High on the hog: Pressure-rendered lard
For the best flavour in my flour tortillas, I wanted lard that was not the highly processed, shelf-stable stuff you can find in bricks at the grocery store. I wanted real lard, rendered pork fat, something with flavour. (It seems like nearly every animal fat gets a special name once it’s been rendered: lard for pork, tallow for beef, schmaltz for chicken. Duck fat gets the short end of the stick in the nomenclature department, but then, duck fat is its own reward.)
I’m sure real lard can be bought, but given that I already had some pork back fat on hand, it seemed easier to render it myself than to find a source. Modernist Cuisine outlines a few ways to render fat: directly over heat; with water; sous vide; and by pressure-rendering. Naturally, given how much of a pressure-cooker convert I am, I had to try the pressure-rendering method.
The basics are: put the raw fat, 0.4% of its weight in baking soda, and water to cover into a canning jar, put the lid on the jar, place in a pressure cooker with water in the bottom, and cook at high pressure for 4 hours. In general, the smaller the pieces of fat, the faster it renders, so I ran the fat through my meat grinder. (Some people even put the fat and water in their blender, making a kind of paste from it, which separates when the fat melts.)
I loved the sound of this approach from a “set it and forget it” perspective: normally when rendering fat, you need to keep an eye on it to make sure it doesn’t get too hot. While high heat makes for delicious cracklings, it also degrades the fat, making it more prone to rancidity and lowering its smoke point. In the pressure cooker, this wasn’t a worry, so once I found the magic spot on the dial where the pressure would stay constant for four hours, I could just walk away and let it cook.
The baking soda in the Modernist Cuisine approach is intended to improve the flavour and clarity of the fat. Certainly the final product was the whitest fat I’ve ever rendered, and the flavour was very lard-like, but never having rendered fat in a pressure cooker without baking soda, I don’t really have anything to compare it to.
The only drawback to this approach is the size limitation: there’s space for only so many jars in my pressure cooker, and space for only so much fat in each jar. Plus, it may take somewhat less time than open-pan rendering, but it’s still not exactly “fast.” So I wouldn’t want to try pressure-rendering enough fat for, say, deep-frying. But to get a good, high-quality fat for making tortillas, it worked beautifully.