How do I make stock?

Stock is a way of turning things you'd throw away into something better than you can buy. The only real technique is temperature: a bare simmer extracts gelatine and flavour cleanly, while a boil churns fat and proteins into a cloudy emulsion that can't be undone.

What you'll need

• Bones, carcass or vegetable trimmings
• Large pan
• Onion, carrot, celery
• Bay leaf, peppercorns
• Sieve
• Muslin for a clearer result (optional)

Step by step

1. Collect trimmings in the freezer until you have enough.Chicken carcasses, onion skins, carrot ends, celery tops, herb stalks, parmesan rinds. A bag in the freezer costs nothing.
2. For a deeper flavour, roast bones and vegetables first at 200°C until browned.This is the difference between a pale stock and a rich brown one. Worth the extra 40 minutes.
3. Put everything in a pan and cover with cold water.Cold, not hot. Starting cold extracts more cleanly as it heats.
4. Bring slowly to a bare simmer — an occasional bubble, not a boil.This is the whole technique. If it boils, the stock goes cloudy and greasy and you can't reverse it.
5. Skim the foam off the surface for the first 20 minutes.Coagulated proteins. Removing them keeps the stock clear.
6. Simmer for 2–4 hours for chicken, 4–6 for beef bones, 45 minutes for vegetables.Vegetable stock goes bitter if simmered too long — it needs far less time than bone stock.
7. Strain through a fine sieve, ideally lined with muslin.Don't press the solids — pressing forces cloudy particles through.
8. Cool quickly, then refrigerate. Lift the set fat off the top before use.Cooling fast matters for safety. The fat sets into a removable layer, and it's worth keeping for cooking.

Tips

• Freeze stock flat in bags, or in ice cube trays for small amounts. It stacks efficiently and defrosts quickly.
• Avoid brassicas — cabbage, broccoli, sprouts — in stock. They turn it sulphurous.
• A good chicken stock sets to a jelly when cold. That's gelatine from the bones and it's the sign of a well-made stock.
• Don't salt stock. You'll be reducing it or using it in seasoned dishes, and salting early leaves no room to adjust.

Common mistakes

• Letting it boil — It emulsifies fat and proteins into the liquid, producing a permanently cloudy, greasy stock.
• Simmering vegetable stock for hours — Vegetables give up their flavour within an hour and turn bitter beyond that.
• Salting the stock — It concentrates as the stock reduces, leaving you no control over the final dish.
• Pressing the solids when straining — Forces fine particles through and clouds the result.

Questions people ask