On Food And Cooking Part 87

Kind of Chocolate

Cooling Temperature Cooling Temperature

Dark

8284F/2829C 8284F/2829C

Milk

8082F/2728C 8082F/2728C

White

7476F/2425C 7476F/2425C

Kind of Chocolate

Tempering Range Tempering Range

Dark

8890F/3132C 8890F/3132C

Milk

8688F/3031C 8688F/3031C

White

8082F/2728C 8082F/2728C

Tempering Methods There are several different ways to obtain melted chocolate that is in temper. All of them require an accurate thermometer, a gentle heat source (often a pot of hot water over which the bowl of chocolate can be held), and the cook's full attention. And all of them end with the chocolate at a temperature where stable crystals can form and unstable crystals can't. There are several different ways to obtain melted chocolate that is in temper. All of them require an accurate thermometer, a gentle heat source (often a pot of hot water over which the bowl of chocolate can be held), and the cook's full attention. And all of them end with the chocolate at a temperature where stable crystals can form and unstable crystals can't.

Of the two common methods for tempering chocolate, one creates the stable crystals from scratch, while the other uses a small amount of tempered chocolate to "seed" the melted chocolate with stable crystals.

To temper the chocolate from scratch, heat it to 120F/50C to melt all crystals, and cool it down to around 105F/40C. Then either stir the chocolate as it cools further, until it thickens noticeably (an indication of crystal formation), or pour a portion onto a cool surface and sc.r.a.pe and mix it until it thickens, and return it to the bowl. Then carefully raise the temperature of the chocolate to the tempering range, 8890F/3132C, and stir to melt any unstable crystals that might have formed during the stirring or sc.r.a.ping.

To seed melted chocolate with stable crystals, chop and hold in reserve a portion of solid tempered chocolate. Heat the chocolate to be tempered to 120F/50C to melt all crystals, and cool it to 95100F/3538C, just above the temperature range in which stable crystals form. Then stir in the solid portion with its stable crystals, while keeping the temperature in the tempering range, 8890F/3132C.

No matter how chocolate is tempered, its temperature must be held in the tempering range until it is used. If allowed to cool, it will begin to solidify prematurely, won't flow evenly, and produces an uneven consistency and appearance.

Melting Tempered Chocolate While Maintaining It in Temper It's also possible to obtain tempered melted chocolate without actually doing the tempering. Nearly all manufactured chocolate is sold in tempered form. A cook using new, well-made chocolate can warm it carefully and directly to the tempering range, 8890F/3132C, so that it melts but still retains some of its desirable fat crystals. This is easily done by stirring the finely chopped chocolate in a bowl over a pot filled with water at 9095F/3234C. If for some reason the chocolate is overheated, so that it loses all of its fat crystals, or if the cook is using previously melted and resolidified chocolate with a mixture of crystals, then it's necessary to temper the chocolate with one of the methods described above. It's also possible to obtain tempered melted chocolate without actually doing the tempering. Nearly all manufactured chocolate is sold in tempered form. A cook using new, well-made chocolate can warm it carefully and directly to the tempering range, 8890F/3132C, so that it melts but still retains some of its desirable fat crystals. This is easily done by stirring the finely chopped chocolate in a bowl over a pot filled with water at 9095F/3234C. If for some reason the chocolate is overheated, so that it loses all of its fat crystals, or if the cook is using previously melted and resolidified chocolate with a mixture of crystals, then it's necessary to temper the chocolate with one of the methods described above.

Tempering chocolate. To make chocolate with stable fat crystals, the cook first heats the chocolate to melt all the crystals. In one method, he then cools the chocolate to the temperature range in which only stable crystals can form, adds a portion of tempered chocolate to provide stable crystal seeds, and keeps the mixture warm until it's used for molding or coating. In a second method (dotted line) (dotted line) , the cook allows the molten chocolate to cool below the stable-crystal temperature and form a mixture of crystal types, then warms it to melt the unstable crystals while retaining the stable ones. , the cook allows the molten chocolate to cool below the stable-crystal temperature and form a mixture of crystal types, then warms it to melt the unstable crystals while retaining the stable ones.

The Art of Tempering Though an accurate thermometer and careful temperature control are necessary for successful tempering, they aren't sufficient. The art of tempering lies in recognizing when the chocolate has acc.u.mulated Though an accurate thermometer and careful temperature control are necessary for successful tempering, they aren't sufficient. The art of tempering lies in recognizing when the chocolate has acc.u.mulated enough enough stable crystals to form a dense, hard network as it cools. Insufficient tempering time, or insufficient stirring, produce too few stable crystal seeds and undertempered chocolate, which will form some unstable crystals when it cools. Too much stirring or time produce too many or too large stable crystals and overtempered chocolate, in which individual crystals predominate over the joined network. Overtempered chocolate is stable, but it can seem coa.r.s.e, crumbly rather than snappy, dull in appearance, and waxy in the mouth. stable crystals to form a dense, hard network as it cools. Insufficient tempering time, or insufficient stirring, produce too few stable crystal seeds and undertempered chocolate, which will form some unstable crystals when it cools. Too much stirring or time produce too many or too large stable crystals and overtempered chocolate, in which individual crystals predominate over the joined network. Overtempered chocolate is stable, but it can seem coa.r.s.e, crumbly rather than snappy, dull in appearance, and waxy in the mouth.

