An oversalted dish may not be the recipe's fault. According to a cooking source, the culprit is often the brand of kosher salt used, because different brands vary significantly in density. The source, updated in 2021, notes that recipe testers frequently use Diamond kosher salt, and cooks who substitute other brands by volume can end up with a much saltier result.
The source provides basic weight equivalencies: 1 teaspoon of table salt weighs 6 grams; 1 teaspoon of Diamond kosher salt weighs 2.8 grams; 1 teaspoon of Morton kosher salt weighs 4.8 grams; and 1 teaspoon of David kosher salt weighs 6 grams, the same as table salt. In terms of saltiness, 1 teaspoon of table salt equals about 2⅛ teaspoons of Diamond; 1 teaspoon of Morton kosher salt equals about 1¾ teaspoons of Diamond; and 1 teaspoon of David kosher salt equals about 2⅛ teaspoons of Diamond.
The source advises against hunting down Diamond brand if it is unavailable or expensive. Instead, it suggests assuming a recipe tester used Diamond and, when using another brand, starting with half the amount called for. Salt can always be added later, the source notes, but it cannot be removed once incorporated.
Editorial Notes