between one and two times their weight in water (12 quarts or liters per 2 lb/1 kg solids), and yield about half their weight in stock, thanks to gradual evaporation during cooking. The smaller the pieces into which they're cut, the more quickly their contents can be extracted in the water.

In order to round out the flavor of a stock, cooks usually cook the meat and bones along with aromatic vegetables - celery, carrots, onions - a packet of herbs, and sometimes wine. Carrots and onions contribute sweetness as well as aroma, wine tartness and savoriness. Salt is never added at this stage, because the meats and vegetables release some, and it becomes concentrated as the stock reduces.

Cooking the Stock A cla.s.sic meat stock should be as clear as possible, so that it can be made into soup broths and aspics that will be attractive to the eye. Many of the details of stock making have to do with removing impurities, especially the soluble cell proteins that coagulate into unsightly gray particles. A cla.s.sic meat stock should be as clear as possible, so that it can be made into soup broths and aspics that will be attractive to the eye. Many of the details of stock making have to do with removing impurities, especially the soluble cell proteins that coagulate into unsightly gray particles.

The bones and often meat as well (and skin, if any) are first washed thoroughly. To make a light stock, they are then put in a pot of cold water that is brought to the boil; they're then removed from the pot and rinsed. This blanching step removes surface impurities and coagulates surface proteins on the bones and meat so that they won't cloud the cooking liquid. To make a dark stock for brown sauces, the bones and meat are first roasted in a hot oven to produce color and a more intense roasted-meat flavor with the Maillard reactions between proteins and carbohydrates. This process also coagulates the surface proteins and makes blanching unnecessary.

The Importance of a Cold Start and Uncovered, Slow Heating After the blanching or browning, the meat solids are started in an uncovered pot of cold water, which the cook brings slowly to a gentle simmer and keeps there, regularly skimming off the fat and sc.u.m that acc.u.mulate at the surface. The cold start and slow heating allow the soluble proteins to escape the solids and coagulate slowly, forming large aggregates that either rise to the surface and are easily skimmed off, or settle onto the sides and bottom. A hot start produces many separate and tiny protein particles that remain suspended and cloud the stock; and a boil churns particles and fat droplets into a cloudy suspension and emulsion. The pot is left uncovered for several reasons. Because this allows water to evaporate and cool the surface, it makes it less likely that the stock will boil. It also dehydrates the surface sc.u.m, which becomes more insoluble and easier to skim. And it starts the process of concentration that will give the stock a more intense flavor. After the blanching or browning, the meat solids are started in an uncovered pot of cold water, which the cook brings slowly to a gentle simmer and keeps there, regularly skimming off the fat and sc.u.m that acc.u.mulate at the surface. The cold start and slow heating allow the soluble proteins to escape the solids and coagulate slowly, forming large aggregates that either rise to the surface and are easily skimmed off, or settle onto the sides and bottom. A hot start produces many separate and tiny protein particles that remain suspended and cloud the stock; and a boil churns particles and fat droplets into a cloudy suspension and emulsion. The pot is left uncovered for several reasons. Because this allows water to evaporate and cool the surface, it makes it less likely that the stock will boil. It also dehydrates the surface sc.u.m, which becomes more insoluble and easier to skim. And it starts the process of concentration that will give the stock a more intense flavor.

Food Words: Stock, Broth Stock, BrothThe word stock stock as it's applied in the kitchen reflects the professional cook's approach to sauce making. It derives from an old Germanic root meaning "tree trunk," and has more than 60 related meanings revolving around the idea of basic materials, sources, and supplies. It's thus the culinary application of a very general term, and was first used in the 18th century. Much more specific and ancient is as it's applied in the kitchen reflects the professional cook's approach to sauce making. It derives from an old Germanic root meaning "tree trunk," and has more than 60 related meanings revolving around the idea of basic materials, sources, and supplies. It's thus the culinary application of a very general term, and was first used in the 18th century. Much more specific and ancient is broth, broth, which goes back to 1000 which goes back to 1000 CE CE and a Germanic root and a Germanic root bru bru meaning "to prepare by boiling" and the material so prepared, both it and the boiling liquid. meaning "to prepare by boiling" and the material so prepared, both it and the boiling liquid. Bouillon Bouillon and and brew brew are related terms. are related terms.

Single and Double Stocks After the sc.u.m has mostly stopped forming, the vegetables, herbs, and wine are added and the cooking is continued at a gentle simmer until most of the flavor and gelatin have been extracted from the solids. The liquid is strained through cheesecloth or a metal strainer without pressing on the solids, which would extract cloudy particles. It's then thoroughly chilled, and the solidified fat removed from the surface. (If the cook doesn't have the time to chill the stock, he can soak away much of the fat from the surface with cloth or paper towels or specially designed plastic blotters.) The stock is now ready to use as an ingredient, to make braised and stewed meats and meat soups, or as a savory cooking liquid for vegetables; or it may be reduced for use in a sauce. The cook may also use stock to extract a new batch of meat and bones and produce the especially flavorful, highly prized - and expensive - double stock. (Double stock can in turn be combined with more fresh meat and bones to make a triple stock.) After the sc.u.m has mostly stopped forming, the vegetables, herbs, and wine are added and the cooking is continued at a gentle simmer until most of the flavor and gelatin have been extracted from the solids. The liquid is strained through cheesecloth or a metal strainer without pressing on the solids, which would extract cloudy particles. It's then thoroughly chilled, and the solidified fat removed from the surface. (If the cook doesn't have the time to chill the stock, he can soak away much of the fat from the surface with cloth or paper towels or specially designed plastic blotters.) The stock is now ready to use as an ingredient, to make braised and stewed meats and meat soups, or as a savory cooking liquid for vegetables; or it may be reduced for use in a sauce. The cook may also use stock to extract a new batch of meat and bones and produce the especially flavorful, highly prized - and expensive - double stock. (Double stock can in turn be combined with more fresh meat and bones to make a triple stock.) Because a standard kitchen extraction of eight hours releases only about 20% of the gelatin in beef bones, the bones may be extracted for a second time, for a total of up to 24 hours. The resulting liquid can then be used to start the next fresh extraction of meat and bones.

