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Comment by dsq | Hacker News Reader

Cup is a universal measure of volume. It works for flour, sugar, liquids. Whereas grams is different volume for each material and requires a scale. I suppose one could use a metric quantity, but 'liter' is too big and 'deciliter' is too small.

I am a non-USian, but still think that 'cup' is the best measure of volume for cooking/baking.

And there is a compromise! Most of the measuring jugs I buy have cups on one side, and common materials in grams on the other. So there is no real problem.

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Liquids can be accurately measured by weight. The converse is not true -- powders cannot be accurately measured by volume. 2 tsp of kosher salt contains the same amount of salt as 1 tsp of fine salt. And every brand is slightly different. The only way to accurately know if you're using the same amount of salt as the recipe developer is if the measurement is by weight.

Then there's the people who write recipes telling you to chop 1 cup of a vegetable, or "X medium-sized Ys". I never understood the aversion some people have to weighing things.

They are eyeballing everything, then have to make a recipe out of it. The recipe didn't include all of the "fixing" of the spice/salt balance they do during cooking.

Weight also opens up question. Is that pre or post preparing? Like removing parts or skins and so on?

That’s interesting. I’ve never once thought of weighing (or measuring by volume) something before chopping it up. Maybe I’m just not thinking of the right ingredient?

For me, weight solves one of the biggest issues which is “large potato” or “large onion”, WTF is “large”?

> 2 tsp of kosher salt contains the same amount of salt as 1 tsp of fine salt.

The article makes a similar point about unrefined brown sugar and caster sugar, but something doesn't sit right with me for that. Shouldn't the packing densities of sugar/salt crystals, and therefore the mass densities, be the same at different scales? So unless the volume you're measuring is within an order of magnitude of the size of the objects being measured, where edge effects become significant, shouldn't they contain about the same amount?

(Even the grains of coarse salt shouldn't be significantly more than 1/10 of the width of a teaspoon, no?)

No, because they have a different internal crystal structure with more space. The kosher salt is, to use a vague term, more fluffy. There's a photograph in this Cooks illustrated article, if you go to the end of it and click read more: https://www.americastestkitchen.com/taste_tests/2109-kosher-...

The article also points out that the salt structure differs not just between table salt and kosher salt, but between kosher salt manufacturers depending on the process they used to make it. Weight wins.

I see what you mean but that only works in the assumption of crystals being the same shape and point size probability distribution. Which is a reasonable assumption for crystals but real materials are derived by grinding, so you can easily have a wider distribution of shapes (rounder) and sizes (small particles filling the gaps between larger ones).

Good point but this only holds if the sugar/salt particles always have identical geometry and are just varying in scale; I think that assumption is fundamentally flawed.

> Cup is a universal measure of volume. It works for flour, sugar, liquids.

Until a recipe asks for 1-cup of butter. Tf am I meant to be, melt it down? Or 1-cup of broccoli, how does that even work?!

Grams works for everything. All the time, no exceptions.

"cups of butter" is the wildest measurement I come across regularly in US recipes.

Just... how?

Edit: A friend of mine has just related running across a US scone recipe asking for "5 tablespoons of cold butter". I don't even want to think about packing cold butter onto a tablespoon to get that measurement right!

In case you are wondering how this works in practice, American butter typically comes in "sticks". Each stick weighs 1/4 pound, and is individually wrapped in foil or paper. These wrappers are typically marked in Tablespoon increments with 8 Tablespoons (1/2 cup) per stick. Measuring Tablespoons of butter just involves looking at the markings on the stick (or visually estimating the number of 8ths) and cutting off the chunk that one needs. Measuring major fractions of cups is just counting sticks.

Also, that will greatly simplify the conversion process for me in the future.

Previously, when I've come across a US recipe requiring cups of butter, I've looked up the size of a US cup - which is given in fl.oz - converted that to ml, and then found a good estimate for the density of butter, and used that to convert to a weight in grams - which I can then measure easily.

