Cooking with cheese

Melting cheese

At around 90°F, the milk fat melts, cheese becomes more supple, and fat beads on the surface. At higher temperatures, around 130°F/55°F for soft cheeses, 150°F/65°C for Cheddar and Swiss types, 180°F/82°C for Parmesan and pecorino, bonds holding the casein proteins together begin to break and the protein matrix collapses. Melted cheese flows as thick liquid. The moisture content dictates the melting behavior of cheese. Low moisture cheeses are more concentrated and intimately bonded, therefore, they require more enegry to melt. After continued heat, moisture evaporates and melted cheese resolidifies.

There are several cheeses that do not melt. They just get stiffer and drier. Examples include Indian paneer, Latin queso blanco, Italian ricotta, and most fresh goat cheeses. All of them are curdled primarily by acid, not rennet. Acid dissolves the calcium glue that hold casein proteins together in micelles along with the negative electrical charge. The proteins bond extensively, so when heated, water is lost first before the protein bonds break. As water boils away, the proteins become even more concentrated. Firm paneer and queso blanco can be simmered or fried like meat.

Stringiness

Melted cheese becomes stringy when mostly intact casein molecules are cross-linked together by calcium into long, fibers that can stretch. If, however, casein has been attacked extensively by enzymes, then the pieces are too small to form fibers, as is the case with well aged cheeses. These do not get stringy. The degree of cross linking is such that casein molecules are tightly bound. The molecules just break.

Stringiness, can be determined by how the cheese was made. Stringy cheeses are moderate in acidity, moisture, salt, and age. They are intentionally made fibrous, as is the case with mozzarella, Emmental, and Cheddar. Crumbly cheeses include Cheshire and Leicester. Caefphilly, Colby, and Jack are preferred for melted preparations. Gruyère is the choice for fondues. Italian grating cheeses, such as Parmesan, grana Padano, and pecorinos have a broken protein fabric which makes them ideal to be disperced in dishes.

When preparing cheese sauces and soups, the aim is to integrate the cheese evenly in the liquid to add richness and flavor to the dish. To avoid stringiness, lumps, and fat separation consider the following tips:

• Avoid using cheese prone to stringiness in the first place. Moist or well-aged grating cheeses blend better.
• Grate cheese finely.
• Heat the dish as little as possible after the cheese has been added. Simmer the ingredients first, cool a bit, then add the cheese.
• Minimize stirring as it can push disperesed particles together.
• Include starchy ingredients that coat proteins and fat pockets, keeping them apart. Use stablizing ingredients such as flour, cornstarch, or arrowroot.
• If the flavor permits, use wine or lemon juice.

Cheese fondue

The ingredients for fondue include an alpine cheese such as Gruyère, a tart white wine, some kirsch, and sometimes starch (for added insurance). The wine contributes water, which keeps the casein proteins moist and dilute, and tartaric acid, which pulls off the calcium and leaves casein glueless and separate. Citric acid from a lemon juice does the same thing.

When using cheese as a topping or gratin, keep in mind that too much heat dehydrates the casein fabric, toughens it, and causes the fat to separate. To avoid this, watch the dish carefully when under the broiler or in the oven, and remove as soon as the cheese melts. If you want to brown a cheese topping, pick a robust cheese such as a grating cheese.