Bottling, particularly of off-dry wines, requires a considerable amount of attention to detail. Beware of:

• Oxygen uptake: Wine transfer, filler tank, bottle filling, bottle headspace
• Microbial contamination: Sterile conditions, filter wine, clean bottles & corks
• Other forms of contamination:: Bottle dirt, cork dust, bottling machinery grease

Some of the checks that need to be carried out include:

• Scrupulous hygiene in the bottling room
• Cleanliness of bottles
• Absence of leaks in the line to avoid loss of wine and oxidation
• Effectiveness of final filtration
• Correct fill height in the bottles (see trading standards regulations)
• Cork sterility
• Lack of damage to the corks or cork dust
• The capsules are applied neatly
• Labels are straight and well-positioned on the bottle

Larger operations will sometimes bottle wine hot (50ºC) or heat the bottles after filling to eliminate risks of microbial contamination.

A post-bottling analysis with stability tests is highly recommended.