Actually, oil and shortening are one and the same, but the shortening has been hydrogenated to some extent to give it the characteristic “plastic” consistency. The shortening completely melts during the baking of the crust and is absorbed into the dough so there really isn’t any difference in texture of baked crusts made with shortening or oil. The exception to this might be in a situation where a highly hydrogenated shortening (has a very hard consistency) is used at high levels (6% and above). In a case like this you might be able to detect a slight waxy mouthfeel with the crust containing the shortening.
If we are talking about oil or shortening in the pan (deep-dish pizza) that is a whole different story. Now we have a situation where the shortening is absorbed only into the outer 1/8-inch or so of the crust during baking and as the pizza is eaten you might detect a slightly waxy mouth feel to the crust. This can be avoided by using a low melting point shortening (think margarine). Table grade margaring is designed to melt at mouth temperature so you don’t experience the waxy mouth feel. Butter would work in exactly the same way. When you use oiol in the pan you don’t experience this problem of waxy mouth feel since the oil is always fluid, but it brings it’s own baggage to the table. When eating a pan pizza made with oil in the pan everything feels oily when you’re eating the pizza.
And lastly, oils come in a lot more “flavors” than shortenings do. Most shortenings are made from deodorized vegetable oils (corn, soy, canola, cottonseed, sunflower and a few more. Oils are made from the same sources but may also include olive (we all know the flavor of this one), and sesame (for that oriental flavor). Why do the majority of pizza makers use oil today? Convenience (you can pour it rather than having to scoop it) and flavor (I’m not aware of any shortening made from olive oil so the olive oil is used for the flavor it imparts. Sometimes, as a cost savings the olive oil is blended with a vegetable oil. This results in an oil with the flavor of olive oil but at a significantly lower cost.
Tom Lehmann/The Dough Doctor