For a very long time, cork was the preferred method to seal a bottle of wine. There has been much debate over the past few years as to what the best method is for sealing off a bottle, cork, plastic cork or screw caps.
Current estimates predict that roughly 6 percent of all wine bottled with a traditional cork will fall victim to TCA (2,4,6-Trichloroanisole), a bacteria that thrives in cork. Some of you might have even had a spoilt bottle of wine and not really noticed it. Even a very small amount of TCA in a bottle of wine can ruin it. Most become aware of TCA in quantities as small as 5 parts per trillion. When TCA is present in quantities high enough to be evident to a person, it comes across as 'musty' aromas and flavors. TCA in wine is not toxic, but the taste and aromas can be quite unsettling. https://www.batten-machinery.com/product/imm-screw-barrel/ Another issue that seems to have people leaning away from traditional cork is the fact that cork can dry out and allow air to oxidize a bottle of wine. This can happen if a bottle is not stored correctly. Storing a bottle of wine on its side helps a cork remain moist and a moist cork expands better to seal the inside of the bottle. A dry cork shrinks allowing air to enter spoiling the wine.
Plastic corks have been created to help combat the problems being seen with real cork. Plastic does eliminate the problem of TCA, but plastic corks can have leaky seals which cause oxidation. Personally I have never had a problem with a leaky plastic cork, but it does happen. Another problem with plastic is that they can be very difficult to remove from a bottle compared to cork. Though this is not as detrimental as having a bottle of wine ruined with TCA, it can be very frustrating if you were looking forward to a lovely glass of Chardonnay and the plastic cork wont budge.
In an almost last ditch attempt at preventing wine from spoiling, some wine makers have resorted to screw caps for their bottles of wine. Not nearly as romantic as the popping sound a corked bottle makes, screw caps nonetheless are very effective in preventing wine from spoiling. Most Australian wines are no longer made with cork and have opted for this screw cap method because its better at maintaining the taste of wine in the way the wine maker intended.
Screw cap bottles of wine are becoming more and more popular, and yes, while they are not as aesthetically pleasing and continue to hold the connotation of a cheap bottle of wine, a greater number of higher quality wines are opting for the screw cap to prevent spoilage. So the next time you are served a bottle of wine with a screw cap, think twice before brushing it off as a cheap wine.