Coravin Screw Cap: a second three-month trial
Coravin was originally designed to be a wine preservation system for bottles sealed with a cork. It works by inserting a fine needle through the cork into the bottle. Inert argon gas flows in through the needle, raising pressure enough to force wine up the same needle into your glass. Coravin claims that you can extract a glass of wine from a treasured bottle, which can be returned for further cellaring without deterioration and with continued bottle development. I have several bottles under trial and have no cause to doubt their claims.The Coravin Screw Cap seems likely to extend the life of wine, certainly for several weeks, if stored horizontally in the fridge, making it a viable option for serving wine by the glass in a restaurant situation.
A little over six months ago, Coravin released a Screw Cap adapter that they claim will allow bottles sealed with a screwcap to be preserved for three months after wine had been removed and replaced with argon gas. They now produce a Screw Cap with a silicon seal that replaces the regular screwcap and allows the needle to be inserted into the bottle.
I extracted around 150ml of wine using the Coravin Screw Cap and set the bottle aside with an unopened bottle of the same wine as a control. When I opened and tasted both bottles three months later the wine under Coravin Screw Cap showed obvious deterioration.
I contacted Coravin and eventually received a courteous reply from Coravin inventor, Greg Lambrecht. We discussed various reasons why the Screw Cap appeared to have failed. Eventually, I agreed to conduct a more extensive trial for a period of six weeks and three months with wines under Coravin Screw Cap stored vertically, horizontally, in a temperature-controlled environment of 14°C and in a non-temperature-controlled environment (my office, with a 7°C swing in temperature over three months). Each bottle under Coravin Screw Cap would be accompanied by two control bottles in case there was variation in the control sample. I chose Astrolabe 2013 Sauvignon Blanc.
When the time was up Cameron Douglas MS set up a blind tasting with the wines on trial, which were also photographed. The wine stored vertically at ambient temperatures under Coravin Screw Cap (the most affected sample) has been used to illustrate this post.
The samples stored vertically at ambient temperatures (pictured) had deteriorated the most in both the six-week and three-month trials. They had lost their fruit and were clearly suffering from oxidation. Storage temperature didn’t make a great deal of difference but did slightly favour the wine stored under temperature-controlled conditions.
There is no doubt that the Coravin Screw Cap greatly extends the life of the wine in an opened bottle. We didn’t bother putting it to the test, but it is fair to say that if we had removed 150ml of wine and simply resealed the screwcap it would be undrinkable in a fairly short space of time, even if stored at 14oC.
The Coravin Screw Cap seems likely to extend the life of wine, certainly for several weeks, if stored horizontally in the fridge, making it a viable option for serving wine by the glass in a restaurant situation. I don’t recommend relying on the Coravin Screw Cap for a period of three months, particularly if several glasses are extracted over that time and the wine in the bottle is a “mature” sauvignon blanc.