Imperial habits die hard

The attention of Metric Views has been drawn to a question appearing in the ‘Problems solved’ section of the November edition of Which? magazine. It relates to washing powder weights and volumes.

A reader in Plymouth, Devon, posed the following question:

“Why are washing powder measurements in millilitres?

I bought a 650g pack of Tesco Non-Bio Powder laundry detergent. When I looked at the packaging to see how much to use, I saw that the dosage amounts are in millilitres, a measure of liquid, not grams for solid weight. How do I work out how much to use?”

Had this question been directed to Metric Views, we might have responded that the same metric measures of volume are used for solids, liquids and gases. Simple and logical. One reason why metric measures are now almost universal.

If asked to give examples, we might have pointed out that, for example, cubic metres are used for ready-mix concrete, for the sizes of rubbish skips, and for metered water and gas supplies; that litres are used for garden peat, soft drinks and the capacity of suitcases, and that millilitres are used for liquid medicines, cosmetic creams and, yes, washing powder.

The reply from Sara Ingrams, Which? laundry expert, was as follows:

“According to the EU Detergent Regulations, washing powders must have the dosage printed on the packaging in either millilitres or grams. It is easy to understand why laundry liquids and gels’ dosages are given mL, but it is less obvious for powder. These used to be given in mL, but most brands now also print a conversion in grams on the boxes. Tesco told us it expresses the dosage in mL because people use a scoop (with the volume in mL) to measure the powder for the wash, as the pack instructions advise. It added that it is working with its supplier to add conversion details to packs.”

We at Metric Views use a scoop to measure out wash powder, and would not dream of using the kitchen scales. What about our readers?

We are reminded of a comment that appeared in a motoring magazine some years ago. A reader complained that the manual for his new car gave the capacity of the boot in litres which he found strange as he did not intend to fill it with water or any other liquid!

Imperial habits, however illogical, do indeed die hard.

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9 Responses to Imperial habits die hard

  1. Ezra Steinberg says:

    At least you guys over in Britain can use metric. I just read in The Guardian that Alton Brown, host of the cooking show "Good Eats", was not allowed to use metric on his show by the Food Network:

    So sad. 🙁

    But now he is going online with is show, so he can use metric to his heart's content. Hurrah!

  2. Martin Vlietstra says:

    The [British] Guild of Food Writers advocates using metric units in their recipes. They have a good page on the use of metric units for cooks at

  3. Daniel Jackson says:

    In this situation, I don't see it so much as an imperial habit refusing to die out, but how to practically measure washing powder. Which is easier, scoop the amount of powder needed or pull out a balance and measure the precise mass? Using a balance is more technically correct but is it worth the effort to use a balance?

    The compromise in this situation would be for the makers of the powder to either include a cheap measuring scoop calibrated to an exact number of grams equal to one dosage or to sell as an option a calibrated cup with markings indicating the amount in grams based on the powder's density to the marked line. Of course this cup would only work with that particular brand of powder.

    Indicating on the box a relationship between grams and millilitres based on the powder density would be the best compromise.

    Expressing the space of a car boot in litres is the lazy way to do it. Advertisements should express all three of the linear dimensions because expressing volume only doesn't tell you how that volume is distributed.

  4. Mark Williams says:

    `Contents may settle in transit'. Measuring flakes of anything by volume is less accurate, but getting it slightly wrong with the laundry (they always recommend a considerable overdose, anyway) is preferable to contaminating the scales which you likely also use for food.

  5. Martin Vlietstra says:

    @Daniel Jackson

    It is highly impractical to use length, height and width for a boot, especially when you have an irregularly shaped boot. I am not sure how boot volumes are measured, but filling the boot with ping-pong balls and then counting the balls is a simple way to account for all the irregularities that one finds in a boot.

  6. BrianAC says:

    Asking Which? to explain metric is like asking the blind to lead the blind.
    Soap powder and similar have always been measured by volume, be it 'scoop' 'capfull', 'cupfull', 'handful', 'measure', etc.
    Come on now, really, anyone out there ever seen their mother or grandmother get the kitchen scales out to weigh 1/2 ounce of soap powder??
    Which? like the BBC should get a grip of reality. The answer given is just another anti-EU, anti-metric rant to make it all look difficult.
    The real answer should have been " .. because that is how it has always been done, it is just the units of measure that are different, ... ".
    Finally, after 40 or 50 years someone has woken up and found out their washing powder is in grams.

  7. jackthesmilingblack says:

    "Give him an inch and he'll take a mile."
    These common expressions are part of the culture.
    You can even, on occasion, hear an Atheist exclaim. "Oh, for Heaven's sake".

  8. Martin Vlietstra says:

    Sayings change with time. "Give him an inch and he will take a mile" was originally "Give him an inch and he will take an ell". The ell (45 inches) was the pre-1824 unit of measure of cloth. In reality it was a "double-ell" as the ell itself was the length of the forearm (22.5 inches), but over the years the word "double" was forgotten. The original saying was well rooted in the tailoring trade. Now people use the "mile" in the saying under the assumption that it was there since time immemorial.

  9. Mark Williams says:

    @Martin Vlietstra:

    Ah, the inverse Avagadro Project method for measuring capacity ;-)? I'd bet that instead they simply take the 3D CAD model (of the internal space) and press the `calculate volume' button. Much the same as with the area of towns and distance by roads. Typically, the base data will be in SI and so naturally will the answer be---for conversion to litres or imperial [square] miles, etc. NB: also works for things as yet unbuilt.


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