What Einstein Kept Under His Hat: Secrets of Science in the Kitchen by Robert L. Wolke Page B
Authors: Robert L. Wolke
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firmness, ranging from soft spreaders to bread shredders.
Enter the wee little beasties. Several breeds of bacteria, some good for us and some bad, view milk sugar (lactose) as yummy victuals and will thrive in cream if we let them. The bad ones can be knocked off by pasteurization, while the good ones can be encouraged by warm temperatures to go ahead and nosh, generating some wonderfully flavorful by-products as they do. Both of these measures have important consequences for the butter.
In the United States, all cream used to make commercial butter must first be pasteurized by being held at 165°F (74°C) for 30 minutes, a process that connoisseurs insist imparts a slightly cooked, off flavor compared with down-on-the-farm, unpasteurized butter. In the best of all possible worlds, though regrettably not very often in our part of the world, the cream will then be cultured (or “ripened,” “matured,” or “soured”) by the addition of bacteria, usually a mixture of Lactococcus and Leuconostoc strains, which produce lactic acid and diacetyl. Lactic acid adds a pleasant tang to butter, while diacetyl is the chemical that gives butter its most prominent characteristic flavor. Unfortunately, most American mass producers of butter (at up to 8,000 pounds per batch) skip the time-consuming culturing step.
By this time you have figured out that butter froths up in the sauté pan because its water turns to steam, which then bubbles its way out noisily. But in spite of its high water content, hot butter doesn’t spatter in the pan as other hot fats do in the presence of water. Instead, the butter merely foams up around the food. That’s because butter’s water is in the form of individual, microscopic globules. They don’t join together into droplets that, in contact with hot fat, would explode into relatively large bursts of steam, carrying spatters of hot fat along with them.
How, then, does butter homogenize and thicken a pan sauce? In two ways. First, butter’s fat content can absorb the fat in the pan while its water content can absorb the wine or stock, thus bringing them into a sort of matrimonial harmony. But the marriage wouldn’t last very long if the butter didn’t contain a small amount (about 0.24 percent) of lecithin, an emulsifier. An emulsifier’s molecules stabilize an emulsion by latching onto both fat molecules and water molecules at the same time, effectively keeping them together. (See p. 380.) When the entire contents of the pan have thus become a fat-and-water emulsion, the contents will obviously be thicker, glossier, and more unctuous than the watery wine or stock alone. French chefs ever since Escoffier have been finishing their pan sauces with une noisette of butter.
THE FOODIE’S FICTIONARY:
Acidophilus—the Escoffier of Greek cuisine
GOOD EGGS GET GOOD GRADES
There are so many kinds of eggs in my supermarket, I don’t know which to buy. They all seem to be Grade A, which I suppose is good, but what about size and freshness?
....
T he USDA grades eggs according to quality—not according to freshness—as AA, A, or B. To earn a grade of AA, an egg must have an air cell within the wide end that is less than an eighth of an inch (3 millimeters) deep; a shell that is well shaped and clean, with very few ridges or rough spots; and when the egg is broken onto a flat surface, a yolk that stands up high and domelike in the center of a clear, thick, and firm white.
Grades A and B fit these criteria slightly less rigorously. They may not look as pretty when fried or poached, because the yolks may be a bit flat and the whites a bit more runny, but they are perfectly fine for uses in which they won’t be served whole.
Submitting eggs for federal grading, however, is optional for the producers (the human ones, that is, not the hens). Eggs sold in cartons without the USDA shield will have been
Enter the wee little beasties. Several breeds of bacteria, some good for us and some bad, view milk sugar (lactose) as yummy victuals and will thrive in cream if we let them. The bad ones can be knocked off by pasteurization, while the good ones can be encouraged by warm temperatures to go ahead and nosh, generating some wonderfully flavorful by-products as they do. Both of these measures have important consequences for the butter.
In the United States, all cream used to make commercial butter must first be pasteurized by being held at 165°F (74°C) for 30 minutes, a process that connoisseurs insist imparts a slightly cooked, off flavor compared with down-on-the-farm, unpasteurized butter. In the best of all possible worlds, though regrettably not very often in our part of the world, the cream will then be cultured (or “ripened,” “matured,” or “soured”) by the addition of bacteria, usually a mixture of Lactococcus and Leuconostoc strains, which produce lactic acid and diacetyl. Lactic acid adds a pleasant tang to butter, while diacetyl is the chemical that gives butter its most prominent characteristic flavor. Unfortunately, most American mass producers of butter (at up to 8,000 pounds per batch) skip the time-consuming culturing step.
By this time you have figured out that butter froths up in the sauté pan because its water turns to steam, which then bubbles its way out noisily. But in spite of its high water content, hot butter doesn’t spatter in the pan as other hot fats do in the presence of water. Instead, the butter merely foams up around the food. That’s because butter’s water is in the form of individual, microscopic globules. They don’t join together into droplets that, in contact with hot fat, would explode into relatively large bursts of steam, carrying spatters of hot fat along with them.
How, then, does butter homogenize and thicken a pan sauce? In two ways. First, butter’s fat content can absorb the fat in the pan while its water content can absorb the wine or stock, thus bringing them into a sort of matrimonial harmony. But the marriage wouldn’t last very long if the butter didn’t contain a small amount (about 0.24 percent) of lecithin, an emulsifier. An emulsifier’s molecules stabilize an emulsion by latching onto both fat molecules and water molecules at the same time, effectively keeping them together. (See p. 380.) When the entire contents of the pan have thus become a fat-and-water emulsion, the contents will obviously be thicker, glossier, and more unctuous than the watery wine or stock alone. French chefs ever since Escoffier have been finishing their pan sauces with une noisette of butter.
THE FOODIE’S FICTIONARY:
Acidophilus—the Escoffier of Greek cuisine
GOOD EGGS GET GOOD GRADES
There are so many kinds of eggs in my supermarket, I don’t know which to buy. They all seem to be Grade A, which I suppose is good, but what about size and freshness?
....
T he USDA grades eggs according to quality—not according to freshness—as AA, A, or B. To earn a grade of AA, an egg must have an air cell within the wide end that is less than an eighth of an inch (3 millimeters) deep; a shell that is well shaped and clean, with very few ridges or rough spots; and when the egg is broken onto a flat surface, a yolk that stands up high and domelike in the center of a clear, thick, and firm white.
Grades A and B fit these criteria slightly less rigorously. They may not look as pretty when fried or poached, because the yolks may be a bit flat and the whites a bit more runny, but they are perfectly fine for uses in which they won’t be served whole.
Submitting eggs for federal grading, however, is optional for the producers (the human ones, that is, not the hens). Eggs sold in cartons without the USDA shield will have been
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