Cork vs. Screwcap: Here Comes the Science

Cork vs. Screwcap: Here Comes the Science

There’s nothing quite like the sound of a cork popping out of that fresh bottle of wine, indicating it’s time at last to drink. The “click” of a screwcap seal being broken… well, it just doesn’t do the same thing for the senses.

If Hogue Cellars has its way, you’re soon going to be willing to put the corkscrews away for good. Hogue has long been a screwcap champion, to the point where it has spent tens of thousands of dollars bottling wines with a variety of closures just to see what really works best. It released a study in 2004 that backed screwcapped wines over cork-stoppered ones, and another, even bigger, study released this year, according to Hogue, seals the deal. In fact, it is now moving all of its wine production to screwcap closures permanently.

That may be a hard sell for some, so Hogue showed up in San Francisco recently to try to prove its case firsthand. But first, some science. It turns out not all artificial closures are created equal. The company evaluated seven different types of screwcaps and three artificial (plastic) cork-sized stoppers to figure out, well, that some are great and some are crap.

The details were long enough to fill a two-hour presentation, a 40-page PowerPoint, and an entire website about the issue, but it boils down to this:

  • In the long-term, screwcaps with plastic (aka Saranex) liners were best at maintaining a wine’s flavor (as judged both by expert tasters and SO2 measurements): Other screwcaps (including those with tin liners) let in too much oxygen.
  • Most synthetic stoppers are junk.
  • Natural cork isn’t bad — but it suffers from unreliability; bottles vary quite a bit from one to the next.

If only it were that easy: Even different Saranex screwcap manufacturers vary in quality. And then there’s the issue of headspace — the air trapped in the bottle after the cap is put on. In a corked wine, there’s very little air in there, but in a screwcapped wine, there’s quite a bit: There’s no cork filling up the space that is now empty and full of ambient air. You can fill this space with nitrogen or just let it breathe. (Hogue tested that too and now does that latter.)

The highlight of this event was Hogue putting its money where its mouth is: We tasted a vertical series of six Hogue Chardonnays ($11 bottles), all screwcapped, from vintages 2004 to 2009. Now I’ve had old, cheap, California Chardonnay before and it’s invariably been swill once I uncorked it. Hogue, however, proved this doesn’t have to be the case. Its 2004 was rich, buttery, and just about perfect — reminiscent of lightly aged Burgundy. I liked the ’05 to ’07 bottlings the least, but none of them were bad, proving pretty clearly that screwcaps can truly stand the test of time.

We then turned to reds: Five 2003 Genesis Merlots, all the same wine except for the stopper. Tasted blind, the crowd was asked to pick favorites. Most liked the A and B bottlings best, which were the screwcapped versions of the wine (one with nitrogen added and one without). But two of us (myself included) preferred D. It turned out to be, you guessed it, stoppered with natural cork.

Why did I like it? The A and B wines tasted too young, though a 2003 Merlot should be perfectly drinkable today, this was still tight and tannic, and tough to sip on… even after aerating for hours in the glass. The cork-stoppered wine, however, had a little age on it. Oxygen isn’t always a bad thing, and here it had done a little magic by giving the wine more austerity, more restraint, and better balance. I wasn’t surprised to hear that, but it was disheartening that half the group felt the wine was bad: The bottle their samples had been poured from was corked. Such is life in the world of natural cork, and it’s a sad fact that makes it clear why Hogue has gone the way it did.

So, is a screwcap better than cork? Not necessarily, but it’s certainly nothing to fear. A good cork will work just as well as a good screwcap (look for a white liner inside instead of a metal one) — and there are bad versions of both. How you figure out what you’re getting without opening the bottle, well, that’s a problem for another day.

Christopher Null is the founder and editor in chief of Drinkhacker. A veteran writer and journalist, he also operates Null Media, a bespoke content creation company.


  1. Jeff on July 17, 2011 at 1:16 pm

    There is something worth noting with the use of screw caps…it is highly probable that their benefits may be best expressed under certain conditions. Wines that are supposed to be consumed young or those varietals characterized by a light to medium body and are “fruity” tend to be those that I have noticed to really benefit from screw caps.

  2. Christopher Null on July 17, 2011 at 3:30 pm

    Jeff – that is likely a more eloquent way of expressing the way I felt about the effect of screwcaps on the aforementioned wines.

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