How much pasta salad for 50 people

Sixty grams of dry pasta a head. Pasta salad is a side dish among others, not a main course, and dry pasta roughly triples in weight as it cooks — so 3 kg dry becomes about 9 kg in the bowl, which looks like an enormous amount and is the right amount for fifty.

Dress it twice, and this is the part almost everyone gets wrong. Cooked pasta keeps absorbing dressing as it sits, so a salad that was perfect when you made it is dry and dull four hours later. Dress it with half when it is still slightly warm, refrigerate, then add the rest and a splash of vinegar just before it goes out.

Cook the pasta one minute past al dente, not to it. Cold pasta firms up considerably, and something perfectly al dente hot is unpleasantly hard straight from the fridge. Rinse it under cold water afterwards — the one time rinsing pasta is correct, because you want to stop the cooking and wash off the starch that would glue it into a block.

Short shapes with texture hold dressing: fusilli, farfalle, rotini, penne. Long shapes tangle and smooth shapes shed. And salt the water properly even though it is a cold dish — 10 g a litre, and it is the only chance you get to season the pasta itself rather than what is on it.