Cork vs Screw Cap – The debate goes on
Posted by Colleen | Wine News | Posted on February 6th, 2012
For those of you who are familiar with our wines, you will notice that some of them are finished with a cork closure and some are finished with a screw cap, or “Stelvin” closure.
The second most commonly asked question (behind “how do you pronounce the name of the winery?”) is why the difference in closures? To be honest, I wasn’t 100% sure as to why we made the switch a few years back, so I went where I always go when I have winemaking or other science-y questions that need answering: our production lab. This is where I can usually find our winemaking braintrust (this time of year, anyway…Harvest is another story) and have all of my winemaking questions answered.
Our production team made the decision to move some of our wines to the Stelvin (or screw-cap) closure as a measure to improve quality. Simple enough, but how does it do that, I wanted to know. With a screw cap, a consistently small level of oxygen can enter the bottle. This is opposed to cork, which allows not only inconsistent levels of oxygen to enter over time, but also greater amounts. The reason some of our wines remain in cork closure is that these are the wines that have additional longevity in your cellar, given their tannin components.
Tannins, obviously a key component in all wines, vary in level by varietal and winemaking technique. Without getting into the minutia of winemaking, wines that have good tannin will maintain their quality over a long period of time, as the tannins provide structure to the wine, among other things. The “bigger” reds, like Merlot and Cabernet Sauvignon, for instance, are described as such because they have more tannin, and thus cork lends itself to the natural aging process, allowing those tannins to open up in the bottle. Obviously, there are other components that will lend themselves to the ageing life of a wine, but in general, white wines (think Sauvignon Blanc) traditionally have less tannins and therefore aren’t considered to be wines that age like a Cabernet would.
For example, our Pinot Noir is a more fruit-driven, less tannin-driven varietal than our Merlot, and because the tannins are not as predominant as they are in the Merlot, the screw cap preserves the quality and taste of the finished wine better. Our winemaking team determined as much through extensive laboratory and production trials before making the switch from cork to screw cap. Truly, the decision was made based on which closure would display and preserve the varietal characteristics better. It probably sounds like a marketing and PR statement, but I have it on good authority that is the case. I may or may not have sneaked into the lab to partake in a trial of more fruit-driven varietals (Chardonnay and Pinot Noir) from vintage 2004 and 2005 with some bottlings of the vintages in screw cap and some in cork. Screw cap won for these varietals, btw.
In the end, it’s all about the contents of the bottle, as opposed to the method by which the bottle is sealed, I suppose, but it’s nice to know there was a method to their “madness.”