Pork-fat (lard), when used alone, reaches 392° F. without burning. Very pure goose dripping withstands 428° F.; and, finally, vegetable fats may reach, without burning, 482° F. in the case of cocoa-nut butter, 518° F. with ordinary oils, and 554° in the case of olive oil.
The temperature of ordinary frying fat may be tested thus: it is moderately hot when, after throwing a sprig of parsley or a crust of bread into it, it begins to bubble immediately; it is hot if it crackles when a slightly moist object is thrust into it; it is very hot when it gives off a thin white smoke perceptible to the smell.
The first temperature, “moderately hot,” is used (1) for all products containing vegetable water the complete evaporation of which is necessary; (2) for fish whose volume exacts a cooking process by means of penetration, previous to that with concentration.
In the first degree of heat with which it is used the frying fat therefore only effects a kind of preparatory operation.
The second temperature, “hot,” is used for all products which have previously undergone an initial cooking process in the first temperature, either for evaporation or penetration, and its object is either to finish them or to cover them with a crimped coating.
It is also applicable to those products upon which the frying fat must act immediately by concentration—that is to say, by forming a set coating around them which prevents the escape of the contained substances.
Objects treated with this temperature are: all those [panés à l’anglaise] or covered with batter, such as various croquettes, cromesquis, cutlets, and collops à la Villeroy, fritters of all kinds, fried creams, &c.
In this case the frying medium acts by setting, which in certain cases is exceedingly necessary.
1. If the objects in question are [panés à l’anglaise], i.e., [126] ]dipped in beaten eggs and rolled in bread-crumbs, the sudden contact of the hot grease converts this coating of egg and bread-crumbs into a resisting crust, which prevents the escape of the substances and the liquefied sauce contained within.
If these objects were plunged in a fat that was not sufficiently hot, the coating of egg and bread-crumbs would not only imbibe the frying medium, but it would run the risk of breaking, thereby allowing the escape of the very substances it was intended to withhold.