Standing strong against metrification

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Although the rest of the world has gone metric, metrification in the US isn't really taking off. Perhaps it's due to the valiant efforts of the Americans for Customary Weight & Measure.

Obviously, changing to a new system of measurement is disruptive, but arguments about how "customary units" are more natural seem sort of weird:

Metrication results in huge numbers on food packaging (185g, 375g, 425g, 440g, etc). This vast increase in the size of numbers occurs because metric units are much smaller than customary units; 28 grams to one ounce, over 450 grams to one pound, 568 millilitres to one pint, and so forth.

This is sort of true for grams and ml which really are quite a bit smaller than ounces/fluid ounces, but even there most of the problem is that we have pre-existing packaging which comes in odd sizes when measured in metric. That's not surprising, since the packaging was designed to be an even multiple of customary units. It's straightforward to redesign things to be even multiples of metric units. For instance, .5 liters isn't any more unwieldy than 16 oz/one pint/one pound. So, this is basically a transition problem.

Metric units are derived from the geometry of the earth and have no frame of reference relating to foods, packaged or otherwise. This means that the number of grams or millilitres needed to represent a product is necessarily arbitrary, unlike traditional units that revolve around quantities typically dealt with.

This is just silly. There's nothing particularly natural about, say, inches and feet, and of course some English units are famously inconveniently structured (Fahrenheit degrees is the classic example here). Moreover, in cases where you need to use smaller units than the natural unit, metric is obviously better.

Metric fails to produce consistent or easily understood sizing scales. Unlike the 16oz pound that is geared to multiples of two, the kilogram cannot comfortably accommodate successive halving. Thus, while some metric packaging builds up as 100g, 200g, 400g, etc, this will not integrate with one kilogram meaning that other packaging progresses as 125g, 250g, 500g, etc. Other packaging uses 75g, 150g, 300g, etc while others still use 110g, 220g, 330g, 440g, etc. A large variety of packaged foods has no identifiable sizing scale at all, for example, tomato ketchup and brown sauce.

It's hard to see how the situation is any better here with customary than metric, especially in cases like ketchup and brown sauce where--as they point out--there's no natural scale anyway.

As I noted previously, most of these issues are about transitioning Metric units seem unnatural because we in the US aren't used to them and a lot of the things we encounter on a daily basis are scaled to be even-sized in customary units. If we lived in a country that had transitioned to metric, those units would feel just as natural. To give you just on example, I think about my weight and the weight of objects I encounter on a daily basis in pounds and ounces, but when I was in science lab I had no trouble thinking in grams and kilograms. Now, maybe the transition costs are too high, but it's not because customary units are more natural.

All that said, the two major advantages of metric are:

  1. The relationship between various units (grams and cubic centimeters, for instance).
  2. Decimalization.

The first property is built into metric, but isn't that useful in most non-scientific contexts. The second property is fairly easily adopted even if your base units aren't metric: for instance, in machining contexts it's common to work in thousandths of an inch and you'll often hear telco types talk about "kilofeet". Unfortunately, there are far too many cases where you need to intermix units that have no natural relationship between them.

6 Comments

Being from a metric country...

It's just nuts to talk about how metric units don't combine naturally, especially in the kitchen. And although things come in lots of sizes, eventually it tends to settle down to standard sizes for particular products (flour in kg, milk and cream in multiples of 300ml for small sizes), and you just get used to that.

Also, all the countries that have gone metric have standard metric teaspoons and tablespoons for cooking, which help quite a bit (usually 5ml and 25ml, although Australia for some reason uses a 30ml tablespoon... maybe because it's closer to a fluid ounce).

I think it's a failure of imagination, and is actually hurting the US a lot. But then, that's the nature of many of the US's problems.

That's weird. US teaspoons are 5mL, and tablespoons are 15mL. (You always see this in childrens' medicines, which are liquid and typically list their dose per 5mL. Though some concentrated infants' medicines do it on smaller amounts, like 0.625mL = 1/8 tsp.

The decimal scaling of metric units is convenient for calculation but not so handy for "meatspace" use. Simple "fold-and-cut" methods allow people to accurately divide or compose materials in binary and duodecimal fractions. I regard the fact that foods in metric countries are almost invariably supplied in binary fractions of kilograms or liters (half-kilo of bread, quarter-kilo of cheese, 3/8 liter of wine) as proof that binary scaling suits human beings better than decimal.

(I admit there are food-package counter-examples, especially in the candy-bar display. But most fit the special cases of (a) single-serving portions, where suppliers tweak quantity while trying to maintain a price, or (b) luxury goods, where suppliers wish to discourage price comparisons (that is, price-per-objective-quantity comparisons).)

I read a bit of the article residing behind the first link you posted, and frankly their argument doesn't have a foot to stand on.

Not an anti-metric argument per se (because there are none), but to me a big obstacle to kitchen adoption in the US seems to be that when the metric system is used, quantities of dry ingredients are specified by weight, rather than by volume. Most US households do not have kitchen scales (thank you, war on drugs! :^)), so this represents an actual incremental cost.

I don't have a scale myself. However, it's pretty easy to go from weight to volume using something like this:
http://www.sign-lang.uni-hamburg.de/hlex/konzepte/L5/L501.htm
Also, there's no reason why you couldn't just keep on using volumes in your ingredient listings.

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