How do I make stock from leftovers?

Stock is what turns scraps into the foundation of most cooking. It costs nothing beyond time, it freezes indefinitely, and homemade stock is noticeably better than any cube in soups, risottos and sauces.

What you'll need

• Large pot
• Freezer bag
• Sieve (optional)
• Containers or ice cube trays (optional)

Step by step

1. Keep a bag in the freezer for stock ingredients.Onion skins, carrot tops, celery ends, herb stalks, chicken carcasses, parmesan rinds. When the bag is full, make stock.
2. Roast bones first for a deeper flavour.Twenty to thirty minutes at 200°C until well browned. It makes the difference between a pale stock and a rich one.
3. Cover with cold water and bring slowly to a simmer.Cold water starting slowly extracts more. Just enough water to cover — more water makes weaker stock.
4. Never let it boil.A bare simmer with the occasional bubble. Boiling emulsifies the fat and makes the stock cloudy and greasy, which cannot be reversed.
5. Skim the scum in the first twenty minutes.Grey foam rises early. Skimming it gives a cleaner-tasting, clearer stock.
6. Simmer for the right length of time.Vegetable stock about an hour, chicken three to four, beef bones six or more. Over-simmering vegetables makes stock bitter.
7. Do not salt it.You will reduce it or use it in seasoned dishes. Salted stock reduced later becomes far too salty. Season the finished dish instead.
8. Strain, cool quickly and freeze in useful portions.Ice cube trays for small amounts, larger containers for soup. It keeps for months and takes up little space if reduced first.

Tips

• Avoid brassicas — cabbage, broccoli, sprouts — in stock. They turn it sulphurous and bitter.
• Reducing the finished stock hard concentrates it into a small volume that takes up almost no freezer space. Dilute it when using.
• Chill the stock and lift the solidified fat off the top. The fat is excellent for roasting potatoes.

Common mistakes

• Boiling the stock — It emulsifies the fat into the liquid, giving permanently cloudy, greasy stock. A bare simmer is the whole technique.
• Salting the stock — It is a base ingredient that will often be reduced. Salted stock reduced later becomes inedibly salty.
• Adding too much water — Stock strength is determined by the ratio of ingredients to water. Just covering is right; filling the pot gives weak stock.

Questions people ask