Testing for Temper Molten chocolate can be tested for its temper by placing a small, thin portion on a room-temperature surface, a plate or piece of foil. Properly tempered chocolate solidifies in a few minutes to a clean, silky-surfaced ma.s.s; the side in contact with the cool surface is s.h.i.+ny. Chocolate out of temper takes many minutes to harden, and has an irregular powdery or grainy appearance. Molten chocolate can be tested for its temper by placing a small, thin portion on a room-temperature surface, a plate or piece of foil. Properly tempered chocolate solidifies in a few minutes to a clean, silky-surfaced ma.s.s; the side in contact with the cool surface is s.h.i.+ny. Chocolate out of temper takes many minutes to harden, and has an irregular powdery or grainy appearance.

Working with Tempered Chocolate Once chocolate has been tempered, it must be handled so that it stays in temper. It should be kept warm, in the tempering range of 8890F/3132C. When shaped, it should be poured into molds or coated onto fillings that are neither so cold that they cause the cocoa b.u.t.ter to solidify quickly and unstably, nor so warm that they melt the stable crystal seeds in the chocolate. Confectioners recommend a temperature around 77F/25C. Similarly, the room temperature should be moderate, neither chilly nor hot. Once chocolate has been tempered, it must be handled so that it stays in temper. It should be kept warm, in the tempering range of 8890F/3132C. When shaped, it should be poured into molds or coated onto fillings that are neither so cold that they cause the cocoa b.u.t.ter to solidify quickly and unstably, nor so warm that they melt the stable crystal seeds in the chocolate. Confectioners recommend a temperature around 77F/25C. Similarly, the room temperature should be moderate, neither chilly nor hot.

It turns out that tempered chocolate shrinks by about 2% in each dimension as it solidifies, because the fat molecules in the stable crystals are more densely packed than they were in liquid form. This shrinkage is helpful in making molded chocolates, because the chocolate pulls away from the mold as it hardens. But it can cause the thin coating on a candy or truffle to crack, especially if the filling is cold and expands slightly when coated with the warm chocolate. The snappy hardness of tempered chocolate takes several days to develop fully as the crystal network continues to grow and become stronger.

Specialty Coatings Ordinary chocolate is not well suited for certain kinds of coatings, including those on ice cream and other frozen ingredients, and candies that are eaten in the heat of the summer or the tropics. For these kinds of products, manufacturers have developed replacements for cocoa b.u.t.ter that don't require tempering to look good, break with a snap, and remain hard at high temperatures. Some closely resemble cocoa b.u.t.ter and can be mixed with chocolate, while others are very different, not compatible with chocolate, and must be flavored with low-fat cocoa. Among the former are fats purified from a number of tropical nuts (palm, shea, illipe, sal); among the latter are "lauric fats" derived from coconut and palm oils. Coatings made with these ingredients are often called "nontempering" chocolates. Ordinary chocolate is not well suited for certain kinds of coatings, including those on ice cream and other frozen ingredients, and candies that are eaten in the heat of the summer or the tropics. For these kinds of products, manufacturers have developed replacements for cocoa b.u.t.ter that don't require tempering to look good, break with a snap, and remain hard at high temperatures. Some closely resemble cocoa b.u.t.ter and can be mixed with chocolate, while others are very different, not compatible with chocolate, and must be flavored with low-fat cocoa. Among the former are fats purified from a number of tropical nuts (palm, shea, illipe, sal); among the latter are "lauric fats" derived from coconut and palm oils. Coatings made with these ingredients are often called "nontempering" chocolates.

Modeling Chocolate "Modeling" or "molding" chocolate is a version made expressly for shaping into decorations. It's made by mixing molten chocolate with a third to half its weight of corn syrup and sugar, then kneading the mixture into a pliable ma.s.s. The resulting "chocolate" is now a concentrated sugar syrup that is filled and thickened with cocoa particles and droplets of cocoa b.u.t.ter. The pieces stiffen as the syrup phase loses moisture to the air and to the dry cocoa particles. "Modeling" or "molding" chocolate is a version made expressly for shaping into decorations. It's made by mixing molten chocolate with a third to half its weight of corn syrup and sugar, then kneading the mixture into a pliable ma.s.s. The resulting "chocolate" is now a concentrated sugar syrup that is filled and thickened with cocoa particles and droplets of cocoa b.u.t.ter. The pieces stiffen as the syrup phase loses moisture to the air and to the dry cocoa particles.

Chocolate and Health Fats and Antioxidants Cocoa beans, like all seeds, are rich in nutrients that support the plant embryo until it develops leaves and roots. They're especially rich in saturated fats, which are notorious for contributing to raised blood cholesterol levels and therefore to the risk of heart disease. However, much of the saturated fat in cocoa b.u.t.ter is a particular fatty acid that the body immediately converts into an unsaturated one (stearic acid is converted to oleic acid). So chocolate is not thought to pose a risk to the heart. In fact, it may well be beneficial. Cocoa particles are a tremendously rich source of antioxidant phenolic compounds, which account for 8% of the weight of cocoa powder. The higher the cocoa solids content of a chocolate or candy, the higher its antioxidant content. Any added sugar, milk products, or cocoa b.u.t.ter simply dilute the cocoa solids and their phenolics. The dutching process also reduces the levels of desirable phenolics in cocoa powder, and the milk proteins in milk chocolate appear to bind to the same molecules and prevent us from absorbing them. Cocoa beans, like all seeds, are rich in nutrients that support the plant embryo until it develops leaves and roots. They're especially rich in saturated fats, which are notorious for contributing to raised blood cholesterol levels and therefore to the risk of heart disease. However, much of the saturated fat in cocoa b.u.t.ter is a particular fatty acid that the body immediately converts into an unsaturated one (stearic acid is converted to oleic acid). So chocolate is not thought to pose a risk to the heart. In fact, it may well be beneficial. Cocoa particles are a tremendously rich source of antioxidant phenolic compounds, which account for 8% of the weight of cocoa powder. The higher the cocoa solids content of a chocolate or candy, the higher its antioxidant content. Any added sugar, milk products, or cocoa b.u.t.ter simply dilute the cocoa solids and their phenolics. The dutching process also reduces the levels of desirable phenolics in cocoa powder, and the milk proteins in milk chocolate appear to bind to the same molecules and prevent us from absorbing them.

