The objective is to reject any bottles presenting any aesthetic defects, or defects that might weaken the bottle's structure, resulting in breakage if it suffers an impact, thereby causing a physical hazard for the consumer.
Quality control of the bottles can reveal various types of defects, in particular, air bubbles inclusion, chips, creases and scratches.
Origin:
Air bubbles can form during the glass-blowing process.
Origin:
Several rows in close proximity as a result of rubbing while the glass was still hot.
Origin:
Glass is chipped as a result of an impact.
Origin:
Accidental presence of a foreign body within the hot glass during moulding.
Bottle quality monitoring includes observation, which can be performed by the operators/inspectors. The inspection should ideally take into account the condition of the plastic bottle covers used for transportation. If these are torn, it is possible that bottles are broken inside the pallet.
Defects in covers can also create condensation inside the bottles as well as dust or insect accumulation. Once the overall condition of the pallet has been checked, a sample of several bottles at different levels should be taken to ensure that the bottles are compliant.
It is then necessary to check that there are no abnormal odours, and that the type bottle chosen corresponds precisely to the neck diameter and that there are no visual defects. The latter can influence how tightly the cork fits. If the inside of the neck is curved in any way, this will increase the compression of the cork at certain points and can affect the seal.
This situation was observed at Chateau Latour in 2008.
However, to achieve high quality, a visual inspection of each bottle by the human eye or by a machine is essential because certain defects may not be detected by statistical sampling.