Why do Americans measure everything in cups?

Chris@feddit.uk to No Stupid Questions@lemmy.world – 198 points –

Used a couple of US recipes recently and most of the ingredients are in cups, or spoons, not by weight. This is a nightmare to convert. Do Americans not own scales or something? What's the reason for measuring everything by volume?

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Because it's quicker to just use a measuring cup than by weighing it out every time, I assume.

I do have a scale, but I mostly use it when portioning out a big chub of ground turkey or beef.

If you'd use metric, then weight & measurements on measuring cups would be basically the same. Like, 1 liter or milk or water is exactly 1 Kg. Using arbitrary measurements like "cups" or "feet" are just confusing and prone to error.

Milk has a specific gravity slightly higher than 1, so that isn't accurate.

Also, "cups" and "feet" aren't arbitrary. They aren't part of the metric system, but a cup is a standardized unit of volume and a foot is a standardized unit of length.

Exactly. How is a foot anymore arbitrary then a meter?

Or a cup anymore arbitrary then an ounce?

Imperial measurements were based on arbitrary things, metric has specific scientific definitions for their weights.

1l of water is 1kg at sea level, why the fuck is kings foot size the defacto foot?

Imperial measurements were based on arbitrary things, metric has specific scientific definitions for their weights.

What do you mean? A pound is legally defined as 0.45359237 kilograms.

And the kilogram is defined:

The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015Ɨ10^āˆ’34 when expressed in the unit Jā‹…s, which is equal to kgā‹…m^2 ā‹…s^āˆ’1, where the metre and the second are defined in terms of c and Ī”Ī½Cs.

These are all currently defined off of the same universal constants, just with different multipliers, which are all arbitrary numbers: 6.62607015 is just about as arbitrary as 0.45359237. Hell, the number 10 is arbitrary, too, so we still use a system for time based on dividing the Earth's day into 24 and 60.

Like, I get that there's some elegance in the historical water-based definitions derived from the arbitrary definition of length, but the definition of "meter" started from about as arbitrary a definition as "foot" (and the meter was generally more difficult to derive in the time of its adoption based on the Earth's dimensions).

Iā€™ll nitpick that said definition is also arbitrary. Why is it 1l of water at sea level, and not molecular weight of the water? And why a Liter anyway.

Even metric units like time are somewhat arbitrary. Why is a second based on caesium frequency, and not some other element?

Iā€™ll nitpick that said definition is also arbitrary. Why is it 1l of water at sea level, and not molecular weight of the water? And why a Liter anyway.

Why? Because 1L is 1000 Cubic centimeters, which takes 1000 calories to raise 100 degrees to boiling point.

Nothing is arbitrary with metric, everything is also directly related to every other measurement.

Because 1 Drakon is 1000 Cubic 100tholians, which takes 1000 Vornies to raise 100 degrees on the Flugar scale to boiling point.

Metric is very scientific, but it was made through arbitrary means. They chose to make it easier than imperial by using divisions of 10. But it's all based on a single measurement that they made up through arbitrary means.

"We have this length called a meter. How do we define it? Let's use it to measue something in nature and then use that measurement to define it."

If you have to ask that you have no idea how metric works

Until a few years ago, a kilogram was defined by a block of metal.

From 1799 to 1960, the metre was defined by another block of metal. Before 1799, it was defined by a measurement that was hard to verify.

That kind of sounds arbitrary.

On March 30, 1791, the French Academy of Sciences defined the length of a meter. Before this date, there were two definitions to this measure of length: The first was based on the length of aĀ pendulumĀ and the second was based on a fraction of the length of a half-meridian, or line ofĀ longitude. The French Academy chose theĀ meridianĀ definition. This defined one meter as one ten-millionth of the distance from theĀ EquatorĀ to theĀ North Pole.

The meter is the basic unit of distance in the International System of Units (SI), the worldā€™s standardized system ofĀ measurement. Since the 1960s, all countries have adopted or legally recognized the SI. As a universal standard of measure, the meter helped ease the exchange ofĀ commerceĀ and scientificĀ data.

However, the definition of a meter has changed since 1791. In 1983, the meter got its current definition. The meter is defined as the length of the path travelled by light in aĀ vacuumduring a time interval of 1/299,792,458 of a second.

The meter was never to do with metal, and every metric definition is scientifically found, not based off of someoneā€™s foot.

You are way overthinking this.

Also, a foot is just a scientific as any other definition as long as you use the same foot every time.

Can you get me All of the things that I would need to Measure the speed of light in a vacuum, then do the math to divide all that?

Because that is what the average layman would need to verify what a meter is.

Also, a foot is just a scientific as any other definition as long as you use the same foot every time.

That king is looooooong dead

And yet if we were to take something and make it the same length, We would have a rule about how long it was.

We could even call it something like a ruler, or whatever the metric equivalent of a yardstick is, a meter stick maybe.

And than what happens when itā€™s destroyed? You donā€™t have anything to verify it with, and using a rulered rule to rule will lead to progressively larger deviations from the true original.

