All screwed up? No, not really! In this Carneros Club shipment there is one wine of the three that has a screwcap on it (the 2024 Unoaked Chardonnay), and I often ponder the role of screwcaps. How are they good, how are they bad, and when are they appropriate?

The first time I remember screwcaps being used on wine was around the year 2000, maybe shortly after then, and they were a mystery to most winemakers at that time. There were cautions on how the wine needed to be made and also prepared for bottling, and also nobody knew how long a wine could be aged with such a closure! Before screwcaps the only other alternative was synthetic corks – pretty much a plastic type product – and I used them for many years without much satisfaction. I only used the brand that could be recycled, and also the wines did not seem to stay as fresh as I wanted them to. I used the corks on the fresh, fruit driven wines like Sauvignon Blanc and Rose trying to keep them fresh.

After I saw other wineries using screwcaps, and seeing how our bottler put a screwcap machine on their mobile trailer because of demand, I decided to give it a try. I still wanted to try the caps on the same types of wines as the goal all along was to preserve freshness and hopefully age well for a few years. I then tried the caps on the same wines, but mostly on the rose and Tamarix (slightly sweet rose), and I was satisfied.

So what is a screwcap made of? It is pretty simple, having a flexible aluminum shell that comes to the winery straight sided, and on the inside of the top is a disc that proved the seal. There are two types of discs, a tin one featuring a thin layer of tin placed over a softer backing, and the other is called Saranex. This liner is, surprise, made of thick layer of Saran Wrap! Both liners provide the seal but they are also what slows the flow of air into the wine, and they let through air at different rates. The tin liner seems to be for longer aging reds, but I have seen white wines with this liner. The Saranex is made for shorter aging wines that are meant to be consumed quickly, within a few years. Screwcaps are pretty simple in reality, but they do have ups and downs!

The upsides are many and that is why we are seeing so many on wines in the marketplace. The main upside is that the wines with the screwcaps are not going to be “corked” – when any mold in a natural cork reacts with Chlorine to produce a “wet rag, wet dog, wet cardboard” aroma or flavor that ruins the wine. The percent of all wines with natural corks that are “corked” is still around 2 to 3% so using screwcaps prevents this. The other upside is that screwcaps make the bottle of wine resealable easily as well as easy opening of the bottles. No corkscrew? No problem! Open in one second! The last upside is the cost savings to the winery – the cost of a screwcap is 25% of the cost of the total cost of a cork plus a capsule.

There are a few downsides to screwcaps though, and the biggest is the perception that the wine is of inferior quality. Cheap top = cheap product. Traditionalists still like cork for the ritual and it has been used for such a long time that we are used to them. I remember years ago when a Napa Valley winery was putting screwcaps on their $100 Cabernet Sauvignon bottles and that was a huge controversy. I don’t know of any high end producers putting them on now but I do know that some countries pride themselves on using screwcaps for most of their wines (Australia) and some really good wines have those caps! The other downside is that the caps must be put on correctly and the grooves put into the caps just perfectly, otherwise the bottles don’t seal or you can’t open them correctly. The bottling line machinery pushed down the cap for the seal and at the same time spins metal discs around the outside of the caps to make the grooves for the bottle threads and at the bottom section of the cap the machine tightens the cap under a lip in the glass, which prevents the cap from popping off. When bottling we check regularly to make sure the seal is good and that the caps unscrew easily. It’s not like a cork that you can see is in the bottle and has a good seal. You have to be sure otherwise it could be a lot of ruined wine!

I do think that screwcaps are good but I don’t have the confidence yet to put them on more wines than the ones I have put them on because of aging and acceptance. Maybe in the future I will expand to a chardonnay other than the Unoaked Chardonnay, but for now I’m still being traditional on most wines!