Rubbery prawns

Why the window is so short

Prawn muscle is fine-grained and has almost no connective tissue and very little fat. Its proteins set quickly, and once they have set they keep contracting and squeezing water out with nothing to compensate.

A steak has fat and collagen buying it time. A prawn has neither, so the difference between properly cooked and rubbery is a matter of thirty to sixty seconds.

This is why prawns are added last to almost everything, and why a curry with prawns simmered in it for ten minutes is a curry with rubber in it.

The shape test

The most reliable doneness cue there is, and it takes no equipment.

1. A raw prawn is straight or gently curved.
2. As it cooks it curls. When it forms a loose C shape, it is done. Take it out.
3. If it curls further into a tight O, it is overcooked. The tail has tucked round to meet the head.
4. Colour helps but is less reliable: opaque and pinkish-white throughout is right, and it turns opaque before it turns rubbery.
5. Take them out a shade early. They carry on cooking off the heat, particularly in a hot sauce.
6. Very large prawns are more forgiving than small ones, which go from raw to rubber almost instantly.

How to cook them well

• Very hot pan, very short time. Ninety seconds a side for a large prawn, less for small.
• Add them at the end. In a curry, a stew or a soup, the prawns go in for the final two minutes with the heat turned down.
• Dry them first. Wet prawns steam and go pale and flabby rather than browning.
• Do not crowd the pan. Prawns release a lot of water and a crowded pan boils them.
• Shell-on where you can. The shell insulates slightly and adds a great deal of flavour.
• A brief salt or brine firms the texture and is a standard restaurant step.
• Frozen prawns: thaw them properly first, and pat them very dry. Cooking from frozen releases water into the pan.

What to do with rubbery ones

Chop them finely

Into a fried rice, a fishcake or a filling, where texture matters less.

Into a bisque or a stock

The shells and heads are worth more than the meat here anyway.

A prawn cocktail

Sauce and lettuce disguise a great deal.

Not re-cooked

There is no second cook that softens them.

Safety

Rubberiness is a texture fault, not a safety one. How thoroughly meat, poultry and fish should be cooked, and how they should be stored, chilled and reheated, are food-safety questions rather than culinary ones. FoodHQ publishes no temperature, time or storage window for them — follow current Food Standards Agency guidance.

Common questions