Kosher salt

One US cup of kosher salt weighs between 128 and 256 grams, depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Kosher salt is the exception on this site that requires its own entry structure. Unlike table salt or granulated sugar, where different brands weigh essentially the same by volume, kosher salt from different manufacturers weighs dramatically different amounts for the same volume. This is not a measurement disagreement; it is a genuine physical difference in the crystals themselves.

King Arthur publishes 1 tablespoon of Morton's kosher salt at 16 grams and 1 tablespoon of Diamond Crystal kosher salt at 8 grams. That is a factor of two — the same nominal ingredient at half the weight per volume, from one brand to the other. Both figures are in King Arthur's ingredient weight chart alongside table salt, listed as separate rows because they behave as separate ingredients.

America's Test Kitchen has published their own weighed measurements: 1 teaspoon of Morton's = 4.8 grams and 1 teaspoon of Diamond Crystal = 2.8 grams. These extrapolate to 230 grams per cup for Morton's and 134 grams per cup for Diamond Crystal.

The two sources agree within 5 percent on Diamond Crystal (128 g/cup from King Arthur, 134 from America's Test Kitchen). They disagree by about 10 percent on Morton's (256 g/cup from King Arthur, 230 from America's Test Kitchen), which is over the 5 percent tolerance we apply to the sugar category. We publish Morton's as a range for that reason. Diamond Crystal is published as a single figure from King Arthur, with America's Test Kitchen as the corroborating second source.

Morton's kosher salt has small, dense, roughly cubic flakes. The flakes pack tightly and behave in a measuring spoon much like table salt, though at lower density. Diamond Crystal kosher salt has larger, hollow, pyramid-shaped flakes formed by the traditional Alberger evaporation process. The flakes bridge and stack loosely, trapping air in the packed volume. The result is roughly half the bulk density of Morton's for the same volume.

The practical consequence is severe. A recipe developed with Diamond Crystal and cooked with Morton's, using the same volume of salt, will be roughly twice as salty as the developer intended. In the reverse direction, using Diamond Crystal for a recipe developed with Morton's will produce food that tastes flat. Professional kitchens standardise on one brand precisely for this reason. Serious Eats, Bon Appetit, and the New York Times generally specify Diamond Crystal when a brand is stated; older regional publications and Simply Recipes more often assume Morton's.

The commonly cited substitution ratio approximates these figures: 1 teaspoon of table salt equals roughly 1.5 teaspoons of Morton's kosher or 2 teaspoons of Diamond Crystal. Morton's is about two-thirds and Diamond Crystal about half the density of table salt when measured by teaspoon. These are working ratios rather than exact conversions and can shift by 10 to 20 percent depending on how each salt is scooped.

USDA FoodData Central does not publish a generic kosher-salt entry. The branded-foods database contains individual product records (Morton Coarse Kosher Salt: 1/4 tsp = 1.2 g; Diamond Crystal Kosher Salt: 1/4 tsp = 0.7 g), but these are aggregated manufacturer nutrition labels rather than laboratory measurements. Manufacturer labels round to FDA labelling rules and are treated as reference material on this site rather than as primary sources.

Neither the FDA salt identity standard (21 CFR 100.155) nor the Codex food-grade salt standard (CXS 150-1985) distinguishes kosher salt from other salts by density; both address purity, sodium chloride content and iodisation. Kosher salt is not defined by composition — it is chemically the same sodium chloride as table salt. The name refers to its historical use in koshering meat (drawing out blood before cooking) and is not a certification of the salt itself.

The category here is 'sugar' rather than 'milled' because kosher salt is crystalline rather than a milled powder. The 5 percent category tolerance applies within each brand's own state; the entry uses a separate state per brand precisely because cross-brand variation is far larger than any measurement error or scoop-to-scoop variation within one brand.