Question

what are methods used to measure ingredients and their units of measure?

Answer 1

An ingredient is (almost) always an item in a recipe. Therefore it takes up space, and to measure it, it must be put into something that will hold the amount the recipe calls for. So an ingredient takes up space and has volume. Ingredients in recipes are measured either by the volume or weight. So the units of liquids (cup, pint, quart, gallon) apply; or the units of weight (ounce, pound) apply. The units of weight correspond (roughly) to the units we use for dry measure: teaspoon, tablesspoon (1 ounce), cup (8 ounces) of the ingredient. Generally, whatever unit of the ingredient you need, it is leveled at the top of the container that holds it. Obviously you don't have to do any leveling with a liquid unit, but you do with a dry or semi-solid (butter, shortening) one. Measuring by weight is ultimately the most accurate, but is not necessary nor practical for most home recipes, though it can be critical when making large amounts. Different types of flour, for instance, have different weights per cup.

The most accurate recipes rely on the measurement, grams of mass. Volume measurements are erroneous. Look at purchased commercial food. The Food and Drug Administration requires gram measures.