When cheese is used to bring flavor and richness to a sauce 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.