Rendering
Rendering is the process of melting fat out of fatty tissue, such as bacon, duck skin, or pork trimmings, by cooking it slowly over gentle heat. The liquid fat is either used right away for cooking or strained and saved, leaving behind crispy skin or crunchy cracklings.
How it works
Animal fat isn't just a solid lump. It's stored in fat cells held together by connective tissue and water. Gentle heat does three jobs at once:
- Melts the fat. Pork and chicken fat soften at fairly low temperatures; beef fat is firmer and needs a bit more heat.
- Breaks down connective tissue, which frees fat trapped in the cells.
- Evaporates water. That's the steady bubbling you hear. When the bubbling quiets, most of the moisture is gone.
Too much heat at the start browns and toughens the outside before the fat inside has a chance to escape. That's why rendering is done low and slow.
Rendering while you cook
Bacon. Lay strips in a cold pan, then heat over medium-low. The fat melts out first and the bacon fries in it, giving flatter, more evenly crisp strips.
Duck breast. Score the skin in a crosshatch without cutting the meat. Start skin-side down in a cold, dry pan over medium-low and cook 10–15 minutes, pouring off fat as it collects. The skin turns thin and crackly, then you flip briefly to finish. Duck breast is safe at 74 °C (165 °F) per USDA, though many cooks serve it pinker.
Chicken thighs and pork belly. Skin-side down over moderate heat until the skin releases on its own and is deeply golden.
Chef Fizz says: Don't toss the fat in the pan. Potatoes roasted in duck fat are basically a reward for patience.
Rendering fat to store
- Chop or grind cold fat (pork back fat, beef suet, chicken skin) into small pieces.
- Add a splash of water, about 60 ml (¼ cup) per kilogram (2.2 lb), to help it start melting without scorching.
- Cook on low heat, stirring occasionally, 1–3 hours depending on the amount.
- When the bubbling slows and the bits are golden, strain through a fine sieve or cheesecloth.
- Cool, then refrigerate in a clean jar.
Pure white leaf lard, from the fat around pork kidneys, is prized for pastry. Tallow makes outstanding fries. Schmaltz is a classic in Jewish cooking for matzo balls and chopped liver, with the crisp bits (gribenes) as a snack.
Common mistakes
- Starting too hot. The outside burns and the fat tastes scorched.
- Not straining well. Leftover meat bits and water make stored fat spoil faster.
- Pouring hot fat down the drain. It solidifies in pipes. Cool it and bin it, or save it for cooking.
- Rushing duck skin. Thick, chewy skin almost always means it needed more time on lower heat.
Questions
Why start bacon or duck breast in a cold pan?
A cold start lets the fat melt out gradually before the meat and skin overcook. By the time the pan is hot, most fat has rendered and the skin or bacon can crisp evenly.
How do you know when fat is fully rendered?
The bubbling slows and quiets because the water has cooked off, the liquid fat turns clear, and any remaining bits are golden and crisp. These bits are called cracklings.
How long does rendered fat keep?
Strained, rendered fat keeps for about 3 months in a sealed jar in the fridge and up to a year in the freezer. Straining out all solids and water helps it last.
What is the difference between lard, tallow, and schmaltz?
Lard is rendered pork fat, tallow is rendered beef or lamb fat, and schmaltz is rendered chicken or goose fat. They have different flavours and firmness at room temperature.