How Some Familiar Cheeses Are Made

Draining, Shaping, and Salting the Curds The curds can be drained of their whey in several ways, depending on how much moisture the cheesemaker wants to remove from the curd. For some soft cheeses, the whole curd is carefully ladled into molds and allowed to drain by force of gravity alone, for many hours. For firmer cheeses, the curd is precut into pieces to provide more surface area from which the whey can drain or be actively pressed. The cut curd of large hard cheeses may also be “cooked” in its whey to 130ºF/55ºC, a temperature that not only expels whey from the curd particles, but also affects bacteria and enzymes, and encourages flavor-producing chemical reactions among some milk components. Once the curd pieces are placed in the mold that gives the cheese its final shape, they may be pressed to squeeze out yet more moisture.

The cheesemaker always adds salt to the new cheese, either by mixing dry salt with the curd pieces or by applying dry salt or brine to whole cheese. The salt provides more than its own taste. It inhibits the growth of spoilage microbes, and it’s an essential regulator of cheese structure and the ripening process. It draws moisture out of the curds, firms the protein structure, slows the growth of ripening microbes, and alters the activity of ripening enzymes. Most cheeses contain between 1.5 and 2% salt by weight; Emmental is the least salty traditional cheese at about 0.7%, while feta, Roquefort, and pecorino may approach 5%.

Ripening, or Affinage Ripening is the stage during which microbes and milk enzymes transform the salty, rubbery, or crumbly curd into a delicious cheese. The French term for ripening, affinage, comes from the Latin finus, meaning “end” or “ultimate point,” and was used in medieval alchemy to describe the refining of impure materials. For at least 200 years it has also meant bringing cheeses to the point at which flavor and texture are at their best. Cheeses have lives: they begin young and bland, they mature into fullness of character, and they eventually decay into harshness and coarseness. The life of a moist cheese like Camembert is meteoric, its prime come and gone in weeks, while the majority of cheeses peak at a few months, and a dry Comté or Parmesan slowly improves for a year or more.

The cheesemaker initiates and manages this maturation process by controlling the temperature and humidity at which the cheese is stored, conditions that determine the moisture content of the cheese, the growth of microbes, the activity of enzymes, and the development of flavor and texture. Specialist cheese merchants in France and elsewhere are also affineurs: they buy cheeses before they have fully matured, and carefully finish the process on their premises, so that they can sell the cheeses at their prime.

Industrial producers usually ripen their cheeses only partly, then refrigerate them to suspend their development before shipping. This practice maximizes the cheeses’ stability and shelf life at the expense of quality.

OPPOSITE: Principal cheese families. Only distinctive processing steps are shown; most cheeses are also salted, shaped in molds, and aged for some time. Curdling the milk, cutting the curd, heating the curd particles, and pressing are methods of removing progressively more moisture from a cheese, slowing its aging, and extending its edible lifetime.

The Sources
of Cheese Diversity

So these are the ingredients that have generated the great diversity of our traditional cheeses: hundreds of plants, from scrubland herbs to alpine flowers; dozens of animal breeds that fed on those plants and transformed them into milk; protein-cutting enzymes from young animals and thistles; microbes recruited from meadow and cave, from the oceans, from animal insides and skins; and the careful observation, ingenuity, and good taste of generations of cheesemakers and cheese lovers. This remarkable heritage underlies even today’s simplified industrial cheeses.

The usual way of organizing the diversity of cheeses into a comprehensible system is to group them by their moisture content and the microbes that ripen them. The more moisture removed from the curd, the harder the cheese’s eventual texture, and the longer its lifespan. A fresh cheese with 80% water lasts a few days, while a soft cheese (45–55%) reaches its prime in a few weeks, a semihard cheese (40–45%) in a few months, a hard cheese (30–40%) after a year or more. And ripening microbes create distinctive flavors. The box on p. 60 shows how cheesemakers create such different cheeses from the same basic materials.

Choosing, Storing,
and Serving Cheese

It has always been a challenge to choose a good cheese, as Charlemagne’s instructor admitted (p. 53). A late medieval compendium of maxims and recipes for the middle-class household, known as Le Ménagier de Paris, includes this formula “To recognize good cheese”:

Not at all white like Helen,

Nor weeping, like Magdalene.

Not Argus, but completely blind,

And heavy, like a buffalo.

Let it rebel against the thumb,

And have an old moth-eaten coat.

Without eyes, without tears, not at all white,

Moth-eaten, rebellious, of good weight.

But these rules wouldn’t work for young goat cheeses (white and coatless), Roquefort (with its pockets of whey), Emmental (eyefull and light), or Camembert (which should give when thumbed). As always, the proof is in the tasting.

