BUTTER AND TRUE BUTTERMILK
Introduction
Salted versus Unsalted Butter: Some Historical Perspective
A Shopping and Handling Primer
Home-Churned Butter and Buttermilk: Sweet-Cream Type
Home-Churned Butter and Buttermilk: Ripened-Cream Type
Clarified Butters: A Revisionist View
European-Style Clarified Butter
Ghee (Indian Clarified Butter)
Nit’r Kibeh (Ethiopian Spiced Clarified Butter)
Beurre Manié
Flavored or Compound Butters: Some Suggestions
Beurre Blanc/Beurre Rouge
Beurre Noir/Beurre Noisette (“Black Butter”/“Brown Butter”)
About Butter-and-Egg Custards
Hollandaise Sauce
“Buttered Eggs” (Skillet-Custard Eggs)
Lemon Curd
About Butter in Pastry
Basic Pâte Brisée
Lemon Tart
Canadian Butter Tarts
Butter is one of life’s simple pleasures—except that nothing about it is simple but the eating. What you detect in even the most plebeian mass-produced cows’-milk butter has depths only half-fathomed by modern chemistry.
To get a small glimpse of the complexities beneath the surface, take about one or two tablespoons’ worth of cows’-milk butter—real 100 percent butter, not something dubbed “light butter” or “spreadable butter”—and plan to sample it at refrigerator temperature, room temperature, barely melted, briefly cooked, and resolidified. It can be salted or unsalted, but there should be no other added ingredients.
Start by unwrapping some cold butter and sniffing it. Depending on the individual batch, you may smell almost nothing or a tantalizing lactic quality without a name. Cut yourself four small pieces. A fraction of a tablespoon each will suffice. Watch the way the knife goes through the clean, cold, waxy substance. Return three pieces (and the stick they came from) to the refrigerator. Carve off a tiny bit of the fourth and put it in your mouth. Like the Cheshire Cat, it will vanish a little at a time, with a long, elusive finish. Eat another bit, trying to register the stages of smiling disappearance: waxy and solid, less solid but mysteriously cooling, more and more melted, nearly gone, gone but not forgotten. Different flavors will blossom in your mouth as all this unfolds. If your sample came from cultured butter, you may fleetingly think of crème fraîche or a soft red wine. If not, those notes will be missing; nonetheless, what you taste will echo what Henry James tasted in the words “summer afternoon.”
Now put the rest of the piece on a plate, and leave it in a warm room—close to 80°F, if possible—for an hour or two. Give it another sniff. Any prior aroma will be amplified. Nick off a bit to eat. This time the fatly glistening stuff will offer about as much resistance to the knife as face cream. You will recognize some of what you tasted before, but not the same progression of effects. The first sensation on the tongue will be close to greasiness, and the act of tasting will be somewhat truncated, as if some part of the original butter had just flown off into thin air. (It has.)
Now take one of the remaining chunks out of the refrigerator and prepare to just barely melt it. The best way is to start warming a little water in a small shallow pan, taking it off the heat when it is slightly hotter than lukewarm. Cut the butter into bits no larger than small peas and put it in a heatproof container like a glass custard cup or small measuring cup. Lower this into the pan of water and watch while the butter gradually melts. Don’t be in a rush; what you want to see is the moment at which the last identifiably solid bit is gone. Sniff and taste the butter from time to time while this is happening. The fragrance will become less delicate and perhaps almost cheesy. The marvelous fusion of nameless flavors will begin to come unglued, with a bland, oily taste poised against a faint sourness (how faint depends on the particular batch and how it was made). At the same time, you will see the butter resolving itself into clear fat and shoals of infinitesimal white flecks. When it is fully melted, some of the white parts will almost cloud over the top while some float toward the bottom.
Put the melted butter back into the refrigerator to chill until it is completely solid. Taste it a few times during this brief process. When it is hard and cold, take a good look and a good taste. It will never go back to what it was. You may be able to thaw and refreeze ice, or melt and recongeal an aspic. Nobody can do anything of the kind with butter. Once it has melted, its major components go their separate ways and can no more be put together again than Humpty Dumpty. As low as the melting temperature was (the last bits would have dissolved at about 99°F), your resolidified butter has lost the silky closeness and marble opacity of the original and is more like some congealed oil. It has a slightly coarse, grainy feel on the tongue, and a trace of sour whitish liquid may cling to the underside.
Now take another chunk of butter from the refrigerator and put it in a small heavy saucepan or skillet. Melt it on low heat, standing over the pan to observe everything as closely as possible. After the stage at which the last piece melted, the white flecks will start to swim around briskly and gather themselves into a sort of foam. Swirl the pan from time to time; stick in a spoon and carefully taste the hot butter once or twice. It will seem less and less recognizable as butter, but the kitchen will be filled with the deep, soul-warming smell that all right-thinking Americans once knew as “buttery.” You will see a little steam rising from the butter before the foam dies away. Another few seconds, and the white stuff—now easier to make out as separate specks—will start turning brown. Swirl the pan and take it off the heat just as the fat itself begins to change color, before everything careens down the slippery slope toward absolutely burned butter.
