Weights and measures

Weights and measures

<rant>

One of my pet peeves with cooking recipes is that, in the majority of cases, the quantities are wrong. There seem to be two reasons for this:

1. The cooks cook first, and then later try to guess what they put in. In many cases they're badly wrong.
2. The quantities given are ambiguous or local. One of my favourites is in the Sarawak Salvation Army Boy's and Girl's Home Cookery Book, published in Kuching in 1968. The recipes are good, but this extract from a recipe for coconut shoot and chicken curry, by Wee Bee Siok, gives the idea:

   1	chicken weighing 2 to 3 katis (cut up)
   3 to 4 katis	coconut shoots
   ...
   5 sticks	lemon grass
   10 cts	ground or powdered turmeric

   “cts” is an abbreviation for “cents”: in other words, use the amount of turmeric that you could buy with MYR 0.10 in Kuching in 1968. At the time, it may have been helpful; nowadays it's just plain guesswork.

It's not only recipes from the end of Colonial Borneo that give you this kind of problem. Particularly English language recipes use units that are confusing to the point of uselessness. Here are some that particularly irritate me:

The law

The law of Moses is probably the oldest law on this subject. Deuteronomy 25:14 states:

25:14 You shall not have in your house alternate measures, larger and smaller.

Clearly the background here is the use of the alternate weights for cheating others, but it doesn't say so in the law. So is this illegal?

About the only reason I can find why it should not be is because it's only a single measure.

Cups

I've established that a cup can have at least one of the following volumes:

• 65 ml (a normal Italian Espresso cup).
• 84 ml (the “small cup” size on my coffee machine). I measured this from the scale on the side: this is the amount of water that goes into the machine. A few millilitres probably get lost in the brewing.
• 90 ml (another, ornate Espresso cup that I have).
• 100 ml (in the instructions of the coffee machine referred to above, “normal cups”). It must be referring to the 84 ml cups. It's interesting to note that even the instructions diverge from the actual measurements on the device. Apart from that, these sizes seem to be standard misconception amongst coffee machine makers. I've never seen a cup to match, and I suspect it's so that they can sell a 6 cup coffee maker as a 12 cup device. This seems all the more plausible given that other coffee machines I've seen seem to have a “small” size of 100 ml.
• 105 ml (the “large cup” size on my coffee machine, as measured).
• 125 ml (in the same coffee machine instructions, “European cups”, presumably referring to the size that actually gives 105 ml). I've never seen a cup of this size, either.
• 150 ml, seen on a packet of Indian chicken tikka masala mix.
• 200 ml (a real tea or coffee cup, made in “Europe”). This bears a good relationship to the smaller coffee machine cups, unless the manufacturer lies: for every cup you want to drink, you select two in the coffee machine.
• 225 ml. I forget where this is, but I found it in one cookbook.
• 236.6 ml, an “American Cup” (about half a pint). Marked on a set of measures I have (see below).
• 238 ml, an “American Cup” (about half a pint). Noted in multiple cookbooks.
• 240 ml, an “American Cup” (about half a pint). Defined by law
• 250 ml, an Australian “metric cup”.
• 284 ml, a “British Cup” (half a pint). Noted in multiple cookbooks. This is a little more than the volume of a coffee mug, which I consider to be considerably larger than a “cup”.

Despite all that, many cookbooks specify ingredients in “cups”, even when it's easier to weigh them. One reason might be that in the USA, the law (dated 1 April 2004, but presumably meant seriously) makes it the preferred form of measure:

    (i) Cups, tablespoons, or teaspoons shall be used wherever possible
and appropriate except for beverages.  For beverages, a manufacturer may
use fluid ounces.

And yes, the wording of that sentence is original, as I pulled it off the web site.

As noted above, even in the USA, the sizes aren't uniform. The same law defines a teaspoon as 5 ml and a cup as 240 ml; I've discovered measures which somehow found their way into my house in Australia, but appear to be an older US measure which equates a cup to 236.6 ml and a tablespoon to 14.79 ml:

Certainly not everybody has kitchen scales, but the inaccuracies inherent in misinterpreting “cups” are ridiculous, and even if you do guess correctly, you'd need multiple different cups to measure them. If you don't have scales, a direct volume (“300 ml” or “9 fl. oz.”) would be much less error-prone. The use of “cups” for cooking measures is a uniquely English language thing; none of my cookbooks in other languages use cups, and why should they? Given the potential inaccuracies, it's just plain stupid.

In the case I referred to, It would have been tempting to go for the Australian cup, since we're in Australia, but the package showed the weight in ounces, something that wouldn't happen here. In the end we made a toss-up between US and British, and went with 500 ml. That proved to be wrong: we had to add more water. I suppose we should have taken the British cups. But why does “Panni” do something that stupid? In the German version I'm sure they have the correct volumes.

Spoons

Many recipes also use terms like “teaspoon” (abbreviated tsp or teasp.) and “tablespoon” (usually abbreviated Tsp or tbsp., just to keep you on your toes). Some also use “dessertspoons” and sometimes abbreviate them “dessertsp.”. Again, their quantity varies; in addition, it's very difficult to find a spoon as big as the average “tablespoon”. Here's what I measured, compared with values gleaned from various cookbooks. It seems that, like the US measures, the Australian measures have some kind of official sanction, more's the pity. Maybe the others do too.

	My	Australian
Spoon	measured	(“metric”)	UK	US
	Volume	standard	standard	standard
Teaspoon, kitchen	2.5 - 4 ml	5 ml	5 ml	5 ml
Teaspoon, serving	4.5 ml	5 ml	5 ml	5 ml
Dessertspoon			10 ml
Tablespoon, serving	11 ml	20 ml	15 ml	15 ml
Tablespoon, large kitchen	17 ml	20 ml	15 ml	15 ml

The important thing to note here is that the measures are usually smaller than you'd expect, in the case of Australian tablespoons nearly 50% less.

