Beef: a buyer's guide

After an animal dies, enzymes are freed from the control systems that keep them in check during life and they start to indiscriminately attack the cell molecules around them. Fortunately for the eater of its meat this violent rampage boosts flavour and increases tenderness.

Larger low-flavour molecules are broken down into smaller, flavourful fragments, fibres are loosened and connective tissue starts to break down. All this helps to turn the mild flavour and springy texture of fresh meat, which may look beefy, but is often watery and insipid, into tender mouthfuls of intensely flavoured aged beef. The extent to which this process takes place depends on what happens to the meat after the animal is slaughtered.

Our Longhorns are split into two "sides", each of which is then hung in a cold room for 21 days. These sides are then cut into sections (eg a run of ribs or a whole rump) that are left for another 14 days. We've found that the rump improves after a further twenty days, so, whilst most of our steaks come from meat that has been "dry-aged" (as this process is known) for 35 days, our rumps get 55.

Walk into the ageing room at the farm and you will be confronted by a wall of meat and a pleasant musty smell with a touch of blue cheese to it. The process of dry ageing promotes the growth of certain moulds on the external surface of the meat that produce their own enzymes, further helping to tenderise and boost flavour. By the time it's ready to eat, the beef will often have a thick bloom of mould, all of which needs to be lopped off before the sections are cut into steaks and cooked. The meat we use doesn't get vac-packed: in fact, it never comes into contact with plastic at all.

At the other end of the spectrum, industrial beef producers like to do things a little quicker. They might run an electric current through a fresh carcass for up to 30 minutes, as they've found that this can help tenderise the meat, before breaking it down into steaks and other cuts in a process known as "hot boning" because the animal's body is still warm. Most of this meat will end up on supermarket shelves within a few days, but some might sit in their vac-packs for a while, a period known to some as "wet-ageing".

When meat is dry-aged two beneficial factors are at play: those rampaging enzymes and water loss through evaporation (fresh beef is about 70% water). After 35 days our beef will have lost about 20% of its weight and, as this lost weight is flavourless water, the flavour of the remaining meat is intensified. Added to this, any surfaces exposed to the air during dry-ageing need to be trimmed, resulting in even more weight loss. Mass beef producers don't like this as it means they have less meat to sell, so in the 1970s they found a solution: wet-ageing, which results in zero weight-loss (unless you count the bloody, but flavoursome juice you have to pour down the sink when you open the vac-pack).

For the eater, though, this beef misses out on that all-important intensification of flavour, it can also lead to slightly sour and metallic flavours in the meat due to increased acidity, and it prevents some of those enzymes from doing their cell-busting work, resulting in less flavourful meat. Another counter-intuitive result is that dry-aged beef with its lower water content also ends up seeming juicier than wet-aged beef.