Caffeine and Theobromine Chocolate contains two related alkaloids, theobromine and caffeine, in the ratio of about 10 to 1. Theobromine is a weaker stimulant of the nervous system than caffeine is (p. 433); its main effect seems to be a diuretic one. (However it is quite toxic to dogs, who can suffer serious poisoning from chocolate candies.) A 1-oz /30 gm piece of unsweetened chocolate contains around 30 mg of caffeine, around a third the dose in a cup of coffee; sweetened and milk chocolates contain substantially less. Cocoa powder has around 20 mg caffeine per tablespoon/10 g. Chocolate contains two related alkaloids, theobromine and caffeine, in the ratio of about 10 to 1. Theobromine is a weaker stimulant of the nervous system than caffeine is (p. 433); its main effect seems to be a diuretic one. (However it is quite toxic to dogs, who can suffer serious poisoning from chocolate candies.) A 1-oz /30 gm piece of unsweetened chocolate contains around 30 mg of caffeine, around a third the dose in a cup of coffee; sweetened and milk chocolates contain substantially less. Cocoa powder has around 20 mg caffeine per tablespoon/10 g.

Cravings for Chocolate Because many people, especially women, experience cravings for chocolate that border on the symptoms of addiction, it has been thought that chocolate might contain psychoactive chemicals. Chocolate does turn out to contain both "cannabinoid" chemicals - chemicals similar to the active ingredient in marijuana - as well as other molecules that cause brain cells to acc.u.mulate cannabinoid chemicals. But these are present in extremely small amounts that probably have no practical significance. Similarly, chocolate contains phenylethylamine, a naturally occurring body chemical that has amphetamine-like effects - but then so do sausages and other fermented foods. In fact there is good experimental evidence that chocolate does not contain any drug-like substances capable of inducing a true addiction. Psychologists have shown that chocolate cravings can be satisfied by imitations that have no real chocolate in them, while these cravings are not satisfied by capsules of genuine cocoa powder or chocolate that are swallowed without tasting. It appears to be the sensory experience of eating chocolate, no more and no less, that is powerfully appealing. Because many people, especially women, experience cravings for chocolate that border on the symptoms of addiction, it has been thought that chocolate might contain psychoactive chemicals. Chocolate does turn out to contain both "cannabinoid" chemicals - chemicals similar to the active ingredient in marijuana - as well as other molecules that cause brain cells to acc.u.mulate cannabinoid chemicals. But these are present in extremely small amounts that probably have no practical significance. Similarly, chocolate contains phenylethylamine, a naturally occurring body chemical that has amphetamine-like effects - but then so do sausages and other fermented foods. In fact there is good experimental evidence that chocolate does not contain any drug-like substances capable of inducing a true addiction. Psychologists have shown that chocolate cravings can be satisfied by imitations that have no real chocolate in them, while these cravings are not satisfied by capsules of genuine cocoa powder or chocolate that are swallowed without tasting. It appears to be the sensory experience of eating chocolate, no more and no less, that is powerfully appealing.

Chapter 13.

Wine, Beer, and Distilled Spirits

The Nature of Alcohol Yeasts and Alcoholic FermentationThe Qualities of AlcoholAlcohol as a Drug: IntoxicationHow the Body Metabolizes AlcoholCooking with AlcoholAlcoholic Liquids and Wood Barrels Wine The History of WineWine GrapesMaking WineSpecial WinesStoring and Serving WineEnjoying Wine Beer The Evolution of BeerBrewing Ingredients: MaltBrewing Ingredients: HopsBrewing BeerStoring and Serving BeerKinds and Qualities of Beer Asian Rice Alcohols: Chinese Chiu Chiu and j.a.panese and j.a.panese Sake Sake Sweet Moldy GrainsStarch-Digesting MoldsBrewing Rice Alcohols Distilled Spirits The History of Distilled SpiritsMaking Distilled AlcoholsServing and Enjoying SpiritsKinds of Spirits Vinegar An Ancient IngredientThe Virtues of Acetic AcidThe Acetic FermentationVinegar ProductionCommon Kinds of VinegarBalsamic VinegarSherry Vinegar Like all good foods, wine, beer, and spirits nourish and satisfy the body. What sets them apart is the very direct way in which they touch the mind. They contain alcohol, which is both a source of energy and a drug. In moderate amounts, alcohol causes us to feel and express emotions of all kinds - happiness, conviviality, sadness, anger - with more freedom. In large amounts, it's a narcotic: it numbs feeling and clouds thought. Alcoholic drinks thus offer various degrees of release from our usual state of mind. Small wonder that they were once considered an earthly version of the nectar of the G.o.ds, foods that give mortals a taste of being carefree masters of life!

Humankind has always had a thirst for alcohol, and now satisfies it with ma.s.s-produced drinks that offer an inexpensive respite from the world and its cares. But some wines and beers and spirits are among the most finely crafted foods there are, the best that the world and care have to offer. Their flavor can be so rich, balanced, dynamic, and persistent that they touch the mind not with release from the world, but with a heightened attentiveness and connection to it.

Wine, beer, and spirits are the creation of microscopic yeasts, which break food sugars down into alcohol molecules. Alcohol is a volatile substance whose own aroma is relatively diffuse. It has the effect of lending a new dimension to the flavor of grapes and grains, a kind of open stage on which the food's own volatile molecules can appear. Yeasts are also prodigious flavor chemists, so during the fermentation they fill that stage with dozens of new aromas. The winemaker or brewer then directs the transformation of this teeming, unruly cast into a balanced, harmonious ensemble.

