What about the packaging tare?

Direct measurement of the net weight is only possible with the destructive method. There, the packaging is opened and emptied.

If we have a closed package that we do not want to open, we calculate the net weight by subtracting the tare weight from the gross weight. Two methods are possible here:

Method 1

Before filling each package, measure its individual tare, then measure the filled package and subtract its individual tare.

This method is used in particular for glass packaging with large differences in weight.

Method 2

The average tare is determined from a sample of 10 packs. The weight of the filled packages is then measured and the average tare is subtracted.

This method can be used provided that the tare determination error does not exceed 1/4 of the value of the allowable error in determining the net mass (0.25*T1). It is necessary to take into account the error of determining the tare caused by the dispersion of tares of individual packages and the accuracy of the scale used.

In practice, this method can be used for plastic and paper packaging, which usually have small differences in weight.