These days, the most important thing is to understand that bulk supermarket cheeses are only pale (or dyed) imitations of their more flavorful, distinctive originals. The way to find good cheeses is to buy from a specialist who loves and knows them, chooses the best and takes good care of them, and offers samples for tasting.

Cut to Order Whenever possible, buy portions that are cut while you watch. Precut portions may be days or weeks old, and their large exposed surfaces inevitably develop rancid flavors from contact with air and plastic wrap. Exposure to light in the dairy case also damages lipids and causes off-flavors in as little as two days; in addition it bleaches the annatto in orange-dyed cheeses, turning it pink. Pregrated cheese has a tremendous surface area, and while it is often carefully wrapped, it loses much of its aroma and its carbon dioxide, which also contributes the impression of staleness.

Cool, Not Cold If cheese must be kept for more than a few days, it’s usually easiest to refrigerate it. Unfortunately, the ideal conditions for holding cheese — a humid 55–60ºF/12–15ºC, simply a continuation of its ripening conditions — is warmer than most refrigerators, and cooler and moister than most rooms. Refrigeration essentially puts cheese into suspended animation, so if you want an immature soft cheese to ripen further, you’ll need to keep it warmer.

Cheeses should never be served direct from the refrigerator. At such low temperatures the milk fat is congealed and as hard as refrigerated butter, the protein network unnaturally stiff, the flavor molecules imprisoned, and the cheese will seem rubbery and flavorless. Room temperature is best, unless it’s so warm (above about 80ºF/26ºC) that the milk fat will melt and sweat out of the cheese.

Loose Wrapping Tight wrapping in plastic film is inadvisable for three reasons: trapped moisture and restricted oxygen encourages the growth of bacteria and molds, not always the cheese’s own; strong volatiles such as ammonia that would otherwise diffuse from the cheese instead impregnate it; and trace volatile compounds and plastic chemicals migrate into the cheese. Whole, still-developing cheeses should be stored unwrapped or very loosely wrapped, other cheeses loosely wrapped in wax paper. Stand them on a wire rack or turn them frequently to prevent the bottom from getting soggy. It can be fun to play the role of affineur and encourage surface or blue mold from a good Camembert or Roquefort to grow on a fresh goat cheese or in a piece of standard Cheddar. But there’s some risk that other microbes will join in. If a piece of cheese develops an unusual surface mold or sliminess or an unusual odor, the safest thing is to discard it. Simply trimming the surface will not remove mold filaments, which can penetrate some distance and may carry toxins (p. 67).

Rinds Should cheese rinds be eaten? It depends on the cheese and the eater. The rinds of long-aged cheeses are generally tough and slightly rancid, and are best avoided. With softer cheeses it’s largely a matter of taste. The rind can offer an interesting contrast to the interior in both flavor and texture. But if safety is a concern, then consider the rind a protective coating and trim it off.

Cooking with Cheese

When used as an ingredient in cooking, cheese can add both flavor and texture: either unctuousness or crispness, depending on circumstances. In most cases, we want the cheese to melt and either mix evenly with other ingredients or spread over a surface. A certain giving cohesiveness is part of the pleasure of melted cheese. Stringy cheese can be enjoyable on pizzas, but a nuisance in more formal dishes. To understand cheese cooking, we need to understand the chemistry of melting.

Cheese Melting What is going on when we melt a piece of cheese? Essentially two things. First, at around 90ºF, the milk fat melts, which makes the cheese more supple, and often brings little beads of melted fat to the surface. Then at higher temperatures — around 130ºF/55ºC for soft cheeses, 150ºF/65ºC for Cheddar and Swiss types, 180ºF/82ºC for Parmesan and pecorino — enough of the bonds holding the casein proteins together are broken that the protein matrix collapses, and the piece sags and flows as a thick liquid. Melting behavior is largely determined by water content. Low-moisture hard cheeses require more heat to melt because their protein molecules are more concentrated and so more intimately bonded to each other; and when melted, they flow relatively little. Separate pieces of grated moist mozzarella will melt together, while flecks of Parmesan remain separate. With continued exposure to high heat, moisture will evaporate from the liquefied cheese, which gets progressively stiffer and eventually resolidifies. Most cheeses will leak some melted fat, and extensive breakdown of the protein fabric accentuates this in high-fat cheeses. The ratio of fat to surrounding protein is just 0.7 in part-skim Parmesan, around 1 in mozzarella and the alpine cheeses, but 1.3 in Roquefort and Cheddar, which are especially prone to exuding fat when melted.

