Doughnuts were of course known as “oily cakes” among the Dutch back in the day. And believe it or not, that was meant as a term of endearment. As happy as the Dutch were to fry in oil at one time, however, it’s believed that well before they ever brought their proto-doughnuts to our shores, the frying medium of choice had changed from oil to pig fat. This only makes sense, since liquid oils have to be pressed from seeds (really the germs of seeds) of various types, a rather laborious and expensive process back then. And pigs, well, there’s a post called Pigs in America that will give you the lowdown on those.
Oh ho! Pig fat! you say. But then what else could one expect from a people as woefully ignorant of food and nutrition as our ancestors? Yeah well, Mr. Frontal Lobe, it turns out there was more than a little method in that madness. Pig fat is a solid fat, at least when it’s at room temperature. Apply heat to it and it melts, becoming an extremely flavorful frying medium (yes, even for sweets). Let it cool and it firms back up again. The advantage: no oily-textured “oily cakes”.
We moderns employ the exact same principle in our doughnuts, only we do it with artificially solidified vegetable fats. Check the back of your average doughnut shop and you’ll find a stack of boxes full of hydrogenated shortening. This stuff started out as oil, but was converted into solid form by virtue of a few hydrogen atoms and a catalyst. Just like pig fat, its primary advantage is that it creates doughnuts that are far less “greasy” in appearance compared those fried in oil.
There are several other technical advantages to a solid fat as a frying medium, but more on that soon.