Though they share this basic nature, wine and beer and spirits are very different foods. Wine begins with fruits that are fragrant and sweet with sugars, and therefore ready-made to ferment into an aromatic drink - but only during the few days of the year when they're ripe. Grapes and wine are a gift of nature, a form of grace, which the winemaker must accept when they're given, and can leave largely to themselves to realize their innate potential for producing flavor. Beer and rice alcohols, by contrast, are the expression of everyday human effort and ingenuity. They're made from sugarless, aroma-less dry grains, the charmless but dependable staff of life. Brewers transform grains into something fermentable and aromatic by sprouting them or cultivating molds on them for days, and cooking them for hours. They can do this at any time of the year, anywhere in the world. Beer is thus our universal alcohol, comfortably local and everyday and ordinary, yet sometimes extraordinary. And distilled spirits are the heart of wine and beer, concentrates of their volatile and aromatic content, and drinks of unmatched intensity.

The pleasure of tasting a good beer or wine or spirit grows with the recognition that its flavor is the expression of many natural, cultural, and personal particulars: a place and its traditions, certain plants and the soil they grew in, a year and its weather, the course of fermentation and maturation, the taste and skills of the maker. Their rich natural and human parentage explains why alcohols are so absorbingly diverse, and why a thoughtful sip can momentarily fill us with the world and delight.

The Drink of HappinessNearly 4,000 years ago, a Sumerian poet put these words into the mouth of the G.o.ddess Inanna, who ruled both heaven and earth and was as delighted as any mortal by the experience of drinking beer. Ninkasi was the G.o.ddess of beer. (I've omitted the poem's many repet.i.tions.)May Ninkasi live together with you!Let her pour for you beer [and] wine,Let [the pouring] of the sweet liquor resoundpleasantly for you!In the...reed buckets there is sweet beer,I will make cupbearers, boys, [and]brewers stand by,While I circle around the abundance of beer,While I feel wonderful, I feel wonderful,Drinking beer, in a blissful mood,Drinking liquor, feeling exhilarated,With joy in the heart [and] a happy liver -While my heart full of joy,[And] [my] happy liver I cover with agarment fit for a queen!The heart of Inanna is happy again,The heart of the queen of heaven is happy again!- Transl. Miguel Civil The Nature of Alcohol Alcohol molecules are made in many living cells as a by-product of breaking down sugar molecules for their chemical energy. Most cells then break down the alcohol molecules to extract their energy content too. The great exception to this rule is certain yeasts, which excrete alcohol into their surroundings. Like the lactic acid in cheeses and pickled vegetables, like the powerful aromas in herbs and spices, the alcohol in wine and beer is a defensive chemical weapon, which the yeasts deploy to protect themselves against compet.i.tion from other microbes. Alcohol is toxic to living cells. Even the yeasts that make it for us can only tolerate a certain amount. The pleasant feeling that it gives us is a manifestation of the fact that it's disrupting the normal function of our brain cells.

Yeast. Cells of brewer's yeast, Saccharomyces cerevisiae, Saccharomyces cerevisiae, as seen through an electron microscope. Each is about 0.005 mm in diameter. The cell at the upper right center is in the process of reproducing, and bears the scars of previous buddings. as seen through an electron microscope. Each is about 0.005 mm in diameter. The cell at the upper right center is in the process of reproducing, and bears the scars of previous buddings.

Yeasts and Alcoholic Fermentation Yeasts are a group of about 160 species of single-celled microscopic molds. Not all are useful: some cause the spoilage of fruits and vegetables, some cause human disease (for example, the yeast infection of Candida albicans Candida albicans). Most of the yeasts used in making bread and alcoholic drinks are members of the genus Saccharomyces, Saccharomyces, whose name means "sugar fungus." We cultivate them for the same reason that we use particular bacteria to sour milk: they make foods resistant to infection by other microbes, and produce substances that are mainly pleasant to us. Essential to the yeasts' production of alcohol is their ability to survive on very little oxygen, which most living cells use to burn fuel molecules for energy, leaving behind only carbon dioxide and water. In the absence of oxygen, the fuel can be broken down only partly. The overall equation for the production of energy from glucose without oxygen goes like this: whose name means "sugar fungus." We cultivate them for the same reason that we use particular bacteria to sour milk: they make foods resistant to infection by other microbes, and produce substances that are mainly pleasant to us. Essential to the yeasts' production of alcohol is their ability to survive on very little oxygen, which most living cells use to burn fuel molecules for energy, leaving behind only carbon dioxide and water. In the absence of oxygen, the fuel can be broken down only partly. The overall equation for the production of energy from glucose without oxygen goes like this: C6H12O6[image] 2CH 2CH3CH2OH + 2CO2 + energy + energy Glucose[image] alcohol + carbon dioxide + energy alcohol + carbon dioxide + energy Yeasts introduce a variety of other compounds into the grape juice or grain mash that contributes characteristic flavors. For example, they produce savory succinic acid, and transform amino acids in the liquid into "higher," or longer-chain alcohols; they combine alcohols with acids to make fruity-smelling esters; they produce sulfur compounds reminiscent of cooked vegetables, coffee, and toast. And when a yeast cell dies, its enzymatic machinery digests the cell and releases its contents into the liquid, where they continue to generate flavor. Because growing yeast cells synthesize proteins and B vitamins, they can actually make a fruit juice or cereal mash more nutritious than it was when fresh.