Concentrating Meat Stocks: Glace Glace and and Demi-glace Demi-glace Slowly simmered until it's reduced to a tenth its original volume, stock becomes Slowly simmered until it's reduced to a tenth its original volume, stock becomes glace de viande, glace de viande, literally "meat ice" or "meat gla.s.s," which cools to a stiff, clear jelly. Glace has a thick, syrupy, sticky consistency thanks to its high gelatin content, about 25%, an intensely savory taste thanks to the concentrated amino acids, and a rounded, mellow, but somewhat flat aroma thanks to the long hours during which volatile molecules have been boiled off or reacted with each other. Meat glace is used in small quant.i.ties to lend flavor and body to sauces. Intermediate between stock and glace is literally "meat ice" or "meat gla.s.s," which cools to a stiff, clear jelly. Glace has a thick, syrupy, sticky consistency thanks to its high gelatin content, about 25%, an intensely savory taste thanks to the concentrated amino acids, and a rounded, mellow, but somewhat flat aroma thanks to the long hours during which volatile molecules have been boiled off or reacted with each other. Meat glace is used in small quant.i.ties to lend flavor and body to sauces. Intermediate between stock and glace is demi-glace demi-glace or "half- or "half-glace," which is stock simmered down to 2540% of its original volume, often with some tomato puree or paste to add flavor and color, and with some flour or starch to supplement its lower gelatin content (1015%). The tomato particles and flour gluten proteins cloud the stock and are removed by skimming the stock as it reduces, and then by a final straining. The starch in demi-glace, around 35% of its final weight, is largely an economy measure - it gives a greater thickness with less stock reduction and loss of volume to evaporation - but it also has the advantage of sparing some of the stock's flavor from being boiled off, and avoiding the sticky consistency of very concentrated gelatin.

Demi-glace is the base for many cla.s.sic French brown sauces, which are given particular flavors and nuances with the addition of various other ingredients (meats, vegetables, herbs, wine) and final enriching thickeners (b.u.t.ter, cream). Because they're versatile but tedious to prepare, demi-glace and glace are manufactured and widely available in frozen form.

Concentrating Stock and Flavor to Finish a DishAn alternative to cooking stock down in bulk is to reduce it in small quant.i.ties to augment the pan juices of a roast or saute. Once the meat is cooked and its juices concentrated and browned on the pan bottom, the cook can repeatedly add a small quant.i.ty of stock to the pan and cook it down until its solids begin to brown, then dissolve the successive brownings in a final dose of stock to make the liquid sauce. The high pan temperature helps break down the gelatin molecules into shorter lengths, so the resulting sauce is less sticky and congeals more slowly than it would if the gelatin were intact.

Consomme and Clarification with Egg Whites One of the most remarkable soups is consomme, an intensely flavored, amber-colored, clear liquid with a distinct but delicate body. (The name comes from the French for "to consume," "to use up," and referred to the medieval practice of cooking the meat broth down until it reached the right consistency.) It is made by preparing a basic stock mainly from meat, not flavor-poor bones or skin, and then clarifying it while simultaneously extracting a second batch of meat and vegetables. It's a kind of double stock made expressly for soup; as much as a pound/0.5 kg of meat may go into producing one serving. One of the most remarkable soups is consomme, an intensely flavored, amber-colored, clear liquid with a distinct but delicate body. (The name comes from the French for "to consume," "to use up," and referred to the medieval practice of cooking the meat broth down until it reached the right consistency.) It is made by preparing a basic stock mainly from meat, not flavor-poor bones or skin, and then clarifying it while simultaneously extracting a second batch of meat and vegetables. It's a kind of double stock made expressly for soup; as much as a pound/0.5 kg of meat may go into producing one serving.

The clarification of consomme is accomplished by stirring finely chopped meat and vegetables into the cold stock along with several lightly whisked egg whites. The mixture is then brought slowly to the simmer, and kept there for around an hour. As the stock heats up, the abundant egg white proteins begin to coagulate into a fine cheesecloth-like network, and essentially strain the liquid from within. Soluble proteins from the fresh batch of meat help produce large protein particles that are easily trapped by the egg-white network. Gradually the protein mesh rises to the top of the pot to form a "raft," which continues to collect particles brought to the surface by convection in the liquid. When the cooking is done, the raft is skimmed off and any remaining particles are removed by a final straining. The resulting liquid is very clear. Clarification with egg whites does remove both flavor molecules and some gelatin from the stock, which is why the cook supplies fresh meat and vegetables during the clarification.

Commercial Meat Extracts and Sauce Bases These days many restaurants and home cooks rely on commercial meat extracts and bases for making their sauces and soups. The pioneer of ma.s.s-produced meat extracts was Justus von Liebig, inventor of the mistaken theory that searing meat seals in the juices (p. 161), who was motivated by the equally mistaken belief that the soluble substances in meat contain most of its nutritional value. However, they do contain much of its savory flavor. Today, meat extracts are made by simmering meat sc.r.a.ps and/or bones in water, then clarifying the stock and evaporating off more than 90% of the water. The initial stock is more than 90% water and 34% dissolved meat components; the finished extract is a viscous material that is about 20% water, 50% amino acids, peptides, gelatin, and related molecules, 20% minerals, mainly phosphorus and pota.s.sium, and 5% salt. (There are also less concentrated flui