The fat aisle wants four pounds a jar for what the butcher throws away. Rendering is the oldest trick in the kitchen: low heat, patience, and a bag of trim becomes months of cooking fat. Pick what you are starting with, type the weight, and get the yield, the method, and how long it keeps.
The Rendering Calculator
Pick the raw fat, type the weight: the yield, the method, and how long the jar keeps.
Dry render: no water, low heat, no hurry. If the pieces start frying, the oven is too hot.
Dry rendering, and why this method
This is the dry render: no water, just fat and low heat. It gives a cleaner, harder fat with a longer shelf life and a proper beefy note that suits roasting and frying. Keep the heat low and slow; the moment the pieces fry rather than melt, the fat takes on colour and flavour you did not ask for. The bits left in the sieve are the scratchings, and they are the cook’s wage. Salt them while they are hot.
What to ask the butcher for
Suet is the hard fat from around the kidneys and it renders into the cleanest tallow you can make. Ordinary trim works nearly as well and often costs nothing at all. On the pork side, leaf fat makes the pale, odourless lard the old bakers prized, and back fat makes the everyday jar. Ask at the counter; most butchers are pleased someone still wants it.
Put the jar to work
A spoonful under the joint is where it starts: the roast calculator builds the schedule. The recipes that made these fats famous, and the case for cooking in them again, are the books: Bring Back the Dripping for the British kitchen, Bring Back the Tallow for the American one. And if you are wondering whether a fat belongs on your plate at all, Can I Eat It? has the verdict.
