Cooking weights and measures
In recipes, quantities of ingredients may be specified by mass (commonly called weight), by volume, or by count.
For most of history, most cookbooks did not specify quantities precisely, instead talking of "a nice leg of spring lamb", a "cupful" of lentils, a piece of butter "the size of a small apricot", and "sufficient" salt.
In the US, Fannie Farmer introduced the more exact specification of quantities by volume in her 1896 Boston Cooking-School Cook Book.
In most of the world, recipes use the metric system of units—litres (L) and millilitres (mL), grams (g) and kilograms (kg), and degrees Celsius (°C).
In Australia, since 1970, metric utensil units have been standardized by law, and imperial measures no longer have legal status.
In Europe, older recipes frequently refer to "pounds" (e.g. Pfund in German, pond in Dutch, livre in French).
Water at 4.0 °C (39.2 °F) may be volumetrically measured then weighed to determine an unknown measuring-utensil volume[13] without the need for a water-density adjustment.
From units and tools of convenience, most of the system's history could have values vary widely, and was not until recent centuries that standardization began to take shape.
* Discrepancies due to size, generally disregarded as at the scale it becomes a factor, the person generally is using the next size up measuring cup (i.e.: 1+1⁄2 fl oz is likely to be straight measured in an ounce cup and not as 9 (vs 12) teaspoons) ‡ Rare if not nonexistent in use by name rather than as fraction of a different unit.
The saltspoon most likely combined into the scruple over time, as a consequence of home cooks approximating standard measures with what they had at hand, much as the teaspoon was roughly "close enough" for a kitchen approximation to a fluid dram (= 60 minims), but not equal to the 1+1⁄3 fl dr (80 minims) value it actually is; especially with the variability of the method of measuring itself.
Not of insignificance is the natural habit of customary measures to use a 2n dividing scheme regardless of exact definitions, and this pattern is seen even with metric measuring spoons Confusion comes about from teaspoon continuing to be called a "dram" in vernacular, despite the sizes of actual spoons creeping up quietly over time, such that 1⁄4 of a tsp (tsp > fl dr) would in fact become congruent with current 1⁄3 fl dr values for the scruple and saltspoon; in other words, the terminology not keeping pace with the definition.
At the small scales involved this is negligible (i.e.: math can convert down to tsp ×10−9, but to what degree can it practically be meted); however can cause problems when accuracy is required such as medicines: "In almost all cases the modern teacups, tablespoons, dessertspoons, and teaspoons, after careful test by the author, were found to average 25 percent greater capacity than the theoretical quantities given above, and thus the use of accurately graduated medicine glasses, which may be had now at a trifling cost, should be insisted upon.
There are a variety of approximate units of measures, which are frequently undefined by any official source, or which have had conflicting definitions over time, yet which are commonly used.
The measurement units that are most commonly understood to be approximate are the drop, smidgen, pinch, and dash, yet nearly all of the traditional cooking measurement units lack statutory definitions, or even any definition by any organization authorized to set standards in the U.S. For example, of the table above, only the fluid ounce, pint, quart, and gallon are officially defined by the NIST.
The imperial gallon was originally defined as 10 pounds (4.5359 kg) of water in 1824, and refined as exactly 4.54609 litres in 1985.
Traditionally, when describing volumes, recipes commonly give measurements in the following units: If the recipe is one that has been handed down in a family and gives measurements in ‘cups’, it is just as likely to refer to someone's favourite kitchen cup as to the said unit that is 6 fluid ounces.
British cookery books and recipes, especially those from the days before the UK's partial metrication, commonly use two or more of the aforesaid units simultaneously: for example, the same recipe may call for a ‘tumblerful’ of one ingredient and a ‘wineglassful’ of another one; or a ‘breakfastcupful’ or ‘cupful’ of one ingredient, a ‘teacupful’ of a second one, and a ‘coffeecupful’ of a third one.
For smaller amounts, British recipes traditionally give measurements in the following units: For even smaller amounts, the following units are used: American cooks using British recipes, and vice versa, need to be careful with pints and fluid ounces.
In September 2007, the EU with Directive 2007/45/EC deregulated prescribed metric packaging of most products, leaving only wines and liqueurs subject to prescribed EU-wide pre-packaging legislation;[35][36][37] the law relating to labelling of products remaining unchanged.
[38] Some volume-based recipes, therefore, attempt to improve the reproducibility by including additional instructions for measuring the correct amount of an ingredient.
