Why wine bottles leak and how to avoid it
It’s true that sometimes wine bottles can leak in transit, so we asked ourselves, “is the problem global wine transportation or is it something else”. Our study revealed that on the rare occasion a wine bottles did leak, it was due to the seal and closure failing. Leakage, can be caused by factors including improper cork selection. This can damage labels and cartons and add cost, whilst diminishing brand integrity.
What causes wine bottle seal failure?
Our research showed that the major sources of leakage caused by seal failure in bottled wine, are excessive pressure in the bottle and on the closure, and bottle faults. So, when filling and closing a bottle here’s what should be taken into consideration:
Filling the bottle
Wine should be bottled at (or near) ambient temperature not in cold conditions. Too chilly, the wine will expand as it becomes warmer creating pressure in the bottle. For inserted closures, the length of the closure effects the fill height. Allowing sufficient bottle headspace (the gap filled with gas between the wine and the closure) can counteract the issue.
Closing the bottle
Although pressure can cause leakage, corks and synthetic closures require a certain amount of pressure inside the bottle neck to maintain an effective seal. The bottle neck bore profile also impacts on the sealing of inserted closures. The seal of a screw cap on the other hand, relies on the integrity of the gasket in the top of the cap and a smooth bottle neck rim.
Price, material quality and product to be filled, also weigh heavily in the choice of closure.
Packing the bottle
It’s nearly impossible to tell if a cork has an internal floor which may cause it to fail. The quality of material and the upright position of the bottle for a time after filling (cork recovery) should create an effective seal. More obviously, physical damage from denting due to mishandling, greatly compromises seal integrity.