Fill by count or by weight

Why it is filled by weight

Counting is slow and error-prone at any volume, so a line weighs a target mass and relies on a consistent unit weight. That works exactly as well as the unit weight is consistent.

And capsule weight varies

Fill density, moisture content and shell weight all move, and a batch of capsules filled slightly heavier means fewer capsules for the same weight. The label still promises the count.

So the control is a measured unit weight per batch

Weigh a sample of the actual batch, derive the target fill weight from it, and check counts by hand at intervals. That is the ordinary practice and it is what makes a count on a label defensible.

Which is also the iron calculation input

The package iron total is the per-unit elemental iron times the count. If the real count drifts above the labeled one, the package total drifts with it, so the two controls are the same control.

Overfilling is the safer direction, within reason

A bottle short of its labeled count is a straightforward problem. Centering the process slightly above the count is normal, and it has to be accounted for in the iron arithmetic rather than ignored.

Record it against the batch

Unit weight, target fill weight, sampled counts and the date. 21 CFR part 111 expects in-process controls and records for packaging and labeling operations, and this is one of them.

And size the bottle to the count

A 60-count in a bottle meant for 120 rattles, chips and needs more filler. With 157 containers from 75 to 950 mL on this shelf, matching the bottle to the count is achievable rather than aspirational.

The label makes a promise about a number

Everything else in this property is about protecting the contents. This is the one control that protects a specific claim printed on the bottle, and a short count is the complaint a customer can verify themselves.

References