The Qualities of Alcohol In chemistry, the term alcohol alcohol is applied to a large family of substances with a similar molecular structure. Our everyday word is applied to a large family of substances with a similar molecular structure. Our everyday word alcohol alcohol refers to one particular member of this family, which chemists call refers to one particular member of this family, which chemists call ethyl alcohol, ethyl alcohol, or or ethanol. ethanol. In this chapter I'll use In this chapter I'll use alcohol alcohol in its common sense, but I'll also refer to "higher" alcohols, or molecules in the alcohol family with more atoms than ethanol has. in its common sense, but I'll also refer to "higher" alcohols, or molecules in the alcohol family with more atoms than ethanol has.

Ethanol, or common alcohol. The versatile ethanol molecule has one end that resembles the fatty-acid carbon chain of fats and oils, and one end that resembles water.

Alcoholic Fermentation Helped Form Modern BiologyThe mystery of fermentation attracted some of the best and most headstrong scientists of the 19th century, including Justus von Liebig and Louis Pasteur, and helped give rise to the science of microbiology. The first microorganisms to be isolated in pure cultures were beer and wine yeasts prepared in the laboratory of the Carlsberg Brewery in Copenhagen around 1880. And scientists coined the word enzyme, enzyme, denoting the remarkable protein molecules that living cells use to transform other molecules, from the Greek words for "in yeast," where sugar is transformed into alcohol. denoting the remarkable protein molecules that living cells use to transform other molecules, from the Greek words for "in yeast," where sugar is transformed into alcohol.

Physical and Chemical Qualities Pure alcohol is a clear, colorless liquid. The alcohol molecule is a small one, CH Pure alcohol is a clear, colorless liquid. The alcohol molecule is a small one, CH3CH2OH, whose backbone is just two carbon atoms. One end of the alcohol molecule, the CH3, resembles fats and oils, while the OH group at the other end is two-thirds of a water molecule. Alcohol is therefore a versatile liquid. It mixes easily with water, but also with fatty substances, including cell membranes, which it excels at penetrating, and aroma molecules and carotenoid pigments, which it excels at extracting from cells. The higher alcohols, which yeasts also produce in small quant.i.ties and which become concentrated in distilled spirits, have a longer fat-like end to their molecules (p. 762), and behave more like fats. They lend an oily, viscous quality to whiskies and other spirits. They also tend to concentrate in the membranes of our cells, and therefore are more irritating and more potent narcotics than simple alcohol.

Several of alcohol's physical properties have important consequences for the cook and food lover.

Alcohol is more volatile than water, more easily evaporated and brought to the boil. Its low boiling point, 176F/78C, is what makes it possible to distill alcohol into a much stronger solution than wine or beer.

Alcohol is flammable, which makes possible spectacular flaming dishes fueled by brandy or rum. The food doesn't get scorched because the heat of combustion is fully absorbed by the vaporization of the spirits' water.

Alcohol has a much lower freezing point than water, 173F/114C. This makes it possible to concentrate alcoholic liquids in winter cold or the freezer (see box, p. 761).

A given volume of alcohol weighs 80% as much as the same volume of water, so a mixture of alcohol and water is lighter than pure water. This helps makes possible layered c.o.c.ktails (see box, p. 770).

Alcohol and Flavor We experience the presence of alcohol in a food through our senses of taste, smell, and touch. The alcohol molecule bears some resemblance to a sugar molecule, and indeed it has a slightly sweet taste. At high concentrations, those typical of distilled spirits and even some strong wines, alcohol is irritating, and produces a pungent, "hot" sensation in the mouth, as well as in the nose. As a volatile chemical, alcohol has its own distinctive aroma, which we experience at its purest in unflavored grain alcohol or vodka. Its chemical compatibility with other aroma compounds means that concentrated alcohol tends to bind aromas in foods and drinks and inhibit their release into the air. But at very low concentrations, around 1% or less, alcohol actually enhances the release of fruity esters and other aroma molecules into the air. This is one reason that wine, vodka, and other alcohols are valuable ingredients in general cooking, provided that the proportion is small or the alcohol mostly removed by long cooking. We experience the presence of alcohol in a food through our senses of taste, smell, and touch. The alcohol molecule bears some resemblance to a sugar molecule, and indeed it has a slightly sweet taste. At high concentrations, those typical of distilled spirits and even some strong wines, alcohol is irritating, and produces a pungent, "hot" sensation in the mouth, as well as in the nose. As a volatile chemical, alcohol has its own distinctive aroma, which we experience at its purest in unflavored grain alcohol or vodka. Its chemical compatibility with other aroma compounds means that concentrated alcohol tends to bind aromas in foods and drinks and inhibit their release into the air. But at very low concentrations, around 1% or less, alcohol actually enhances the release of fruity esters and other aroma molecules into the air. This is one reason that wine, vodka, and other alcohols are valuable ingredients in general cooking, provided that the proportion is small or the alcohol mostly removed by long cooking.

The Tears of Strong Wine and SpiritsRegular drinkers of strong wines and spirits have probably mused upon the odd phenomenon known as "tears" or "legs," films of liquid on the inside of the gla.s.s that seem to be in slow but constant movement up and down. These moving films are created by the dynamic nature of alcohol-water mixtures. Alcohol lowers the forces of attraction between water molecules in wine or spirits; but at the edge of the surface, alcohol evaporates from the water, the water bonds more strongly to itself and to the gla.s.s, and the decreasingly alcoholic water pulls itself up the side of the gla.s.s until gravity wins out and it falls back in a droplet. The higher the alcoholic content of the liquid, and the easier it is for alcohol to evaporate - warm temperatures and wide-mouthed shallow gla.s.ses are most favorable - the more p.r.o.nounced the tears and legs are.

