1. A loose Needle could cause some leaking or dripping while pouring. Please ensure that the Needle is tightly attached to the Coravin unit. You can check this by turning the Needle grip counter-clockwise until there is no more give to the turn.
2. If you have previously accessed the bottle the most likely reason that a cork will leak is that you have used the Coravin System with a synthetic closure. Although this will not damage the Coravin Needle, and will still allow you to pour wine, the cork will not reseal, and oxidation will occur over time. If you have accessed a bottle with a synthetic closure, store it upright.
3. If you are accessing a bottle with a natural cork that is below room temperature or chilled, the cork will take a bit longer to reseal. This does not mean that oxygen is entering the bottle during the resealing process, the argon in the bottle is still protecting your wine.
4. It is possible that a small amount of residual wine in the Coravin Needle pooled in between the cork and the foil upon removal of the Coravin System from the bottle. This excess wine can sometimes leak from underneath the foil even though the cork has fully resealed.
5. If you access a bottle with a natural cork in poor condition, it is possible that it will not reseal fully and leak.