The following question has been received: "A jar of jam is marked "454g E". What does the E indicate? When I query this no-one at the stores concerned has a clue.
Joe M"

We believe that the "e" indicates that the weight given is an approximation. In other words, a jar of jam marked "454g e" can be 451g or 457g.

The use of this symbol rather undercuts the much hyped-up usefulness of smaller metric units. It would seem to us that, if it is not possible to fill a jar to the precision of one gram, then the use of grams is inappropriate.

The "e" mark relates to what is commonly referred to as the average system of quantity control. The system was introduced in 1979 and the current UK legislation is the Weights and Measures (Packaged Goods)Regulations 1986.

CRITERIA FOR USE OF "E" MARK
Packages marked with the "e" are required to satisfy three rules which are:
1) the average quantity of a batch must be not less than the nominal quantity
2) not more than 2.5% of packages may contain a quantity which is below the nominal quantity by an amount which exceeds 1x"TNE" (see below).
3) no package may contain a quantity which is below the nominal quantity by an amount which exceeds 2xTNE.

(The TNE is a variable value which relates to the nominal quantity. For example, for packages from 50-100g/ml it is 4.5g or ml and for packages between 200-300g/ml it is 4.5%. The TNE falls to 1% for packages over 15,000g/ml. Other values apply to other package sizes).

There is no system of authorisation for the "e" mark - anyone can use it, so long as they carry out checks and keep records to comply with the above Regulations. Packers are subject to reference testing by trading standards departments.

Packages marked with the "e" may be freely traded within the EEA without being subjected to further metrological checks outside the country of packing or first import into the EU.

So, now we know.