Weighing technology in importing countries has
progressed from the random check weighing of a certain percentage of the bags to
the accurate computerized weighing of each complete parcel, increasingly by
using weighing silos.
The European Contract for Coffee (ECC) states that
the sellers shall refund any loss in weight in excess of 0.5% of the shipping
weight. Unless weighing at origin is extremely accurate some argue that this
implies 'delivered weights' irrespective of what the contract states because
many containers travel long distances to the coast from inland filling stations.
But the underlying reasoning is that coffee in bulk does not dry out to any
noticeable extent and so should not incur any noticeable loss in weight
either.
Experience suggests that 90% to 95% of bulk
containers discharge within the laid down weight tolerance of 0.5% and that any
loss exceeding 0.2% is likely to be due to incorrect filling. There is therefore
no particular reason for shippers to add a little extra weight to avoid weight
claims (as is sometimes done for bagged coffee). Note though that large
receivers seldom bother to claim for small weight differences, preferring to
simply strike a recurrent offender off their list of approved suppliers.
Some receivers use the weighing mechanism in the
container gantry crane to establish whether the gross weight of a container
appears to be within acceptable limits. Should an individual box present cause
for concern then it will be discharged and weighed under independent
supervision. This is not feasible in arrival ports but is possible by special
arrangement at inland container yards.
But, the container can only be discharged into the
electronic weighing system of the roasting plant or silo park operation. This
makes the term 'supervision' somewhat theoretical, since all that will be
produced is a computer print-out and verification of the container and seal
numbers. Of course the supervisor could certify that the weighing system had
been correctly and formally calibrated in accordance with the laws of the
country where it is situated. The operators of such weighing installations
should be able to produce a valid calibration certificate on demand.