Part 6 (2/2)
First of all, how should we use it? Often, a sauce begins with the preparation of a roux. b.u.t.ter is melted over low heat, then flour is added, and the mixture is cooked for a long time at a temperature just high enough to make it bubble. When the roux becomes golden or deep brown, depending on the sauce, a flavorful liquid is added, and the mixture is slowly heated. The sauce thickens and cooks. Finally, it is skimmed, that is, it is finished by using absorbent paper toweling to soak up the fat that has floated to the surface and by heating it at length to eliminate the solid particles and excess flour.
Why Does Flour Thicken Sauces?
To answer this preliminary question, we must know that flour is composed of proteins and complex sugars that form small granules we call starch. Complex sugars? What do we mean by that? Something very simple. First of all, glucose is a little molecule that serves as fuel for animals as well as plants. Produced by the effect of the digestion of foods, the glucose molecule is circulated through our bodies by the blood. Energy is easily extracted from it by our cells, and, conversely, the molecule is easily regenerated.
Plant seeds especially need energy to develop. Thus plants store glucose in their seeds. Since it is soluble in water, however, glucose on its own would be leached away by the first rain, so it is chained together in long, less soluble molecules, sometimes straight (like amylose), sometimes branched (like amylopectin).
Thanks to weak links between the amylose molecules and the amylopectin molecules, the latter aggregate into small starch granules, between two- to fifty-thousandths of a millimeter in size. In some places, these groupings are orderly and the granules are crystalline. In other places, the granules are amorphous and more fragile.
If starch is useful in making sauces, it is because, heated, the energy of the water molecules is enough to disturb the amorphous areas and establish hydrogen bonds between the starch molecules and the water molecules. Water is gradually introduced into the granules, which swell, forming gels called starch (beginning at 60 to 65C [140 to 149F] for wheat flour as amylose molecules leak into the water).
Why does this thicken the solution? Because the amylose molecules that have pa.s.sed into the solution are surrounded by water molecules, and also because the swollen starch granules become ”microscopically enormous” and c.u.mbersome, making molecular motion difficult. The solution thus becomes viscous. And one final point: that viscosity is maximal when the temperature is kept between 79 and 96C (174 and 204F), not quite boiling.
Why Must Roux Be Cooked for a Long Time?
Amylose molecules have only weak thickening power and a floury taste. Thus, to avoid this taste, roux are cooked for a long time in b.u.t.ter before adding the liquid, to break down the amylose molecules into smaller sugars. Flour is an ideal product for the cook because it also contains proteins that react with the sugars through those Maillard reactions I have so frequently mentioned. Not only does cooking the roux eliminate the flour flavor, but in addition it produces odorant and tasty compounds.
If potato starch is used, the long cooking process becomes less important, because the amylose molecules, longer than those in wheat, have a less floury taste. Furthermore, potato starch jells at a lower temperature. It can be used to correct a too-fluid sauce at the last minute.
Why Must a Sauce Bound with Flour Not Be Overheated?
A sauce bound with flour must not be heated at too high a temperature, according to the cookbooks. After mixing the flour and liquid well, the preparation can cook but must not boil. Actually, once the sauce has attained its maximal viscosity, at about 93C (199F), it will reliquefy a bit if it boils.
Many conditions favor this reliquefication: heating for a long time after thickening, heating to the boiling point, and too vigorous physical agitation. In all these cases, the swollen granules are broken up into small fragments that flow better than large ones. In addition, a greater quant.i.ty of amylose then pa.s.ses into the solution. A network composed of a greater proportion of amylose is less rigid than one that is princ.i.p.ally formed from amylopectin, and the granules are less well maintained.
Why Must Sauces Bound with Flour Remain Liquid While They Are Cooking?
As a sauce bound with flour cools to below 38C (100F), the dispersed granules, already further separated by the amylose, begin to form a gel. When the mixture is cooled, the water and starch molecules have less and less energy, and hydrogen bonds begin to hold the molecules more and more securely, eventually reestablis.h.i.+ng those bonds that were initially responsible for the cohesion of the granules. The liquid hardens.
This effect should inspire cooks to make their roux-based sauces thinner than optimal for serving at the table. By the time they reach the table, they will inevitably have cooled and thickened.