This isn't any different from metric systems. If all meter sticks are destroyed, then what do you do? Build everything up again to be able to measure the distance travelled by light in a vacuum in 1/299,792,458 seconds. The procedure would be exactly the same for feet, except you measure the distance travelled in 0.3048/299,792,458 seconds.

I donā€™t disagree with you really, I just think youā€™re overthinking it.

It just doesnā€™t matter in 99.99% of cases and for the ones that it does we have metric.

Do I wish more things in life were metric?

Fuck yes I do, I hate fractions so much, like not normally but when it comes time to have to do a conversionā€¦

A fraction of the Earth's diameter isn't a sound scientific reasoning to define a length. And after that, the definition reverted back to a similar definition of a foot, a fixed length of an item, similar to a foot.

The two main benefits of the metric system are the decimalized behavior of its units and that the scientific community adopted it early, creating additional units from the standard and allowing for greater precision of the initially defined units over time.

However, the value in the meter being its length is the same as everyone agreeing the Prime Meridian goes through Greenwich, UK; it is because everyone agrees to it.

Milk has a specific gravity slightly higher than 1, so that isnā€™t accurate.

In this context milk is a bad example because the difference between 1.03g/ml and 1g/ml is negligible in a kitchen. Even oil (0.92g/ml) is close enough.

This matters the most for stuff like below (with 1cup = 240ml):

  • honey: 340g/cup = 1.4g/ml
  • sugar: 200g/cup = 0.85g/ml [varies depending on granularity]
  • flour: 120g/cup = 0.5g/ml [sieved, and "properly" measured. It's a PITA to measure it by volume.]

Also, ā€œcupsā€ and ā€œfeetā€ arenā€™t arbitrary.

All units are arbitrary, be them metric or esoteric.

In this context milk is a bad example because the difference between 1.03g/ml and 1g/ml is negligible in a kitchen. Even oil (0.92g/ml) is close enough.

The context is that if you are going to hand wave away a 3% difference in a quantity, then having to weigh everything probably isn't important.

The context [SIC - rationale] is that if you are going to hand wave away a 3% difference in a quantity, then having to weigh everything probably isnā€™t important.

That's poor reasoning; ignoring a tiny difference doesn't imply ignoring larger ones. Myself mentioned three cases where the difference matters, with one (flour) being highly variable.

A better argument to defend your point would be that most differences in the kitchen are tiny.

I've been making that argument in other comments. If I had to argue the nuances of this argument in every comment, I'd be copying and pasting pages long comments that no one would read.

It's close enough for home cooking, the specific gravity of milk is around 1030g/L so unless your recipe calls for multiple liters of Milk the small difference isn't going to affect the result.

It's close enough for home cooking

And now you are getting to the reason why American use volume for recipes. If I don't need the precision of mass for recipes as it won't appreciably affect the taste, then why break out the scale?

Because the difference between packing a cup of flour and not packing a cup of flour is as much as 30%

https://www.loveandoliveoil.com/2020/01/weight-vs-volume-measurements-in-baking-and-the-best-way-to-measure-flour.html#:~:text=So%20depending%20on%20how%20you,of%20150%20grams%20(!!)

It doesn't really matter for liquids, but dry ingredients are a whole other ballgame when it comes to this mess.

Itā€™s really mainly only flour though, because can be compacted, most of the things that youā€™re using in the kitchen like baking powder or sugar arenā€™t going to be compacted to any appreciable level.

For flour, you pour it into your measuring cup and then run the spine of a knife or something over it to get rid of the excess flour and get a level cup

There are many of other things that can be compacted or have different volume to weight ratios.

Corn starch is like flour, you can pack it down.

Salt (Table vs Kosher) Kosher salt has about half the volume to weight as table salt.

Shredded Cheese (this one always bugs me. Is it 3 cups after shredding, or before... how packed in should it be), etc.

A lot of volumetric baking recipes tell you to run the grain through a sieve to remove clumps, this generally standardizes the density well enough.

Salt is usually assumed to be table salt unless noted in the recipe. Even then, most recipes have a point to them where they tell you to taste the food and add salt to taste as necessary.

What are you cooking with shredded cheese where the ratio is that important?

Are you measuring cornstarch?

Maybe I just have weird cornstarch but anytime I try to actively scoop out of it, itā€™s like trying to scoop baking powder.

I use it frequently in coatings for Japanese deep fried foods, usually mixed with flour and salt in particular ratios.

In my other responses, I've noted that I don't bake. In other people's responses, they've noted that there are still a lot of baking recipes out there that don't require precision.

Precision in baking is massively overstated. The earliest recipes are in parts if you're lucky. More likely they are mix in these ingredients until it looks right.

Elevation changes everything though and if you donā€™t adjust the measurements change more.

If youā€™re at sea level, sure.

1 liter of milk weighs more than 1 kilo. Milk is denser than water therefore 1 liter of it has to weigh more than water.

Edit: I just looked it up and 1 liter of milk is 1.03 kilos.

Well since we're nitpicking, a kilogram is a unit of mass, not weight. So unless by "kilo" you meant kilonewtonā€¦

Water isn't the only ingredient. One liter of flour is not nearly one kilogram. More importantly, the mass of one liter of flour varies a lot depending on how much it settled in the container. That's why weight is always the better way to measure ingredients.