Nonmelting Cheeses There are several kinds of cheese that do not melt on heating: they simply get drier and stiffer. These include Indian paneer and Latin queso blanco, Italian ricotta, and most fresh goat cheeses; all of them are curdled exclusively or primarily by means of acid, not rennet. Rennet creates a malleable structure of large casein micelles held together by relatively few calcium atoms and hydrophobic bonds, so this structure is readily weakened by heat. Acid, on the other hand, dissolves the calcium glue that holds the casein proteins together in micelles (p. 20), and it eliminates each protein’s negative electrical charge, which would otherwise cause the proteins to repel each other. The proteins are free to flock together and bond extensively into microscopic clumps. So when an acid curd is heated, the first thing to be shaken loose is not the proteins, but water: the water boils away, and this simply dries out and concentrates the protein even further. This is why firm paneer and queso blanco can be simmered or fried like meat, and goat cheeses and ricotta maintain their shape on pizzas or in pasta stuffings.

Stringiness Melted cheese becomes stringy when mostly intact casein molecules are cross-linked together by calcium into long, rope-like fibers that can stretch but get stuck to each other. If the casein has been attacked extensively by ripening enzymes, then the pieces are too small to form fibers; so well-aged grating cheeses don’t get stringy. The degree of cross-linking also matters: a lot and the casein molecules are so tightly bound to each other that they can’t give with pulling, and simply snap apart; a little and they pull apart right away. The cross-linking is determined by how the cheese was made: high acidity removes calcium from the curd, and high moisture, high fat, and high salt help separate casein molecules from each other. So the stringiest cheeses are moderate in acidity, moisture, salt, and age. The most common stringy cheeses are intentionally fibrous mozzarella, elastic Emmental, and Cheddar. Crumbly cheeses like Cheshire and Leicester, and moist ones like Caerphilly, Colby, and Jack are preferred for making such melted preparations as Welsh rarebit, stewed cheese, and grilled-cheese sandwiches. Similarly, Emmental’s alpine cousin Gruyère is preferred in fondues because it’s moister, fatter, and saltier. And the Italian grating cheeses — Parmesan, grana Padano, the pecorinos — have had their protein fabric sufficiently broken that its pieces readily disperse in sauces, soups, risottos, polenta, and pasta dishes.

Cheeses are at their stringiest right around their melting point — which usually means right about the point that a piping hot dish gets cool enough to eat — and get more so the more they are stirred and stretched. One French country dish, aligot from the Auvergne, calls for unripened Cantal cheese to be sliced, mixed with just-boiled potatoes, and sweepingly stirred until it forms an elastic cord that can stretch for 6 to 10 feet/2–3 meters!

Cheese Sauces and Soups When cheese is used to bring flavor and richness to a sauce (Gruyère or Parmesan in French sauce Mornay, Fontina in Italian fonduta) or a soup, the aim is to integrate the cheese evenly into the liquid. There are several ways to avoid the stringiness, lumps, and fat separation that result when the cheese proteins are allowed to coagulate.

• Avoid using a cheese that is prone to stringiness in the first place. Moist or well-aged grating cheeses blend better.
• Grate the cheese finely so that you can disperse it evenly throughout the dish from the beginning.
• Heat the dish as little as possible after the cheese has been added. Simmer the other ingredients together first, let the pot cool a bit, and then add the cheese. Remember that temperatures above the cheese’s melting point will tend to tighten the protein patches into hard clumps and squeeze out their fat. On the other hand, don’t let the dish cool down too much before serving. Cheese gets stringier and tougher as it cools down and congeals.
• Minimize stirring, which can push the dispersed patches of cheese protein back together into a big sticky mass.
• Include starchy ingredients that will coat the protein patches and fat pockets and keep them apart. These stabilizing ingredients include flour, cornstarch, and arrowroot.
• If the flavor of the dish permits, include some wine or lemon juice — a preventive or emergency measure well known to fans of the ultimate cheese sauce, fondue.

Cheese Fondue In the Swiss Alps, where for centuries cheese has been melted in a communal pot at the table and kept hot over a flame for dipping bread, it’s well known that wine can help keep melted cheese from getting stringy or seizing up. The ingredients in a classic fondue, in fact, are just alpine cheese — usually Gruyère — a tart white wine, some kirsch, and sometimes (for added insurance) starch. The combination of cheese and wine is delicious but also savvy. The wine contributes two essential ingredients for a smooth sauce: water, which keeps the casein proteins moist and dilute, and tartaric acid, which pulls the cross-linking calcium off of the casein proteins and binds tightly to it, leaving them glueless and happily separate. (Alcohol has nothing to do with fondue stability.) The citric acid in lemon juice will do the same thing. If it’s not too far gone, you can sometimes rescue a tightening cheese sauce with a squeeze of lemon juice or a splash of white wine.

