In June 2015, I undertook an experiment to test how good the Coravin Wine System was for pouring wine through stoppers and then re-cellaring bottles for pouring more at a later time. Read the blog here.
My one-year study demonstrates that the device can be used to pour wine out of a bottle, under the protection of argon gas, with no ill-effects in the first month. After the first month, there is considerable oxygen ingress through the hole created by the Coravin Wine System needle, and that test wines reach critical oxygen levels within 6 months and exceed thresholds within one year.
After one year, the test wine under the natural cork stopper had excessive ethyl acetate (nail polish remover smell), a markedly deeper color compared to the control wine, and was completely depleted of free SO2; it was spoiled. There was leakage through the cork very early on in the study.
The test wine under the twin-disc stopper had suffered in quality; it displayed a deeper color and was almost completely depleted of free SO2.
The test wine under the microagglomerate stopper performed best although oxygen levels also reached critical thresholds by the end of one year but considerably less than other stopper types, by one to two orders of magnitude.
The test wine under the polymer stopper was removed from the study once the stopper was pierced with the Coravin Wine System as it leaked excessively; this stopper type is clearly stated as not supported by Coravin.
All stopper types in control bottles performed very well with very low TPO levels and normal SO2 losses recorded at the end of one year; the control wine under the polymer stopper had the lowest TPO.
When using the Coravin Wine System it is highly recommended to sanitize the needle with a 70% v/v ethanol solution to minimize the risk of wine spoilage by acetic acid bacterial infection.