Spoon out a little and taste it, being careful not to burn yourself. The lightly browned fat will be still oilier than the batch you tasted at melting point. But the tiny brown scintillas will have a nutty sweetness unlike anything you’ve encountered in the earlier samples. Let it solidify at room temperature and taste it before briefly chilling it in the refrigerator and tasting it again. Both times you will find the texture still less whole—that is, grainier, more congealed, less waxy, and further from melt-in-the-mouth suavity—than the barely melted sample you tried before. And the browned bits will just reinforce the nonbutteriness, or ex-butteriness, of the flavor.
And now for something completely different: Take the fourth piece of butter and put it in a small lidded container. Find a good strong-tasting onion, cut off a slice, and put it in with the butter. Cover the container tightly and return it to the refrigerator for a day (or until you next remember it). Remove the lid and take out the onion before smelling and tasting the butter. It will have acquired a distinct onioniness that will remain until the end of its existence. The onion, on the other hand, won’t be in the least buttery.
COMPLEXITY COMPOUNDED
You have now proved something known to everyone who works with dairy products: No other food you can name exists in a state of more fragile chemical equilibrium—translating into flavor equilibrium—than butter and the milkfat from which it is made. The old superstitions about butter spoiling or not “coming” if somebody merely looked at it the wrong way aren’t far off the mark. It can hardly sit still for a minute without risking intervention from the universe at large. The agents of drastic, irreversible change are all around milkfat as soon as it is removed from the rest of the milk and chemically turned inside out by some form of churning. And the same is true whether the milk comes from a cow, goat, sheep, buffalo, or other animal.
Some of the potential changes are delightful, some ghastly. They would not occur if the chemist’s laboratory of the rumen and the finishing shop of the udder did not direct thousands of different substances into the milkfat, over and above those that go into the much less complex casein and whey. Butter is made up of so many components that some probably still don’t have names. The slightest shift in balance can mean an immense flavor difference. This incre
dible delicacy reflects the life-giving importance of milk itself.
Milkfat is the most concentrated source of energy for nurslings. And it is the crux of their first taste experience. As cooks know, fat is the soul of taste. Vegetable fats like olive or walnut oil impart their unmistakable note to anything cooked in them. But when it comes to milkfat—“butterfat” in its pre-butter state—flavor also plays a biological role. Every species of mammal, from mouse to rhinoceros, produces milk with a “lipid profile,” or mixture of fat components, peculiar to itself and not to be confused with any other creature’s milkfat. This species-to-species variation in the flavor palette of milkfat is the strongest marker by which newborns instinctively recognize the milk of their own kind.
Divert milk into the outside world, and all the intricacies of milkfat have a new theater in which to operate. It’s a subject to defeat even textbooks of dairy chemistry, which always acknowledge that much remains to be discovered about such-and-such aspects of milkfat. The only aspects I will touch on, as the ones most related to flavor, are globule membranes, fatty-acid content, and true buttermilk.
Milkfat exists in milk as tiny globules surrounded by delicate but surprisingly strong membranes whose composition is still not fully understood because even trying to study them under a microscope distorts their structure. To an extent, the membranes protect the globule contents—a soup of different fatty acids, together with other fat-related substances too complicated to discuss here—against attack by outside forces.
You can think of the membranes as something like the film around soap bubbles, except that they have a much more complex architecture, with microscopically thin outer and inner layers comprising intricate mixtures of fat-related substances and numerous enzymes. If you have tried the mini-experiment in buttermaking at the start of this book, or whipped some cream by the directions on this page, you have explored one way to knock apart the many substances making up the globule membrane—releasing flavors that would not register as clearly otherwise—while also letting the enclosed fat flow out of the former “bubble.”
There are other conditions under which the membrane can be breached and the contents spilled out, but usually with nastier or at least trickier results. Handle milk, cream, or butter without an eye to sanitation, and eventually you will invite certain bacteria or enzymes that dismantle fat globules, releasing the hideously penetrating flavors of rancidity. “Lipolysis,” or breakdown of fat, is the technical name. But curiously enough, small amounts of controlled lipolytic action are exactly what’s needed to produce the bracing sting of several excellent Italian cheeses—just one instance of the truth that harnessing the flavor potential of milkfat takes exceeding skill and experience.
The next culinary dimension of milkfat that cooks need to know something about is what kinds of fatty acids it contains. Here I must gloss over many niceties of technical definition to explain that any edible fat in our kitchens, from peanut oil to rendered lard, basically consists of compounds properly called “triglycerides.” The last three syllables reflect the fact that they all involve a molecule of an alcohol known as “glycerol,” which is reponsible for the basic effect of suave fattiness in fats. The “tri” part means that they all contain three fatty-acid molecules tacked on to the glycerol like three pennants waving from a pole. The truly dizzying aspects of the picture are first, that fatty acids come in phenomenal numbers of different configurations; second, that any triglyceride molecule can contain a mix-and-match assortment of any three fatty acids from the whole spectrum; and third, that all the resulting permutations and combinations will taste different.
