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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:

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

    A kati is a unit of weight that is obsolete even in Malaysia; it was 1⅓ lbs. “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 well-known law that addresses 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 measuring jug illegal?


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

Cups

Many recipes specify volumes in “cups”. That's a very bad idea: The definitions of a “cup” differ by a factor of almost two to one, depending on the country. Without knowing where your recipe has come from, you can't guess which one they meant. Also, “cups” as a cooking measurement are in general significantly larger than real cups. I've established that a cup can have at least one of the following volumes:

So the biggest real cup that I know is 200 ml, and most cooking “cups” range between 235 and 285 ml. If you use a real cup as a measure, you'll almost certainly measure too little.

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. My argument here is, of course, that it's never appropriate to use “cups” as a volumetric measure.

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:


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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.

Since I wrote this text, a page on this topic has been added to Wikipedia. I disagree with some of the opinions stated there, in particular that the differences are small enough to be disregarded, and many of the claims are not substantiated, but it has helped me update this page.

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       New Zealand
Spoon       measured       (“metric”)       (“metric”)       UK       US
      Volume       standard       standard       standard       standard
Teaspoon, kitchen       2.5 - 4 ml       5 ml       5 ml       5 ml       4.93 ml
Teaspoon, serving       4.5 ml       5 ml       5 ml       5 ml       4.93 ml
Dessertspoon       10 ml
Tablespoon, serving       11 ml       20 ml       15 ml       15 ml       14.79 ml
Tablespoon, large kitchen       17 ml       20 ml       15 ml       15 ml       14.79 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. Due to some accident, the units in New Zealand, the UK and the US agree pretty closely with each other, but not with common utensils.

On 13 March 2011 I discovered another example: a garden fungicide came with a measuring spoon which was supposed to contain 3 g of the product. In fact, I measured it at 7.5 g. That's really puzzling.

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 following measure, should be 19.72 ml. In fact, they're almost exactly 30 ml:


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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 about 473 ml. An “imperial” pint is 20 fluid ounces, or about 568 ml. 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”).

Don't believe that the fluid ounces are the same, either: they're closer than other measures, but there are still three of them. According Wikipedia the a British fluid ounce is 28.4130625 millilitres, and a US fluid ounce is 29.5735295625 millilitres. But for food labelling purposes, U.S. regulation 21 CFR 101.9(b)(5)(viii) allegedly defines a fluid ounce as 30 millilitres. None of this addresses the fact that a litre is an obsolete unit, and that they should mean cubic centimetres (and specify the temperature at which the measurement is to be done).

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

Strictly speaking, weights aren't important cooking: what's important 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.

What I do

In my recipes, I weigh solids and either weigh or measure the volume of 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 and accurate low-range scales on eBay. And they can show just how ridiculous specifications like “a clove of garlic” can be.

Typical sizes and quantities

There used to be information on typical sizes and quantities here. It now has its own page.


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