Why do wines have corks? And, are screw cap wines inferior to wines with corks? In today’s video Annabelle McVine discusses screw top wine and wine cork to answer this viewer question. The humble wine screw cap has been the cause of much debate over the years. And everyone loves a wine bottle with cork. But, are there any downsides to wine cork? And what are wine corks made of? WineScribble explores the wine cork tree.