THE WAY TO TEST HOT FAT.
If a bit of dry bread will brown in one minute fat is hot enough for a raw mixture. If cooked mixtures are to be browned the fat should be hot enough to brown a piece of bread in forty seconds. This method however, is only a makeshift and is not absolutely accurate. A thermometer should be used; 380 to 390 degrees is the right temperature for frying vegetable substances. Heat fat slowly.