The Skimming Skimming is a refined operation. It is the elimination of solid particles in the sauce (see the chapter ”Cooking”). Sauces bound with flour, especially, are improved by skimming off some of the solid particles of starch or the lumps formed during the sauce's preparation, as well as the flour proteins, which are not soluble in water. During the sauce's preparation, these proteins coagulate into little solid blocks that must be removed to achieve a perfectly uniform result worthy of Careme and the other great masters of French cooking.
If the famous French cook August Escoffier wanted manufacturers to introduce a gluten-free flour, it was specifically to avoid this long skimming operation. He was not entirely justified, because Maillard reactions, which require proteins, occur during the skimming and also because proteins cooked for a long time are dissociated into sapid amino acids.
In practice, a sauce is skimmed while it is heated, after it has been filtered, in a saucepan tilted in such a way that only one point on the bottom receives heat. Above this point, the sauce is hotter than elsewhere and thus lighter. It rises, and a current is established, with a plume ascending in the center and re-descent occurring on the periphery. As this happens, the solid particles follow the current but have the tendency to gather at the center of the saucepan and clump together. They only have to be skimmed periodically to eliminate them.
How Do We Salvage a Sauce that Is Too Thick or Thicken a Sauce that Is Too Thin?
Is the sauce you bound with flour too thick? Beat it vigorously, keeping a close eye on its viscosity. In this way you can break up the swollen granules until the sauce achieves a good consistency.
On the other hand, what to do if your sauce is too fluid? I can recommend beurre manie, a thickener of b.u.t.ter and flour worked together but not cooked. These two ingredients are mixed in equal amounts, and a little ball of the preparation is added to the sauce. The b.u.t.ter keeps the flour from lumping, so that it is gradually released into the sauce. This procedure is only a stopgap measure, however, because it does not avoid that floury taste. Thus it is a good idea to make your beurre manie from corn-rather than wheat-flour.
Why Must Some Fatty Substance Be Used in Sauces Bound with Flour?
Fats do not affect the viscosity of sauces bound with flour, but they affect the impression the sauce makes in the mouth. And, during the preparation of a roux, they coat the flour particles and keep them from lumping in the added liquid. Although their quant.i.ty can be limited, it seems difficult to eliminate them entirely.
Why Must Lemon Juice and Vinegar Be Avoided in Sauces with a Roux Base?
If lemon juice or vinegar are heated in the presence of amylose and amylopectin chains, they break down these chains into shorter ones that bind less well with water. The starch granules then gel and disintegrate at lower temperatures. For any given quant.i.ty of starch, the final product is less viscous.
A Burning Question Let Us Eat Well, We Will Die Fat Why do we like hot pepper, which burns? How can what is good be bad? Before turning to the pepper itself, let me enlarge on the question it poses for us: Is eating harmful?
Brillat-Savarin devoted a few juicy pages to the excesses of dining. Remember, this is his second aphorism: ”Animals feed themselves; men eat; but only wise men know the art of eating.”44 And his tenth: ”Men who stuff themselves and grow tipsy know neither how to eat nor how to drink.” And his tenth: ”Men who stuff themselves and grow tipsy know neither how to eat nor how to drink.”45 Very well. So eating or drinking too much is harmful. Today's doctors even try to specify which foods to avoid: certain animal fats, carbon and products of excessive combustion, nitrites used to salt meats ...
Nevertheless, the danger they see is truly everywhere. Chemists who study Maillard reactions (see page 27, for example), those universal reactions in cooking, find that they produce dangerous compounds of all kinds, and biologists are discovering that amanitoidin, the toxin in the white fungus phalloid amanita, is present in chanterelles and in most other edible mushrooms, though in minute quant.i.ties. We must conclude that the harm is in the excess, that it is the dose that makes the poison.
Does Hot Pepper Burn a Hole in the Stomach?
On the other hand, are the foods that seem harmful really harmful? Pepper, for example: is it as harmful as its effect on the tongue and mouth would lead us to imagine? A burning question that has, finally, just been studied empirically by doctors. David Graham, at the Veterans' Medical Center in Houston, Texas, used endoscopy to observe the effects of hot pepper on the stomach lining of twelve volunteers. He looked for possible inflammations after the absorption of meals peppered in various ways by lovers of highly spiced dishes.
