Wine cellar. A man checks samples in a vineyard wine cellar. Bottled wine stored in a consistently cool, dark cellar can improve in flavour over many years. Acids and alcohol in the wine react slowly together to form molecules called esters, which give the wine its distinctive smell, or bouquet. At the same time, the levels of tannin (the bitter principle from the grape skin in red wine) and acid fall, making the wine taste smoother and less tart. This wine cellar is part of a Californian vineyard where wine is mass-produced on an indus- trial scale using modern technology and mechanized techniques. The cellar contains over 200,000 samples. Photographed in California, USA.