The full guide
Read straight through, or use the seafood notes above to keep buying, cooking and serving simple.
How to Cook a Live Lobster
IMPORTANT...
Make sure that your lobster is still alive before cooking it. When a lobster dies bacteria will quickly destroy the meat so it is important to either cook the lobster while it is still alive or immediately after it has died.
A lobster that has limp claws or whose tail does not curl when you pick it up is close to death and should be cooked immediately.
Getting your lobster in advance
There will be occasions when you catch or buy a lobster in advance. This is not a problem if the lobster is less than 48 hours before you are planning to eat it and providing your lobster is lively (see above).
You can keep a lobster alive in the fridge for up to 48 hours or you can cook it immediately and then keep the cooked lobster in the fridge for 48 hours (the latter is our preferred option).
To keep a lobster alive in the fridge
Place lobster in large bowl or container
Cover the lobster with wet seaweed - if this is not possible you can use a tea towel soaked in salt water. Do not use fresh water as this will kill the lobster
Place the lobster in the fridge for up to 48 hours making sure that the seaweed or tea towel is kept damp with sea water.
How to cook a lobster humanely
Nobody likes the thought of killing something and many people, including chefs, do not like cooking live lobsters. While commercial shellfish processors are now required to use a stun gun to kill shellfish, this is not the case for domestic consumers.
The current guidance by Seafish, working alongside the Shellfish Association of Great Britain (SAGB) and the Crab and Lobster Management Group (CMG) is as follows:
"In terms of despatch at home by consumers, current advice is that lobsters should not be boiled alive (either by placing in cold water which is raised to a boil or already boiling water). Instead lobsters should be put in the freezer for 30-60 minutes, before being placed immediately into boiling water. Alternatively they may be split lengthways (along the longitudinal midline on its underside) to destroy all their neural centres before cooking. This can be done by swiftly plunging a sharp knife straight down into the carapace behind the lobster's eyes, right below where the claws meet the body and halfway to the first joint. The knife should then be pulled through the entire body (but tail is not necessary) to split the animal’s carapace in half all the way down its body. Care should be taken when doing this with fingers kept out of the way! These two techniques can be combined, with the knife inserted into the lobster after 1-30 minutes in the freezer." - Seafish UK 03.08.22
We will monitor this and change the advice should anything change.
For more information about shellfish welfare please visit https://www.seafish.org/about-us/news-blogs/seafood-industry-focuses-on-crustacean-welfare/
How to Cook a Lobster
Either despatch the lobster using a knife or put it in the freezer for 30-60 minutes (see above)
Make sure you have a large enough pan so that the lobster will fit into it easily and be fully submerged.
Put a large pan of water on the hob and bring to the boil - the water should be at a rolling boil (100°C / 212°F)
Pick up the lobster by its back and place into the water claws and head first.
Use our guide to determine how long to cook the lobster.
Lobster Cooking Times
Imperial
Metric
Cooking Time
1 - 1 ¼ lb.
500g
12 - 15 mins
1 ¼ - 2 lb.
500g-900g
15 - 20 mins
2-3 lb.
900-1350g
20 - 25 mins
3-7 lb.
1350-3kg
25 - 30 mins
Over 7lb
Over 3kg
3 mins per lb / 500g
You will know that the lobster is cooked by checking the following:-
The lobster should be red in colour and if you pull gently on one of the small back legs or one of the antenna it should come away easily.
Remove the lobster from the water and leave to cool
Do not be tempted to over cook the lobster as over cooking will cause the meat to become tough
Tools for serving lobster
The crackers, picks and shears that make the final preparation easier at the table.
Common questions
- How do you kill a lobster humanely?
- Seafish advise against boiling a lobster alive. Either chill it in the freezer for 30 to 60 minutes then place it into boiling water, or split it lengthways with a sharp knife straight down through the carapace behind the eyes to destroy the neural centres. The two methods can be combined.
- How do you keep a lobster alive before cooking?
- Keep it in the fridge for up to 48 hours, covered with damp seaweed or a tea towel soaked in salt water. Never use fresh water, as that will kill the lobster.
- How long do you cook a lobster?
- By weight: roughly 12-15 minutes for 500g, rising to 25-30 minutes for a 1.35-3kg lobster, then about 3 minutes per 500g above that. The water should be at a gentle boil, around 100°C.
- How do you know a lobster is cooked?
- The shell turns red, and a small back leg or antenna pulls away easily. Do not be tempted to overcook it, as the meat will toughen.
- Which way up does the lobster go into the pan?
- Hold it by its back and lower it into the water claws and head first, making sure the pan is large enough for it to be fully submerged.