Most of the vegetable oils used in cooking contain at least dozens of individual fatty acids. But by comparison, the fat in cows’ milk is now known to have more than four hundred, shuffled like cards in a deck to furnish the different “tri’s” in thousands of triglycerides. Undoubtedly, milkfat from other animals is equally complex. But the unique commercial importance of cows’ milk means that it’s been better studied than any of the others.
There are several ways to distinguish different kinds of fatty acids. Most are beyond the scope of a book like this. Those important enough for cooks and consumers to warrant brief explanations start with volatility, or the tendency to evaporate at fairly low temperatures. Heat a bit of butter barely above lukewarm and, as you have just seen, the more volatile fatty acids will vanish in a puff of fragrance, never to be recovered.
Individual members of the fatty-acid tribe are also often grouped under the rubrics “short chain,” “medium chain,” and “long chain,” referring to the actual length of the molecule as measured by counting basic architectural units. These units consist of carbon atoms—in most cases from four to twenty-two—linked with one another in arrangements that can be very crudely visualized as daisy chains with many odd twists and turns in three-dimensional space. Every carbon atom on the chain has hydrogen atoms attached, but here a whole cluster of variables occurs. Each carbon atom could potentially link up with two hydrogen atoms via straightforward connections called “single bonds.” When every one actually is so linked, the fatty acid is said to be “saturated,” meaning that all potential vacancies for hydrogen are filled. If, however, some are linked with only one hydrogen atom apiece by more tricky and unstable connections (“double bonds”), there are unfilled vacancies and the molecule is said to be “unsaturated.”
For about half a century Americans have been absorbing news bulletins about the qualities of saturated and unsaturated fatty acids; at times it seems as if more pieces of nomenclature are being added every other week. Gradually the experts began explaining that there are kinds and degrees of saturation, and the names of different classifications—sometimes of different individual acids—started showing up in media coverage of health issues. What generally seems to have got lost in the fog of nutribabble is the culinary picture.
Different fats, as we encounter them in the kitchen, contain different balances of saturated and unsaturated fatty acids. Broadly speaking, the ones more weighted toward unsaturation are liquid at room temperature and are called “oils,” while the more saturated fats are solid at the same temperature. But what’s unique about butter is that because of the huge number of different saturated and unsaturated fatty acids stuck onto triglyceride molecules in different combinations, it undergoes a uniquely subtle transition between solid and liquid.
You must also take into account that acids of different chain lengths all have their particular flavors. The shorter ones, which also happen to be somewhat volatile, include the pungent butyric acid and the trio of capric-caproic-caprylic acids that in large amounts produces “goaty-sheepy” effects. The longer ones are usually milder-tasting. Imagine the four hundred–plus chemically distinct fatty acids in cows’-milk butter, all contributing separate jots and tittles of sharpness, roughness, floweriness, waxiness, mellowness, and meltability to what we taste as a single substance.
The butter story involves many other wrinkles that can’t be dealt with here; I have ignored whole categories of compounds that enter into its taste and smell. I will mention only one final factor that sets it apart from all other culinary fats: the strategic impurities of “buttermilk.” If you remember the concept of “phase inversion” (this page), you know that churning milk or cream to butter means agitating an emulsion of fat globules dispersed in a water-based solution, thus breaking up the individual globules enough to let the milkfat inside them separate—more or less—from the rest of the milk and form the continuous mass that we call butter. But butter is never pure butterfat, unless you resort to very drastic industrial separation techniques that produce something lacking the nuances of proper butter. When the formerly dispersed milkfat comes together in a body through churning, it retains minuscule droplets of “buttermilk,” the incompletely separated liquid residue. Even after freshly churned butter is worked and rinsed to remove the buttermilk, faint traces of it remain dispersed through the body of the butter. They contain
enough of the original skim-milk solids to contribute a very faint, elusive milkiness without which butter never quite achieves its full flavor potential.
These same milk solids illustrate just how close the rewards of cooking with dairy products are to the pitfalls. They have the wonderful property of browning, caramelizing, and developing a heavenly flavor when butter is heated to fairly low temperatures, somewhere around 250°F. The white stuff that you saw separating from the clear butterfat in slowly heated butter, then resolving itself into nutty browned particles, was milk solids from retained buttermilk. Unfortunately, their burning point is far below the smoking point of the actual butterfat. Let the temperature increase even slightly, and in a flash the delicious brown flecks will become acridly reeking black flecks, the hallmark of irretrievably burned butter.
Most butter as sold in the United States is only about 80 to 81 percent butterfat. The makeup of the remainder varies according to such factors as whether the butter is salted or unsalted and made from sweet or ripened cream. Most of it is water (either in the retained buttermilk or incorporated in the process of rinsing out the buttermilk) and milk solids. For some purposes such as pastry-making (see the recipe for Pâte Brisée), butterfat content of 82 percent or higher is desirable. In most other kinds of cooking, the nuances contributed by trace amounts of buttermilk are actually a virtue—though too much gives the butter a leaky body and a propensity to go bad.
Milk Page 29