As it turns out, shortening is a much broader term than most people realize—it’s really just a catch-all word used to describe any type of fat that is solid at room temperature. But we’re so accustomed to thinking of it as a quaint name for Crisco (i.e., the mass-produced vegetable shortening) that it might as well just be the functioning definition. Setting technicality aside, when you see shortening in a recipe, vegetable shortening is usually what is being called for. What sets this ingredient apart (regardless of the brand) is that it is 100 percent fat, which means that it’s very good at its job. And what job is that exactly? Time for a quick science lesson.
Shortening gets its name from the effect it has on dough. According to our friends at Bob’s Red Mill, the fat inhibits gluten from forming big gas bubbles that result in a puffy and glutinous baked good, thereby ‘shortening’ the finished product. In other words, the stuff is responsible for flaky pie crusts and crispy cookies. On the flip side, you’d be hard-pressed to find shortening on the ingredient list of a pizza dough recipe, for example, since this is considered a ‘long’ dough that can stretch and roll. The takeaway? Any fat that’s solid at room temperature can do the job—but vegetable shortening takes the cake (pun intended) since it’s all fat.
One more thing to know about vegetable shortening: It has a bad rep among nutritionists. That’s because it originally contained trans fats, the by-product of the hydrogenation process required to morph vegetable oils into a solid-at-room-temperature product. And consuming a lot of trans fats increases your risk of developing heart disease and stroke, says the American Heart Association. These days, many companies have reformulated their products to remove trans fats from shortening, but it’s still a highly processed ingredient that many health experts caution against.