It is no secret that we love screw caps here at Pacific Rim. Unfortunately, there are quite a few misconceptions about them, so want to set the record straight.
The first screw cap closures on wine bottles were applied in 1959 by a French company called “Le Bouchon Mecanique” (the mechanical cork), which is now Alcan Packaging. Le Bouchon Mécanique adapted a mid-19th century canning technology to wine bottles. Despite its early potential, it was not until the early-80s that screw caps saw their first mass application in Switzerland – you can leave it to the Swiss to adopt clean and proper technologies. Today, nearly all Swiss wines are capped. Australia started using screw caps in the early 1970s under the impulse of several Clare Valley producers to protect their Rieslings from cork taint (yes, it was especially for Rieslings, folks) in the early 2000s. Since then, a large amount of Australian producers have shifted to screw caps and most of New Zealand’s industry has switched as well. In the US, Plumpjack was the first to try screw caps in 1997 but truly Bonny Doon (and Pacific Rim as part of the Bonny Doon family at the time) was the first winery to fully transition to screw caps. In the mid -2000s many domestic wineries had started to switch to screw cap closures, some by launching new brands, others after extensive trials (thank you to Hogue Cellars for their technological leadership). Today, Pacific Rim is one of the few domestic wineries to be 100% screw cap and we believe strongly in the organoleptic qualities of this closure.
So why do we think that screw caps are the best? Well, over the years we have had several problems with natural corks: First and foremost, they can taint the wine with 2, 4, 6, TCA (about 10% of all wines under natural corks are affected one way or another). Sometimes the taint is favorable (think oak, spicy or chocolate tones) but sometimes it is awful (wet dog, wet cardboard or mold). Second, they can let too much oxygen into the bottle, which can lead to oxidation, especially as the cork gets older and dehydrated. While some wines benefit from slow oxygen ingress over time (heavy reds for example), most wines age better in an oxygen tight environment. Another problem with cork is the variability between them (it is a natural product after all) making defects random and unpredictable. Over the past decade, this issue has led to the development of agglomerate corks made out of grinded cork particles in an effort to minimize cork variability. While we agree that the idea of reducing variability is good, we still prefer screw caps for all of the other benefits they offer.
Screw cap closures do more than just eliminating the TCA issue and the variability of corks; screw caps have a long life. A basic screw cap lasts for 10 years according to screw cap manufacturers, but the oldest wine samples under screw caps are 30 year old and they are doing great. In contrast, synthetic corks are rated for 3 years and natural corks for 20 years but require special storage conditions. Also, wines under screw caps are easy to store while natural cork requires the cork to be wet. There is no need for this with a screw cap (one caveat is that damaging the cap will compromise the seal). Another important benefit from using screw caps is it decreases the use of sulfites. Since the seal is airtight, the wine requires fewer preservatives, i.e. sulfites (this is important for us because we like to bottle below 100ppm total SO2).
One question I often hear is “all that aluminum pollutes more than a natural product, doesn’t it?” That argument is seducing because when you look at an aluminum screw cap and a cork side by side, you are quickly drawn to the conclusion that cork is good for the environment, while the industrial looking aluminum screw cap is not. If you account for the waste generated by cork, the actual low recycling rate of corks and the fact that screw caps are potentially the most recyclable closure (aluminum is infinitely recyclable), one can make an articulated argument against natural cork – though it is always complicated with a cork fanatic group. To be honest, just as most corks end up in a landfill, most people do not recycle aluminum enough in this country – I truly hope this will change. All that said, worrying about closure recyclability is a bit puny when you understand that glass recycling is probably 100 times more important than closure recycling (only 40 percent of all glass is recycled in this country – shame on us). If you really care about the environment, use lightweight glass and use as much flint (clear) glass as it is the most recycled color.
Now a couple words about screw cap technology, because this is more important than what you might think. The bottle is very important and needs to be quite high tech (much more than cork) because the cap is formed on the neck of the bottle – We require screw cap compliant glass from North America (I love the folks touting natural cork to save the planet and then use cheap imported Chinese glass…). The liner choice is important as well (the little disc inside the cap) because it is the seal (the aluminum envelop is just there to hold the liner). You can use either a Saranex liner (expanded foam with an internal plastic layer) or a sarantin liner (plastic with an internal tin layer). We use the saranex. Many other liners that would help the winemaker dial in the rate of oxygen ingress over time are being tested. Finally the screw cap application equipment is vital. The caps come unformed (like a cup) and they are formed with blades running unto the neck of the bottle – adopting the shape of the screw of the bottle. So screw caps are a bit more complicated than natural corks and much less forgiving of a bad glass bottle, a poor choice of liner or flimsy equipment.
Before screw caps we spent our life smelling cork, worrying about closure failure, sending 4 samples of everything – in case a bottle was “corked.” Sometimes it felt that choosing the right cork was the most important choice at the winery after choosing the right grapes. Now we can worry about more important things like the vineyard and the winemaking. We can forget about closures because we know every bottle will come to your table as our team intended – now that might be the best reason of all to use screw caps.