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.