Cooking a cow, month by month - Ageing beef

Learn how to spot quality tender aged beef

The necessary wastage of outer portions of the carcass makes selling aged meat a costly business. Supermarkets prefer to sell it fresh, ie five to seven days old.

The problem with fresh meat is that it has no flavour, especially the expensive, easycook cuts. Meat acquires tenderness as it ages, and enzymes (proteases) break down the collagen and muscle fibres – a process called proteolysis.

Hanging on the bone is the most popular ageing method, but it’s important to choose an animal that has a decent covering of fat or it will become too dry, losing 15 per cent of its body weight in moisture. With ‘wet ageing’, meat is deboned to form ‘primal cuts’ that are aged in vacuum-sealed packs.

This takes less time and is cheaper, but it’s less effective: if you prevent moisture loss, the flavour is less concentrated. Well, a 28-day-aged rib roast is a wonderful thing, its taste rich and mellow, its texture meltingly tender. 35 days is the tipping point. Beyond that, you need a leadlined stomach.

HOW TO COOK IT Using a sharp knife, clean the heart by trimming off any nerves or fat. Cut it into one-inch cubes and set aside. Combine three diced chillis, four finely chopped garlic cloves, a heaped tablespoon of cumin, a tea-spoon of oregano, a glug of olive oil and 200ml of red-wine vinegar in a bowl.

Mix, pour over the heart and marinate for at least 12 hours in the fridge. Thread the meat on to pre-soaked wooden skewers, and then stick them under a hot grill (or onto a barbecue) for about four minutes each side.Serve with flatbread wraps. Alan Rutter

Buy your meat at Boucherie Michel, First Floor, Jiezuo Building, Xingfucun Zhong Lu, Chaoyang district (6417 0489). Open 9am-8.30pm daily.

Buy your chillis, garlic, cumin, cloves, olive oil and redwine vinegar at Jenny Lou’s, 6 Sanlitun Beixiaojie, Chaoyang district (6461 6928). Open 8am-10pm daily.