thicken the sauce If heated excessively, the chains aggregate and coagulate in compact clumps (right) that give the sauce a curdled consistency and appearance Careful Temperature Control Cooks first make the flavorful but thin liquid that will be the bulk of the sauce and then add a source of finely suspended proteins An example is the fricassee, in which the liquid is the stock in which chicken or another meat has been cooked, and the protein source is egg yolks The mixture is then heated gently At the point that the proteins unfold and begin to tangle — but before they form strong bonds — the sauce thickens noticeably: it clings to a spoon rather than running off The attentive cook immediately takes the sauce from the heat and stirs, thus preventing the proteins from forming very many strong bonds, until the sauce cools enough to prevent further bonding If the sauce gets too hot and the proteins do form strong bonds, they clot together into dense particles, and the sauce becomes grainy and thins out again Most animal proteins coagulate beginning around 140ºF/60ºC, but this critical point can vary, so there’s no substitute for careful monitoring of the sauce’s consistency Once the sauce has thickened, careful straining can remove the few particles that may have formed In all protein-thickened sauces, the cook must take care when mixing the hot sauce with the cool thickener It’s always safest to stir some of the sauce into the thickener, thus heating the thickener gently and diluting it, and then add that mixture to the rest of the sauce If the thickener goes directly into the sauce, then some of the thickener will get instantly overheated and coagulate into grainy particles Cooks sometimes work pastes of liver or shellfish organs into butter and then chill the mix When a chunk of the mix is added to the sauce, the butter melts and slowly releases the thickener into the sauce, ... must take care when mixing the hot sauce with the cool thickener It’s always safest to stir some of the sauce into the thickener, thus heating the thickener gently and diluting it, and then add that mixture to the rest of the. .. liver or shellfish organs into butter and then chill the mix When a chunk of the mix is added to the sauce, the butter melts and slowly releases the thickener into the sauce, ... and then add that mixture to the rest of the sauce If the thickener goes directly into the sauce, then some of the thickener will get instantly overheated and coagulate into grainy particles Cooks sometimes work pastes of liver or shellfish organs into butter and then