Effects on Living Things One consequence of alcohol's chemical versatility is that it readily penetrates the membranes of living cells, which are made in part of fat-like molecules. When it does so, it disturbs the action of the membrane proteins. A high enough concentration of alcohol will cause such a disturbance that this critical boundary between cell and environment fails, and the cell dies. The yeasts that produce alcohol can tolerate a concentration of about 20%, and most other microbes are killed by much less. When the solution also contains acid or sugar, as in wines, alcohol is an even more effective microbial poison. This is why, unlike beer and wine, distilled spirits and such alcohol-fortified wines as sherry and port don't spoil after they're opened. One consequence of alcohol's chemical versatility is that it readily penetrates the membranes of living cells, which are made in part of fat-like molecules. When it does so, it disturbs the action of the membrane proteins. A high enough concentration of alcohol will cause such a disturbance that this critical boundary between cell and environment fails, and the cell dies. The yeasts that produce alcohol can tolerate a concentration of about 20%, and most other microbes are killed by much less. When the solution also contains acid or sugar, as in wines, alcohol is an even more effective microbial poison. This is why, unlike beer and wine, distilled spirits and such alcohol-fortified wines as sherry and port don't spoil after they're opened.

Our own pleasant inebriation when we drink alcohol is in part a symptom of mild membrane and protein disturbance throughout our nervous system.

Alcohol as a Drug: Intoxication Alcohol is a drug drug: it alters the operation of the various tissues into which it diffuses. We value it most for its influence on the central nervous system, where it acts as a narcotic. The fact that it seems to stimulate more animated, excited behavior than usual is actually a symptom of its depressant effect on the higher functions of the brain, those that normally control our behavior with various kinds of inhibition. As more alcohol reaches the brain, it interferes with more basic processes: memory, concentration, and thinking in general; muscular coordination, speech, vision. With regard to the idea that alcohol is an aphrodisiac, modern investigators continue to cite the authority of the Porter in Shakespeare's Macbeth Macbeth, who says of drink that "Lechery, sir, it provokes, and unprovokes: it provokes the desire, but it takes away the performance."

The degree to which someone is intoxicated depends on the concentration of alcohol in the cells. Once alcohol is absorbed from the digestive tract, the blood rapidly distributes it to all body fluids, and it readily diffuses into and across membranes to penetrate all cells. Large people can therefore drink more than small people without being drunker: they have a greater volume of body fluids and cells in which to dilute the alcohol. Impaired coordination and impulsive behavior usually appear when the concentration of alcohol in the blood is 0.020.03%. Falling-over drunkenness is the result at 0.15%, and 0.4% can be fatal.

As drugs go, alcohol is a relatively weak one. It takes grams of pure alcohol, not milligrams, to have noticeable effects, and this allows us to enjoy moderate amounts of wine and beer without harming ourselves. But like other narcotic drugs, alcohol can be addictive, and the habitual consumption of large quant.i.ties is destructive. It has been the cause of widespread misery and premature death for thousands of years, and it still is. Alcohol and the molecule to which it's first metabolized, acetalde-hyde, disrupt many systems and organs in the body. Their constant presence can therefore cause a broad range of serious and even fatal diseases.

The Source of Happiness and Oblivion.o.bservers of the human condition have long remarked on the ways in which alcohol helps people deal with that condition. Here are two of the earliest and simplest formulations, from the Ayurvedic tradition of India, and from the Old Testament.Wine is the foremost of all things that lead to cheerfulness.Abuse of wine is the foremost of all causes that lead to loss of intelligence and memory.- Charaka-Samhita, Charaka-Samhita, ca. 400 ca. 400 BCE BCEGive strong drink unto him that is ready to perish, and wine unto them that be of heavy hearts. Let him drink, and forget his poverty, and remember his misery no more.- Proverbs, ca. 500 BCE BCE How the Body Metabolizes Alcohol Our bodies eliminate alcohol by breaking it down in a series of chemical reactions and using the energy freed by those reactions. Alcohol's chemical structure has similarities to both sugar and fat, and it has a nutritional value between the two, around 7 calories per gram (sugar has 4 calories per gram, fat 9). It provides around 5% of the calories in the American diet, much more among heavy drinkers.

Alcohol is broken down and converted into energy in two organs, the stomach and the liver. The "first-pa.s.s" metabolism of alcohol in the stomach consumes a portion before it gets to the small intestine and then into the blood. That portion is around 30% in men, but only 10% in women. Men therefore experience a slower rise in blood alcohol when they drink, and can drink more before they feel its effects. And there are strong genetic influences on how well individuals are able to handle alcohol.

Overall, the body can metabolize around 1015 grams of alcohol per hour, the equivalent of one standard-sized drink every 6090 minutes. The level of alcohol in the blood reaches a maximum 3060 minutes after consumption. Foods, and especially fats and oils, delay the pa.s.sage of the stomach's contents into the small intestine, giving the stomach enzymes more time to work, slowing the rise in blood alcohol, and reducing its peak to about half of what it reaches on an empty stomach. On the other hand, aspirin interferes with the stomach's alcohol metabolism and so causes a quicker rise in blood alcohol levels. The carbon dioxide bubbles in sparkling wines and beer cause the same accelerated rise by as yet unknown means.

The Benefits of Moderate DrinkingOne consistent finding from several decades' worth of studies is that people who regularly consume the equivalent of one or two alcoholic drinks per day die less often from heart disease and stroke. (Higher consumption is a.s.sociated with higher death rates from cancer and accidents.) Alcohol itself raises the levels of desirable HDL cholesterol and lowers the levels of blood factors that induce clotting and thus contribute to blockages. And red wine and dark beer are good sources of antioxidant phenolic compounds (p. 255). Wine phenolics also cause arteries to widen and reduce the tendency of red blood cells to stick together, and a few of these compounds, notably resveratrol resveratrol and its relatives, inhibit an enzyme (cyclooxygenase) that's a.s.sociated with damaging inflammation reactions and the development of arthritis and certain cancers. and its relatives, inhibit an enzyme (cyclooxygenase) that's a.s.sociated with damaging inflammation reactions and the development of arthritis and certain cancers.

