Hopefully we’ve all learned that lard won’t kill you, and that it can even be a good choice sometimes. But I have to admit that I’m not totally convinced for health reasons alone–after all, lard is still pure fat. So let’s tackle this from a different perspective and see if lard makes our baked goods more delicious.
Lard and shortening are both 100% fat, while butter is only around 80% fat with 15% water (the rest is proteins and other molecules). The water in butter can act as a sort of glue that holds layers of dough together–think about the sticky paste you can make with just flour and water. But on the other hand, heated water becomes steam, which expands and pushes layers of dough apart in the oven. The trick here seems to be a balance: we want a little bit of water to create steam but not so much that it becomes sticky.
The biggest trick to flaky pastry dough is unevenly distributed fat. The irregular pieces melt during baking and separate layers of dough, which creates a flaky texture rather than a crumbly one. We can only create clumps with a solid fat (you wouldn’t be able to do this with olive oil, for example), so we need a fat that will stay solid at room temperature.[table id=1 /]
You can see that butter is the least forgiving of your choices. If your kitchen gets a little steamy or your hands run warm, the butter will quickly soften too much and melt into the dough. Lard gives you some more breathing room, and one of the biggest benefits of shortening is its higher temperature range. By manipulating the balance of saturated (solid) and unsaturated (liquid) fats in a product like shortening or margarine, food technologists can make a much more forgiving product.
While a higher temperature range means the fat won’t melt in your hands, it also means it doesn’t melt in your mouth. The human mouth should hover around 98° F (as the doctor’s oral thermometer tells you), so butter and lard become deliciously soft as you bite into them. The puff-pastry margarine that can top 100°, on the other hand, makes a finely layered dough but will taste waxy in your mouth because the fat stays solid.
Butter wins. Always.
Leaf lard (what I rendered) and shortening are pretty flavorless on their own. Some other kinds of lard and tallow have a more meaty flavor, which can be really delicious in the right place. But it’s hard to beat the taste of butter.
So what does all of this tell us? For me, it means I can use different fats for different projects. If taste is the most important, I’m sticking to butter. A flaky pie crust might have part butter and part lard for a little less water and a little higher melting point. If I’m going to have to work the dough more, I might go for shortening. Whatever you’re baking, understanding the fat you’re using will help you make it even better.
Science from On Food and Cooking, of course, and Food52.