Toppings, Gratins When a thin layer of cheese is heated in the oven or under a broiler — on a gratin, a pizza, or bruschetta — the intense heat can quickly dehydrate the casein fabric, toughen it, and cause its fat to separate. To avoid this, watch the dish carefully and remove it as soon as the cheese melts. On the other hand, browned, crisp cheese is quite delicious: the religieuse at the bottom of the fondue pot crowns the meal. If you want a cheese topping to brown, then pick a robust cheese that resists fat loss and stringiness. The grating cheeses are especially versatile; Parmesan can be formed into a thin disk and melted and lightly browned in a frying pan or the oven, then molded into cups or other shapes.

Process and Low-Fat Cheeses

Process cheese is an industrial version of cheese that makes use of surplus, scrap, and unripened materials. It began as a kind of resolidified, long-keeping fondue made from trimmings of genuine cheeses that were unsaleable due to partial defects or damage. The first industrial attempts to melt together a blend of shredded cheeses were made at the end of the 19th century. The key insight — the necessity of “melting salts” analogous to the tartaric acid and citric acid in a fondue’s wine or lemon juice — came in Switzerland in 1912. Five years later, the American company Kraft patented a combination of citric acid and phosphates, and a decade after that it brought out the popular cheddar look-alike Velveeta.

Today, manufacturers use a mixture of sodium citrate, sodium phosphates, and sodium polyphosphates, and a blend of new, partly ripened, and fully ripened cheeses. The polyphosphates (negatively charged chains of phosphorus and oxygen atoms that attract a cloud of water molecules) not only remove calcium from the casein matrix, but also bind to the casein themselves, bringing moisture with them and thus further loosening the protein matrix. The same salts that melt the component cheeses into a homogeneous mass also help the resulting blended cheese melt nicely when cooked. This characteristic, together with its low cost, has made process cheese a popular ingredient in fast-food sandwiches.

Low- and no-fat “cheese products” replace fat with various carbohydrates or proteins. When heated, such products don’t melt; they soften and then dry out.

Cheese and Health

Cheese and the Heart As a food that is essentially a concentrated version of milk, cheese shares many of milk’s nutritional advantages and disadvantages. It’s a rich source of protein, calcium, and energy. Its abundant fat is highly saturated and therefore tends to raise blood cholesterol levels. However, France and Greece lead the world in per capita cheese consumption, at better than 2 oz/60 gm per day, about double the U.S. figures, yet they’re remarkable among Western countries for their relatively low rates of heart disease, probably thanks to their high consumption of heart-protective vegetables, fruits, and wine (p. 253). Eating cheese as part of a balanced diet is fully compatible with good health.

Food Poisoning

Cheeses Made from Raw and Pasteurized Milks Government concerns about the danger of the various pathogens that can grow in milk led to the U.S. requirement (originating in 1944, reaffirmed in 1949, and extended to imports in 1951) that all cheeses aged less than 60 days be made with pasteurized milk. Since 1948 there have been only a handful of outbreaks of food poisoning in the United States caused by cheese, nearly all involving contamination of the milk or cheese after pasteurization. In Europe, where young raw-milk cheeses are still legal in some countries, most outbreaks have also been caused by pasteurized cheeses. Cheeses in general present a relatively low risk of food poisoning. Because any soft cheese contains enough moisture to permit the survival of various human pathogens, both pasteurized and unpasteurized versions are probably best avoided by people who may be especially vulnerable to infection (pregnant women, the elderly and chronically ill). Hard cheeses are inhospitable to disease microbes and very seldom cause food poisoning.

Storage Molds In addition to the usual disease microbes, the molds that can grow on cheese are of some concern. When cheeses are held in storage for some time, toxin-producing foreign molds (Aspergillus versicolor, Penicillium viridicatum and P. cyclopium) may occasionally develop on their rinds and contaminate them to the depth of up to an inch/2 cm. This problem appears to be very rare, but does make it advisable to discard cheeses overgrown with unusual mold.

Amines There is one normal microbial product that can cause discomfort to some people. In a strongly ripened cheese, the casein proteins are broken down to amino acids, and the amino acids can be broken down into amines, small molecules that can serve as chemical signals in the human body. Histamine and tyramine are found in large quantities in Cheddar, blue, Swiss, and Dutch-style cheeses, and can cause a rise in blood pressure, headaches, and rashes in people who are especially sensitive to them.

Tooth Decay Finally, it has been recognized for decades that eating cheese slows tooth decay, which is caused by acid secretion from relatives of a yogurt bacterium (especially Streptococcus mutans) that adhere to the teeth. Just why is still not entirely clear, but it appears that eaten at the end of a meal, when streptococcal acid production is on the rise, calcium and phosphate from the cheese diffuse into the bacterial colonies and blunt the acid rise.