Quote Originally Posted by JDM61 View Post
Lard, duck fat, butter, etc are all muy bueno, but they do have a flavor of their own. Plain Crisco really does not and, IMO, it does certain things better than say a comparable neutral veggie oil. I use it to fry but also to season cast iron pans. It seems to work much better than oil for me. With that said, something like biscuit can handle a more flavorful fat.
True, the fat can provide flavors but it also can affect structure. For example, if you take the same cookie recipe and use butter vs. crisco, the butter cookie will spread thin in the oven and the final cookie will be crispy. A crisco cookie will puff up and go more toward chewy. This is a result of melting temp. Butter melts faster so the cookie dough will spread before the baking powder can puff up the cookie. The crisco melts slower at a higher temp so the cookie can puff before spreading. The difference in melting temps can affect rise in a biscuit too. I don't have data to cite, but from experience I know a fat change will make changes to the final result.