Table salt, kosher salt and flaky finishing salt are all mainly sodium chloride. What changes in a recipe is the crystal: its size, shape and how tightly it packs into a spoon.
Weight is the stable measurement
Ten grams of one plain salt can replace ten grams of another far more predictably than one teaspoon can. Fine crystals pack closely; large hollow or irregular flakes leave more air between them. Two brands sold under the same “kosher salt” description may therefore differ substantially by volume.
Timing changes what salt does
Salt added early can season water throughout a food and draw moisture from surfaces. Salt sprinkled at the table gives concentrated flashes of flavour and texture. A delicate finishing flake is wasted when dissolved in pasta water, while dense table salt can feel harsh as a final garnish even when the total weight is modest.
Iodised, sea and mineral salts
Iodised salt supplies iodine and may include anti-caking agents. Sea salt describes origin, not one crystal size or guaranteed mineral profile. Pink and other coloured salts contain trace minerals, but their practical role in ordinary recipes is still salting. Treat strong claims about purity or health separately from their culinary use.
How to substitute safely
Use the recipe's named brand when precision matters, otherwise convert by weight and adjust at the end where the food is safe to taste. In fermentation and curing, keep the specified concentration: salt there controls more than flavour.