During the first experiment, the volunteers were given a ”neutral” meal, consisting of steak and french fries. Then, on another day, they ate the same meal, but seasoned with aspirin (which has a reputation for puncturing the stomach). Finally, on a third occasion, pizza with spicy sausage and various Mexican foods were prepared for them, to which the medical team added as much hot pepper as most people can tolerate.
Endoscopy revealed that aspirin did indeed attack the stomach lining, but that hot pepper had no visible corrosive effect.
The princ.i.p.al pungent ingredient in hot pepper is capsaicin, a phenolic amide C18H22NO2 (or 8-methyl-N-vanniyl-6-neneamide). It stands to reason that this was the first ingredient to be studied. Its effect on the intestinal wall was compared to that of aspirin. Capsaicin had no visible effect. Neither did crushed red pepper deposited directly into the intestine with the help of a cannula. (or 8-methyl-N-vanniyl-6-neneamide). It stands to reason that this was the first ingredient to be studied. Its effect on the intestinal wall was compared to that of aspirin. Capsaicin had no visible effect. Neither did crushed red pepper deposited directly into the intestine with the help of a cannula.
On the other hand, Tabasco sauce deposited directly into the stomach produced an inflammation of the stomach lining. Why? Because it contains acetic acid; vinegar is a solution of acetic acid in water. In fact, the concentration of acetic acid in Tabasco is two times higher than the concentration of acetic acid in ordinary vinegar.
Thus, if red peppers stimulate nerve endings that register pain, especially in the mouth, they do not have an actual corrosive effect. They stimulate salivation, activate digestion, cause burning sensations in the a.n.u.s, and provide a feeling of well-being after a meal. Why? Perhaps because they stimulate the release of endogenous opioid substances, similar to morphine in their effect on the pain-sensitive nervous system.
So let us no longer be afraid to use hot pepper. Its fire will not consume us.
The Salad AN OASIS OF FRESHNESS.
Should the Salad Be Prepared in Advance?
Salad, with the vinaigrette that accompanies it, is a dish that the gourmand has never managed to fall in love with completely. It is a delicate, refres.h.i.+ng, and welcome complement to a big meal, but it ”kills” the wine because of its acidity. If you serve salad, give your guests only water to drink with it, and change mounts, as riders say, for the cheese and dessert courses. The salad interlude requires that a completely different wine follow the one you served with the meat.
How should a salad be prepared? We all think we know how: you wash the salad, add a vinaigrette dressing, and toss it.
Not so fast! Did you know that if you are serving a mixture of many different salad greens, you would be well advised to toss the toughest varieties first and then add the tender varieties? Did you know that the vinaigrette should not be added before you are ready to toss the salad? Did you know that vinaigrette is a different dressing depending on if there is more or less oil?
Vinaigrette Let us begin by examining the composition of the vinaigrette. We have seen with regard to mayonnaise that we achieve a mixture of oil and water by forming an emulsion, that is to say, a dispersion of oil droplets in water or, conversely, a dispersion of water droplets in oil. Composed of vinegar, oil, salt, pepper, and mustard to taste, a vinaigrette is just such an emulsion. The vinegar is a solution of acetic acid in water; the oil is ... the oil.
Normally, oil does not dissolve in water. It is only when a mixture of oil and water is vigorously agitated that the oil droplets achieve a suspension in the water. And this is only temporary, moreover, because these droplets, which are lighter than water, rise again to the surface, merge, and reform a separate oily phase.
Nevertheless, if the oil droplets are small enough, their separation is slowed, because their dispersion hampers the rising process. In addition, the mustard in vinaigrettes increases the stability of the emulsion: whisked into the vinaigrette at the same time as the oil droplets, its surface-active molecules bind to the oil molecules along their hydrophobic extremity and to the continuous, aqueous phase along their hydrophilic extremity. They thus form a link between the oil and the water.
This description only applies as long as the proportion of oil is not too great. When the water and oil are present in equal quant.i.ties, the oil forms droplets that disperse in the water because it has the tendency to form droplets. On the other hand, if the proportion of oil is increased, it is the water that will be dispersed in the form of droplets in the oil. In the presence of mustard, this transition takes place when the proportions exceed two parts of oil to one part of water.
In any case, these emulsions are more transient than a mayonnaise emulsion. Left to itself for a little while, a vinaigrette separates into vinegar at the bottom and oil on top.
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