If I'd known that "a cup of butter" was not really meant to be an actual "cup" measurement, and was actually shorthand (longhand?) for "0.5lb butter", that would have made conversion So. Much. Easier.

Seriously, wtf.

(I take it that other "cup" measurements are actually meant to be volume measurements, and I should measure cups of flour/sugar/etc... (and liquids, obviously) in volume-marked measuring containers?)

That does provide a method to the madness, thanks.

But... butter being measured in "cups" and "tablespoons", which are multiples/fractions of a 1/4lb block, is therefore fundamentally a unit of weight, not volume?!?

That's even more wild.

Butter in the USA is sold in 1-pound boxes, each containing four quarter-pound "squares" that are marked with tablespoon and fractional-cup gauges. Simply slice off five tablespoons. (There are "Eastern" and "Western" square sizes, depending on where you live.) See: https://en.wikipedia.org/wiki/Butter#Packaging

Indeed, how would you slice cold butter by grams? Is there even a procedure?

Easy. Just slice of parts into your bowl until the scale shows the desired weight. I am a bit envious of American butter packaging, because it saves so much time, but if they ever change anything about it, you are all hosed, because nobody will know what 5 tablespoons was supposed to mean. ;-)

> how would you slice cold butter by grams?

It's more sensible than slicing off butter by spoons, where a spoon is not a square, except the slice of butter is a square!

Butter stick at least in America normally have tablespoon marks on the wrapper. That said, sometimes the wrapper is clearly shifted one direction or the other so that the first or last “tablespoon“ is not a full tablespoon.

Butter sticks in the US have marks down the side of the wrapper, like a ruler, that show you tablespoon increments. Google image search "tablespoons butter stick".

In the US, our butter comes in wrappers that divide each stick into 8 tablespoons, so it's actually very easy -- you can visually see where to cut.

When a recipe asks for a cup of butter, they're not actually asking for a cup of butter. American butter comes in one pound blocks so it's likely the recipe developer actually used a half pound of butter rather than a cup. If you actually measure a cup of butter into your recipe you've likely put slightly more butter in than the recipe developer did.

But at least you'll be close. Unlike 1 cup of broccoli.

How do you measure 1 cup of broccoli? Cos that sort of instruction comes up constantly. Unless American stores sell vegetables in 1 cup bushels (which just in case they do, is beyond insane) I don't see how you could reliably do that ever.

Yes, that's such an obvious point that I didn't think I needed to make it more clear that I agree with you.

Agreed I hate volume measurements for anything that can’t be packed down or that is expected to be used in a non-liquid form (like the butter example). At least with butter, I know it means two sticks but I still prefer weight whenever possible.

I have to push back a bit on using volume to measure compressible solids like flour. If the actual mass matters, as it can in baking, measure the mass not the volume.

I don't see how cups are in any way better than desilitres. You use a larger measuring tool when you need more than say three dl. I agree that grams are inconvenient to use for flours and liquids, so litre/desilitre/millilitre just seems the logical option.

I'm obviously very biased by growing up with SI units, and having no cup measures around. Every time a recipe says cups, I sigh and use a smartphone to convert it.

According to the article a "cup" of flour is anywhere between 120g and 150g. A 5% error in measurement is enough to screw up baking, let alone a 20% error.

I agree that grams are inconvenient to use for flours and liquids, so litre/desilitre/millilitre just seems the logical option.

It works for fluids but it is complete mess for any compressible solid (flour), and even non-compressible one that comes in different grain size(salt).

On side note it would be nice to have tabletops with builtin scale...

I've got some glass and transparent plastic cups with marks at deciliters up to 500 cc. They are commonly sold at stores here in Italy. I guess its the same all around the world. Or I just fill a glass with water and weight it, empty and full. 1 liter of water at usual temperatures and pressures is 1000 grams, a convenient choice. We don't need much more precision than that to cook. Even milk can be approximated with 1 l to 1000 g.

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