The Hangover Then there's the misery of the hangover, the general feeling of illness that we wake up with the morning after we've had too much alcohol. The folk remedies for this affliction are many and ancient. In medieval times, the medical school of Salerno was already recommending the hair of the dog: Then there's the misery of the hangover, the general feeling of illness that we wake up with the morning after we've had too much alcohol. The folk remedies for this affliction are many and ancient. In medieval times, the medical school of Salerno was already recommending the hair of the dog: Si nocturna tibi noceat potatio vini,Hoc tu mane bibas iterum, et fuerit medicina.If an evening of wine does you in,More the next morning will be medicine.

The hangover is in part a mild withdrawal syndrome. The night before, the body adjusted to a high concentration of alcohol and related narcotic chemicals, but by morning the drug is going or gone. Hyper-sensitivity to sound and light, for example, may be a leftover compensation for the general depression of the nervous system. The logic of the morning-after drink is simple but insidious: it restores many of the conditions to which the body had become accustomed, as well as lightly anesthetizing it. But this only postpones the body's true recovery from intoxication.

Only a few of the different symptoms that const.i.tute a hangover can be directly treated. The dry mouth and headache can be due to the dehydration that alcohol causes, so that drinking liquids may relieve them. Alcohol can also cause a headache by enlarging the cranial blood vessels; the caffeine in coffee and tea has the opposite effect, and may bring some relief.

Cooking with Alcohol Cooks use wines, beers, and distilled spirits as ingredients in a broad range of dishes, from savory soups and sauces and stews to sweet creams and cakes, souffles and sorbets. They contribute distinctive flavors, often including acidity, sweetness, and savoriness (from glutamic and succinic acids), and the aromatic dimension provided by alcohol and other volatile substances. Some qualities can be a challenge for the cook to work with, including the astringency of red wines (p. 737) and the bitterness of most beers. The alcohol itself also provides a third kind of liquid - in addition to water and oil - into which flavor and color molecules can be extracted and dissolved, as well as reactive molecules that can combine with other substances in the food to generate new aromas and greater depth of flavor. While large amounts of alcohol tend to trap other volatile molecules in the food, small traces boost their volatility and so intensify aroma.

At the same time that alcohol itself can be an a.s.set for the cook, it can also be a liability. Alcohol has its own pungent, slightly medicinal qualities, and these qualities are heightened and can become harsh in hot foods. Cooks may therefore simmer or boil sauces for some time to evaporate off as much alcohol as possible. In the showy preparation called the flambe, flambe, from the French for "to flame," they ignite the heated vapors of spirits and high-alcohol wines into flickering, ghostly blue flames to burn off the alcohol and give a lightly singed flavor to a dish. However, none of these techniques leave a food free of alcohol. Experiments have shown that long-simmered stews retain about 5% of the alcohol initially added, briefly cooked dishes from 10 to 50%, and flambes as much as 75%. from the French for "to flame," they ignite the heated vapors of spirits and high-alcohol wines into flickering, ghostly blue flames to burn off the alcohol and give a lightly singed flavor to a dish. However, none of these techniques leave a food free of alcohol. Experiments have shown that long-simmered stews retain about 5% of the alcohol initially added, briefly cooked dishes from 10 to 50%, and flambes as much as 75%.

Alcoholic Liquids and Wood Barrels The great good fortune of wine and beer is that microbes can "spoil" fruit juice and gruel into something both delicious and pleasantly inebriating. A few centuries ago, winemakers and distillers discovered another remarkable piece of good luck: simply storing wine, spirits, and vinegars in wood barrels turns out to give them a new and complementary dimension of flavor.

Oak and Its Qualities Though chestnut and cedar have been used in Europe and redwood in the United States, most barrels for aging wines and spirits are made from oak. Oak heartwood, the older inner wood, is a ma.s.s of dead cells that supports the outer living layers. The heartwood cells are filled with compounds that deter boring insects. These are mainly tannins, but they include such aromatic compounds as clove-like eugenol, vanilla-like vanillin, and oaky "oak lactones," relatives of the characteristic aromatics of coconut and peach. From 90 to 95% of the heartwood solids are cell-wall molecules, cellulose, hemicellulose, and lignin. These are mostly insoluble, but the lignins can be partly broken down and extracted by strong alcohol, and all can be transformed into new aromatic molecules when the wood is heated during barrel making (p. 449). Though chestnut and cedar have been used in Europe and redwood in the United States, most barrels for aging wines and spirits are made from oak. Oak heartwood, the older inner wood, is a ma.s.s of dead cells that supports the outer living layers. The heartwood cells are filled with compounds that deter boring insects. These are mainly tannins, but they include such aromatic compounds as clove-like eugenol, vanilla-like vanillin, and oaky "oak lactones," relatives of the characteristic aromatics of coconut and peach. From 90 to 95% of the heartwood solids are cell-wall molecules, cellulose, hemicellulose, and lignin. These are mostly insoluble, but the lignins can be partly broken down and extracted by strong alcohol, and all can be transformed into new aromatic molecules when the wood is heated during barrel making (p. 449).

Coopers rely mainly on two European oak species (Quercus robur and and Q. sessilis Q. sessilis), and ten North American species, the most important being the white oak (Q. alba). The European species are mostly made into wine barrels, American oak into barrels for aging distilled spirits. American oak tends to have lower levels of extractable tannins and higher levels of the oak lactones and vanillin.

