Are oysters safe to eat at home, and how do I open one?

Oysters are the one raw animal food most people eat without a second thought, and the risk is not zero. It is also not what folklore says it is: the danger is a virus from the growing water, not a warm month or an oyster that smells fine. Understanding which part is real makes the decision straightforward rather than anxious.

Safety

What you'll need

• A proper oyster knife — short, stubby, blunt-tipped
• A thick folded tea towel or a chainmail glove
• A tray of crushed ice, for serving (optional)

Step by step

1. Buy from somewhere that knows where they came from.UK oysters come from classified harvesting waters and are purified before sale where the classification requires it. A supplier who can tell you the bed and the date is a supplier operating properly. This is the main thing you control.
2. Store them cold, cup-side down, and covered with a damp cloth.Cup down keeps the liquor in, which keeps the oyster alive. In the fridge, never sealed, never in water. They keep several days this way and sometimes a week, but they get worse the whole time.
3. Check each one before it is opened.A live oyster is tightly shut, or closes if you tap it. Discard any that gapes and stays open, any that is cracked, and any that feels unusually light or rattles. An open oyster is a dead oyster and dead oysters are not eaten raw.
4. Set up the hold before you pick up the knife.Fold a thick tea towel several times and lay the oyster on it cup-side down, flat shell up, hinge pointing towards you. Fold the towel over the top so your holding hand is behind cloth rather than in front of the blade. This is where injuries are prevented.
5. Find the hinge.The pointed narrow end, where the two shells meet in a small notch. It is a ligament, not a fused joint, and it is the only place the shell opens without force.
6. Push in and twist — do not lever.Work the knife tip into the hinge with steady pressure and a slight wiggle until it seats, then twist the handle like a key. The shell pops. Levering with the blade is what snaps knives and what puts them into hands.
7. Cut the muscle off the top shell.Slide the blade flat along the inside of the top shell to sever the adductor muscle, keeping the blade pressed up against the shell rather than down into the oyster. Lift the top shell away.
8. Free the oyster and check it.Run the blade under the oyster to cut the bottom muscle so it lifts cleanly. Pick out any shell fragments. It should sit in clear liquor and smell of the sea — cloudy liquor or any sour smell means bin it.
9. Serve or cook, and decide honestly which.Raw on ice with lemon or a shallot vinegar. Or grill them with butter and breadcrumbs, or deep-fry them — cooked oysters are excellent and the risk essentially disappears with proper cooking.

Tips

• Never shuck without a glove or a folded towel. A short oyster knife is designed to be blunt precisely so it needs pressure, and pressure plus a slip is how it ends badly.
• Open oysters to order rather than in advance. They lose their liquor and their texture within minutes.
• Sitting them on ice in the fridge for half an hour before opening firms them and makes the hinge easier to find.
• The first three are always the hardest. Buy a dozen the first time so you have room to be clumsy.
• If you drop shell fragments into the oyster, rinse it in its own liquor strained through a sieve rather than under the tap, which washes the flavour away.

Common mistakes

• Using a kitchen or paring knife — They are thin and flexible and they snap under twisting load. An oyster knife is short, thick and blunt because the job is prising, not cutting. They cost very little.
• Trying to force the blade in at the side — The shells overlap and interlock everywhere except the hinge. Attacking the side takes far more force, shatters the shell edge into the meat, and is the main cause of slips.
• Judging safety by smell — Norovirus does not smell, does not change the appearance and is not killed by lemon juice, vinegar, alcohol or chilling. A perfect-looking, perfect-smelling oyster from contaminated water will still make you ill.

Questions people ask