Other problems with volumetric measure

It's not enough to establish the volume of solids, of course: their shape can have considerable effect on the volume. For example: “1 tsp cloves, ground”. How much is that? If you take the tsp of cloves and then grind them, you won't get a tsp of ground cloves. Indeed, depending both on the shape of the tsp and the size of the cloves, the weight can vary considerably. But it's the weight that makes the difference, not the volume at some point during the processing.

In addition, measuring teaspoons is a very inaccurate business. Four “teaspoons” measured with the measure shown in the photo above, make almost exactly 30 ml:

That's 50% more than indicated.

Making a cup of coffee

To confuse things still more, the package of the coffee I drink (Melitta “German Premium”), as sold in Australia, recommends: “Use one heaped dessert spoon per cup, or vary according to taste”.

In Germany, there are special measuring spoons for coffee. They're intended to be used smooth (not heaped), and mine (which I presume to be relatively normal) has 22 ml. That's more than a “dessertspoon”, obviously. But how much more? That depends on the shape of the spoon and how high you can heap. Multiply that uncertainty by the uncertain size of a cup, and you can have between 10 ml and 22 ml of ground coffee in between 65 and 285 ml of liquid, a ratio of 10 to 1 in strength. That's ridiculous. About the best advice is “vary according to taste”. My own choice is one 22 ml German measuring spoon per 200 ml cup, or about 11% by volume.

Pints and quarts

Some recipes use terms like pints and quarts, units still official in the USA and in use in the UK. But how much are they? If you're cooking, it doesn't make any difference where you are: it's where the recipe comes from that counts. A US pint is 16 fluid ounces, or 473 ml. An “imperial” pint is 20 fluid ounces, or about 590 ml. By some error, the fluid ounce seems to be approximately the same in both countries. The issue is further confused by “conversion tables” which are more rules of thumb (“a pint is pretty much half a liter” or ”a pint is pretty much 0.6 litre”).

Note also that in Australia, where the pint is no longer an official unit of measure, the term is sometimes used for glasses of beer considerably smaller than the old Australian (Imperial) pint, even smaller than the US pint. If you're used to this measure, your guesswork could be significantly in error.

No matter what kind of pint you have, a quart is two of them, and a gallon is eight of them, always assuming you have the same kind of quart or gallon, of course.

Weights

The (obsolete) metric unit for weight is the Bary. It died out centuries ago; I've forgotten which unit replaced it (Newton? Pascal?) though if somebody reminds me, I'll update this page. In general, though, weights are not important for cooking: what you want is the mass, and that's measured in grams and kilograms. The UK and US measures are ounces (28.35 grams), abbreviated oz., and pounds (16 oz or 453.6 g), abbreviated lb. The old Malaysian measure (see above) was katis and tahils. A tahil is 1 1/3 ounces, or 37.8 g; a kati is 16 tahils (1 1/3 lb, 604.8 g). That's not really too bad. The problem arises when you don't have any means of measuring weight or mass. The Americans are particularly good at weighing things in terms of cups (see above). The problem there is that the relationship between weight and volume depends on the material. You might measure rice in cups; measuring potatoes that way is completely ridiculous. Even in the case of rice, I'm sure that the relationship between weight and volume depends on the kind of rice.

</rant>

What I do

In my recipes, I weigh solids and measure the volume of liquids. It would be possible to weigh both, but it's not necessary for liquids.

I use a lot of spices. Spices don't weigh very much, and even the most sensitive traditional cooking scales are far too inaccurate. Nowadays you can get relatively cheap scales on eBay. Here's what I have:

This shows a clove of garlic weighing 7.68 g; depending on the size of the clove, it can weigh between about 0.6 g and 12 g. That really makes a nonsense of recipes that say “1 clove of garlic”, especially since the average size of a clove is locally dependent.

This is the reason that I specify things in weights. Sometimes this looks overly pedantic, but the real point is that I'm just recording what I do, especially when I'm experimenting. If I don't know what I did last time, there's no way to improve on it the next time.

The medium onion

What do you do when you see a recipe asking for “3 medium onions”? Onions vary in weight more than garlic: they can weigh between about 20 g and 1 kg. What's the happy medium?

I don't know, and if I didn't have to read cookbooks so often, I wouldn't care. But here are some empirically derived weights for things I use, in some cases based on measurements, in others on guesswork. If you have any input, positive or negative, I'd like to hear it. Note the weights of spices: whole spices can't be heaped as much as powder, so a “tablespoon” of whole spices tends to be about 3 “teaspoons”, whereas for ground spices the factor is about 4 to 1; yet another reason not to use volumetric measures. Note also the big differences in weights for different spices.

In some cases, weighing doesn't make sense. A stick of cinnamon weighs between 1.5 g and 2.5 g; if you get a recipe asking for 2 g cinnamon, and your sticks weight 1.5 g, are you going to take one and a third? Probably not. In this case, where the sizes are pretty uniform and the exact quantity not very important, traditional measures are good enough.

Object	Average weight	“Teaspoon” weight	“Tablespoon” weight
Medium onion	100g
Garlic clove	6 g
Ginger, per centimetre	7 g
Cinnamon, stick	2 g
cashews, whole			15 g
almonds, whole			15 g
Coriander seed		2.5g	8.5g
Pepper, whole		6g	25g
Cumminseed, whole		5g	20g
Turmeric powder		6g	24g
Fennel seeds		3g	9g