Why does shortening taste “greasy”?

You know the feeling. You get it when you take a bite of a pie from one of those big chain restaurants. It’s tender, it chews OK, but once you swallow it there’s that lingering film on your tongue and in the inside of your mouth. It’s fat, more specifically vegetable fat (oil), that’s been hydrogenated to create what we know as shortening.

Shortening was originally developed to provide bakers and home cooks with a solid cooking fat that was less expensive than butter. Solid fats are critical the kitchen for a variety of reasons, as any cook who’s ever attempted to maker layer cake with a liquid oil knows. The price of butter can fluctuate wildly, however, and not everybody likes the porky flavor of lard in their peach pie. Hence the excitement that greeted the invention of vegetable shortening 100 years ago.

However while the miracle of hydrogenation was able to harden vegetable oil to the point that it performed in the kitchen like butter, it wasn’t able to precisely mimic it. One of the areas where it fell, er, short, was its melting point. Butter has a melting point of somewhere around 90 degrees Fahrenheit, and begins to soften severely at about 85. Which means when you put it into your 98.6-degree mouth it melts on contact, delivering all its lovely flavor in a few delectable moments before it slips easily down your throat.

Shortening, by contrast, can have a melting point as high as 110 degrees, which is well above body temperature. Put it in your mouth and it will soften, but not melt. The effect is a greasy mouthfeel that lingers after you chew, and must be washed down with some sort of liquid. Some people don’t mind that. I really do, which is why I vastly prefer an all-butter biscuit or an all-butter pie crust (or a doughnut fried in oil). Sometimes I’ll use lard if I can get the good fresh stuff, since it’s very nice too. The tiny can of shortening I keep in my pantry gets used incidentally, when I need a small amount for English muffins or a batch of rolled fondant.