Making Barrels: Forming and Cooking In order to make barrels, the cooper splits the heartwood into pieces, dries them, and forms them into thin, elongated staves, which are then roughly hooped together and heated to make them more pliable and easily bent into the final barrel shape. In Europe, the barrel interior is heated with a small brazier of burning wood sc.r.a.ps to 400F/200C. Once the softened staves have been tightly hooped into their final positions, the interior is "toasted" further at 300400F/150200C, for 5 to 20 minutes, depending on the degree of cooking desired: less for wine barrels, more for spirits. In the United States, the heat treatment for whiskey barrels is more extreme. The hooped staves are first steamed to soften them, and then the barrel interior is charred with an open gas burner for from 15 to 45 seconds. In order to make barrels, the cooper splits the heartwood into pieces, dries them, and forms them into thin, elongated staves, which are then roughly hooped together and heated to make them more pliable and easily bent into the final barrel shape. In Europe, the barrel interior is heated with a small brazier of burning wood sc.r.a.ps to 400F/200C. Once the softened staves have been tightly hooped into their final positions, the interior is "toasted" further at 300400F/150200C, for 5 to 20 minutes, depending on the degree of cooking desired: less for wine barrels, more for spirits. In the United States, the heat treatment for whiskey barrels is more extreme. The hooped staves are first steamed to soften them, and then the barrel interior is charred with an open gas burner for from 15 to 45 seconds.

Barrel Flavors Several things happen when alcoholic liquids are stored in new barrels. First, the liquid extracts soluble materials that contribute color and flavor, including tannins, oak and clove and vanilla aromas, and the sugars, browning-reaction products, and smoky volatiles formed when the barrel was heated. In the charred American barrels used for whiskey, the carbonized surface acts something like an activated charcoal absorbant, removing some materials from the whiskey and so accelerating the maturation of its flavor. Gaps and pores in the wood allow the liquid to absorb limited amounts of oxygen. And the rich chemical brew of wine or spirits, wood components, and oxygen slowly undergoes innumerable reactions and evolves toward a harmonious equilibrium. Several things happen when alcoholic liquids are stored in new barrels. First, the liquid extracts soluble materials that contribute color and flavor, including tannins, oak and clove and vanilla aromas, and the sugars, browning-reaction products, and smoky volatiles formed when the barrel was heated. In the charred American barrels used for whiskey, the carbonized surface acts something like an activated charcoal absorbant, removing some materials from the whiskey and so accelerating the maturation of its flavor. Gaps and pores in the wood allow the liquid to absorb limited amounts of oxygen. And the rich chemical brew of wine or spirits, wood components, and oxygen slowly undergoes innumerable reactions and evolves toward a harmonious equilibrium.

New oak barrels give a p.r.o.nounced flavor to liquids stored in them, one that can overwhelm the inherent qualities of delicate wines. The producer can control the contribution of the wood by limiting the aging time in new barrels, or by working with used barrels, which have already had much of their flavor components extracted.

Barrel FermentationSome wines and vinegars are fermented in the barrel as well as matured there after fermentation, and develop a distinctive barrel-fermented flavor. One unusual component of that flavor, produced by the action of yeast enzymes on compounds found in toasted oak, is a sulfur-containing chemical whose aroma is reminiscent of roasted coffee and roasted meat (furfurylthiol).

Alternatives to Barrels Oak barrels are expensive, so only relatively expensive wines and spirits are aged in them. There are other ways of getting oak flavor into less expensive products. Oak barrels are expensive, so only relatively expensive wines and spirits are aged in them. There are other ways of getting oak flavor into less expensive products. Boises, Boises, extracts made by boiling wood chips in water, are a traditional finis.h.i.+ng additive in French brandies, including Cognac and Armagnac. In recent years, large-volume winemakers have begun putting barrel staves, oak chips, and even sawdust into wines while they mature in containers made of steel and other inert materials. extracts made by boiling wood chips in water, are a traditional finis.h.i.+ng additive in French brandies, including Cognac and Armagnac. In recent years, large-volume winemakers have begun putting barrel staves, oak chips, and even sawdust into wines while they mature in containers made of steel and other inert materials.

Wine The juice of the grape is just one of the naturally sweet liquids with which our ancestors learned to make alcoholic drinks. Perhaps just as ancient as grape wine is koumiss, koumiss, the fermented mare's milk of the central Asian nomads. One Greek word for wine, the fermented mare's milk of the central Asian nomads. One Greek word for wine, methu, methu, came from the Indo-European word for fermented honey water, whose name in English is came from the Indo-European word for fermented honey water, whose name in English is mead. mead. The Romans fermented dates and figs. And before they tasted wine, the inhabitants of northern Europe drank apple juice fermented into cider. The Romans fermented dates and figs. And before they tasted wine, the inhabitants of northern Europe drank apple juice fermented into cider.

But the grape turned out to be uniquely suited to the development of a diverse family of alcoholic drinks. The grapevine is a highly productive plant that can adapt to a wide range of soils and climates. Its fruits retain large amounts of an unusual acid, tartaric acid, which few microbes can metabolize, and which favors the growth of yeasts. The grapes ripen with enough sugar that the yeasts' alcohol production can suppress the growth of nearly all other microbes. And they offer striking colors and a variety of flavors.

Thanks largely to these qualities, grapes are the world's largest fruit crop, with about 70% of the annual production used to make wine. France, Italy, and Spain are the world's largest wine producers and exporters.

The History of Wine The evolution of wine is long and fascinating, and ongoing. Here are a few highlights.